Comments by "SeanBZA" (@SeanBZA) on "Technology Connections"
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Numitron backing is grey because RCA used what they had in spades, the sheet steel with aluminium coat that was used to make anodes and internal structures for thermionic tubes, and this was proven to survive the glass sealing and gettering operations. Thus they used the standard tools they had in the tube plant, the flat anode sheet, slightly formed to be a stiff backing, and punched out the holes needed to hold the filaments. Then used the technology they had to make glass beads with wire in them, and sealed those into the holes, making the filament supports, and then simply used a flat section of that steel wire that was bent over to hold a length of thoriated filament wire, also a common item in the tube shop. Length and diameter calculated for the brightness needed at the applied voltage, and then simply placed in location, the ends folded over, then spot welded together to trap the tungsten wire under slight tension. Then at the rear spot welds to a lead frame attached to a standard off the shelf 9 pin glass base, and you have the complete unit. Glass top attached, and then evacuated with the standard roughing pump, and as a bonus because of the low voltage, and no need to maintain an ultra low vacuum, the roughing pump and the heat sealing of the tube is all that is needed to operate, no need for a getter to be installed, and no need to flash it, just a RF heating during sealing to get a high vacuum, then seal.
Incidentally there were small versions made, the same size as your common 7 segment LED displays, and they were very popular, as they ran off 5V, and interfaced with logic. They worked best using CD4049/50 CMOS level shifting buffers, as those would source or sink 50mA no problem. Using a buffer/inverter per lamp, and a BCD decoder or counter per digit allowed those displays to be bright, and as bonus you could also use the blanking input on the drivers to use PWM to dim them.
Project to replace those displays with LED ones worked, just that it really did not drop display current use, it was still 5A of current at 5V, though it was good in that at least you had a display that now was available, using a tiny HP 7 segment red display. Do one conversion and you had 16 numitron displays to use to fix others, so we only converted 3 boards to the LED version. Biggest problem was the resistor value selected was too low, so the LED displays were running way too bright, so had to be dimmed. Rather than destroying the cordwood board made to fit them, I simply used 2 6A silicon diodes in the common line, to drop the voltage seen by the LED displays down from 5V to 3V8, which made them dim to exactly match the old displays. Those 2 diodes were hard to fit in the limited space left on the display board. Users liked the new crisp displays, the bright version got complaints that it was so bright it was unreadable at night with dark adapted sight, and it lit up the entire cockpit. Display dimming had to match the other display, and that board used unijunction transistors, and had a disconcerting habit of the power transistor unsoldering itself from the wire leads, it ran so hot. Base lead unsolders itself, transistor is still conducting, runs hotter and lamp blows. Select spare lamp and it also blows, unless enough time for transistor to cool below 200C junction temperature. Would have been nice to have had some of the more modern mosfets that can handle 50A, but not at the age of that design.
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@alexanderkupke920 Jet A1 is kerosene that has been dewaxed, removing all the longer chain molecules, so that it will not turn to slush at -40C in the aircraft fuel tanks. The wax that is removed is further classified by melting point, so you get soft waxes that melt around 40C or lower, often sold as Vaseline or petroleum jelly, and harder waxes that melt around 70C, which are used to make candles, and as a base for many cosmetics and shoe polish. Higher melting point waxes are also used in industrial applications for various things.
Diesel oil is very close to paraffin or kerosene, just has a somewhat less and slightly different range of melting and boiling points and density. To further confuse things you also have Rocket kerosene, which is a very highly refined Jet A1, that is designed not to freeze till around -100C, and which also has even less wax in it.
In general you can run the diesel vehicle on kerosene, but it will run poorly, as diesel has additives in it to lubricate the fuel system, which is needed, plus the wax will tend to clog fuel lines and injectors as it flows through and undergoes local cooling. Same for a jet engine, which will run on diesel, though it will smoke heavily, as the fuel is not being fully burnt before it leaves the combustion chamber.
Run a modern GDI engine on kerosene and it will very quickly fail, but older mechanical injection engines do not care, and will run on diesel, kerosene, Jet A1 or even vegetable oil, provided you can get it liquid enough to flow through the pump.
Lamp oil can be also a blend, with it consisting of a mix of kerosene, diesel and even lighter oils and benzene to make it light easier, and also can have aromatic oils added to it to have an odour other than the distinct one.
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Duracell also made blister packs of cells with the tester in, as discussed. The resistive element is actually screen printed conductive ink, which is based on silver powder, in a carrier based on printing ink, screen printed onto the plastic sheet, and then this thin sheet was dried, and the back had the thermochromic ink screen printed onto it, followed by the top layer being thermally bonded, to make a 2 layer sheet with the tester in it. Then the paper insulator was applied, pre punched out for the gap where the thermal heater needed insulation, and the one hole for the switch, the cutting die finishing separating the paper from it's supply roll. This was then punched out, and applied to the large sheet of battery label on the adhesive side, so you had a large self adhesive label, that had a release side applied, and this again got partly cut out, to leave the battery sleeve on the backing layer, excess being weeded off automatically. Then slit into working rolls, and applied on the line.
Very complex, and needing lots of precision sharp cutting dies, so no wonder they decided the much higher cost and complexity per cell was not worth it. Thus the shift instead to use almost the same test unit, just with 2 strips of adhesive on the top, to the blisters, saving a lot of money, as you only had one per 4,6,8 or 10 cells. Then cost was cut again, and with all the assorted contract manufacturers not wanting to pay the cost, they went back to just labeling generic cells off a random production line, as Duracell is now nothing but a brand name applied to whatever generic cell was the cheapest quote to make a few hundred million cells, no quality required as they are running off name recognition. After all, no longer will they replace or repair equipment damaged by leaking batteries, they will only pay you a voucher for the cost of a new set, if you pay to ship the leaking batteries to them, at your own cost.
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One reason they have not replaced them with LED is that they are old controllers, and thus also have old conflict monitors, which are there to monitor all the lights, so that no fault can cause the light to show go on cross directions at all, any fault that might do that will cause the conflict monitor to disconnect the controller and go to a flashing red all round as a safe indication of it being a 4 way stop. Old controllers are there till they run out of spare parts or the pile of others removed from service, and will only be replaced with new controllers when the old ones are out of stock completely.
Newer controllers can have LED drive as standard, but are difficult to retrofit to the old controller, as they probably are from the 1980's, where the controller also had current sensing that allowed remote monitoring of lamp failure, allowing non reported lamp failures to be repaired without having to have a monthly check on all lamps by a crew, and also this showed the relays were working correctly, giving a backup for the conflict monitor.
Had this happen here, where the last 2 Automotor mechanical controllers were replaced eventually with Siemens controllers, hope the old controllers were kept for the transport museum though. On some of the controllers they had to add "cheater" lamps in the controller case to provide enough load to make the controller and conflict monitor happy with LED loads, but as almost all the controllers also had lamp soft start built in the lamp life of 8k hours was more like 20k hours as they were either kept slightly powered by a low current or had soft start resistors to keep inrush current low.
If the municipality wanted to save money they could also just get by replacing the red and green lights with LED, leaving the orange as incandescent, as the 5 second on time per cycle is really low power overall, but red and green are the major power draw. Plus the burst of heat in amber helps to keep the snow off, though here, where the last time snow fell was millions of years ago, extra heat is not exactly needed. Have seen LED clusters showing 2 colours on the same pole, then a 30 second flash as conflict tripped and made it all flash red, before cycling back again to normal for the rest of the timing cycle, and then rinse and repeat.
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Major driver was cost of licence. Sony had a per machine royalty, while JVC was a lot less worried, with both much lower costs and a lot less actual chasing up, so that manufacturers would look up the cost of making a machine design, and choose the cheaper option and make VHS. As well the actual mechanics were easier to make, quite a few clone manufacturers could do the entire machine easily enough, but only found the head drum assembly too difficult, so resorted to buying them as spare parts for larger brands. Did drive Matsushita crazy for a while IIRC, with the number of head drums they were selling to the repair market, till they finally found out why, and probably started offering them as a ready to use part instead, getting in an extra profit for essentially already paid for production capacity. Then the cloners got to the point they could actually make the whole machine in house.
Sony however wanted tight control, which both costs money, and also stifles innovation and changes to the mechanism, while VHS found a solution to big drums in the VHS-C with the smaller drum, faster rotation and extra heads with switching, but which left a standard azimuth track on the tape, which also was used in a few full size smaller units as well. Assorted mechanism types were to get it either smaller, lighter, cheaper, or more compact for some application. Last VHS decks I saw consumer side were essentially one single plastic injection mould of all the parts, integrated with a single sheet metal stamping, to make the deck, complete with all of the tape mounts and eject mechanisms.
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@AaronSmart.online Ceiling fans are a definite must in the tropics and sub tropics ( so most of the EU, aside from those places around the Med, are out), and all of them I have met start off as high, medium and low. mostly because they tend to have bearing issues with time, and the bearings ( or bushings, depending on how old the fan is and who made it) will tend to become sticky with time, but so long as the fan is able to start turning they will run. Thus you start on high, to get the best chance of the bearing getting it's hydrodynamic film built up and thus reducing wear, as a slow moving bearing or bushing is going to have very high loss,, simply because of metal on metal contact.
In general the fans only start to give issues when older, and often I cure it with a new capacitor, as most ceiling fans I meet are not shaded pole types, but split phase. Bearings getting stiff it is possible to lubricate them, but often the housings are pressed together, making it hard to get to them for a good repair, and the modern trend is to use that horrid CCA wire as well.
The ones on my ceilings are around 20 years old, and still work well. The smaller fans almost all are split capacitor, though the old GE fan is rather odd, in that it achieved phase rotation by having variable reluctance in the pole pieces, using thinner sections of the poles to provide a saturating magnetic field. As the field saturates it appears to shift, allowing the fan to start as the field is moving, and not just varying with time, just like the shaded pole does, but without the need for the copper shorting coils to bring about the field saturation in the motor. higher starting torque simply because there is no circulating current in the pole pieces, so more energy available to induce a rotor current, plus the rotor is skewed, so there is a bias as to start direction built in.
Yes 230VAC country, currently ( amazingly) 233.2 VAC , though it can go up to 247VAC at times, but after they replaced the 90 year old transformer across the park (it started leaking from the base valve, so went for repair instead of just a new valve) the newer one ( still around 30 years old, they are refurbished because of the cost of new ones) is set more closely to 230VAC instead of the old one being 240VAC. I lived in a place with the original 130 year old 250VAC supplies, and there cooking was great, but appliance and lamp life was not, though your lamps were extra bright. That will never change, as they would have to replace over 50 transformers at once, so keep the taps on the low side instead to meet spec for high voltage.
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Monochrome CRT you can get to 20k lines with ease, just requires a very small beam diameter inside the CRT, this determines the spot size on the CRT, and you can make a very small spot if you are prepared to have a low brightness. Colour CRT you could get 2k screens, but they were both insanely expensive and a bear to align, and would have colour fringing if you moved them at all, and also would have fringing with any ferrous metal moving nearby them. The most common use for high resolution CRT's was film digitising, using the CRT as a line source and then slowly scanning the film past the line, with a photomultiplier tube getting the video signal off the transmitted light. The resolution possible on the best was better than most film stock. Colour was done using a colour filter wheel or dichroic mirrors to separate the colours and handle them separately, the CRT providing the white light source to drive them. Simpler ones were used regularly to transfer film to video for TV transmission, using a variety of methods to get the video signal off the film at TV scan rates with the film running at 24FPS.
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Well, the 3 colour tube projection TV sets have a non shadowmask display, though the front screen is lenticular to provide a brighter image in the forward view by concentrating the light in that direction in rear projection sets, the ceiling mount ones use just a diffused screen ( or one with a reflective layer to provide optical image brightness gain to the centre for the same reason, higher perceived brightness for the same CRT brightness) to scatter the image in the room. Line resolution in a mono CRT and rear projection 3 CRT set is more to do with bandwidth of the video circuit, or how fast it can go from one predetermined brightness to another predetermined brightness ( typically 80% to 20%) and then how many of these cycles it can do in a single horizontal line before the difference between the 2 levels is no longer displayed. Thus you get the 500 odd pixel display resolution, which basically translates to the roughly 7MHz bandwidth the TV channel has allocated to it, the set cannot display more lines than that without exceeding this bandwidth, and this is the big reason for the resolution. Vertical it is fixed by the number of lines in the interlace, with the 2 half frames each drawing an image with half the lines, then the other half of the frame filling in the image in the blank space between the lines drawn on the other half of the frame. Overall it looks like a single image, but it is 2 with a line offset between them, the eye integrates the 2 half frames into a single one.
With monitors that are not TV sets you can get higher bandwidth, up to 70MHz or more for the last of the CRT monitor displays, which meant you could get much higher resolution, allowing you to use a much finer pitch shadowmask in the CRT to get a sharper image, though the trade off is both more complex alignment in production, more complex drive circuits to get the beam to stay aligned perfectly in all the positions it scanned on the display, along with the smaller phosphor dots meaning you had to drive them with higher power to get a bright image, thus the big risk of image burn on these CRT units. CRT displays also used an aluminium sputtered backing on the phosphor layer to reflect light back to the front instead of losing it in the inside of the CRT, which did not affect the electron beam, but which doubled the brightness, though the thick dark glass reduced this again to give increased contrast ratio on the image..
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@willford7717 To be fair to company coffee, it does taste crap even when fresh, simply because I will bet you nobody has ever stripped the machine and cleaned the basket, or even the carafe, let alone run descaler through the water circuit.
I do go to a place where they have the automatic machine, and the first thing I do there before pressing is run the cleaning cycle, which puts out a lot of nasty gunk every time. Then select espresso, and then cappuccino, and pour the first into the second. Only ever tried the stuff they call tea once, it tasted terrible, sort of vaguely tea like smell, but it was definitely not a good tea at all.
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How about coffee bags, which is ground coffee in a tea bag, which you brew in a tea pot, exactly the same as tea, or in the actual cup itself, like a tea bag, removing when at the desired strength, and enjoying the brew as you like.
Me, I drink instant coffee, and yes there are some brands that are better used as brown colour for dirt, but there are a lot of instant coffee blends on the market. Filter yes if I am out, but for what you get at the price, it is not always worth it. I go past the overpriced green logo coffee place to the shop behind them, which serves to my taste a better brew, and at the same time I can indulge in my fast food meal, a chicken salad with hot sauce, and peri peri chicken livers. Place the order and 2 cups, first for while I wait, and second for the walk home.
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In floor ones also come with a cam and spring, because they are almost always dual action, able to open either way. Made so you do not need a left and right one for double doors, only a single box buried in the floor, and the closer screwed to it. They do have speed adjustment for each side separately, so you can adjust them to be one direction only by screwing the other side valve all the way in, so it will not allow flow. they are also able to handle much heavier doors as well, and last for decades. Most common make by me is dormer, known to last a half century in use. They can also be rebuilt as well, as dormer does have kits of spare parts for them as well. you do need however to demount the door to do so, which means you need to pick up a very heavy door off the lower pivot after you unscrew the lever that retracts the top pivot. Or in the case of the one side, cut through the pivot on top first, as the adjuster had rusted solid in the 50 years of being there, so I got the 2 new complete units, and the one door was a breeze, just needed Rockset 5 minute cement to fit the new box in the old one, but the other one needed 2 days of work to get the door hardware off, and the new hardware on. Lots of 5 minute epoxy and wood to fill holes from old screws, and then grind the new socket to fit the pin, and same for in the frame.
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@danl6634 I installed an inrush limiter on a 7.5kW motor, because the original installer connected the DOL starter incorrectly, and it was starting in delta, then switching to star. Then dropped a phase in the one contactor due to arcing or dust. I replaced the lot, plus put it all, along with the 7.5kW soft start unit, into a dust proof cabinet, and set run up time to 30 seconds. Solved the issue of the unit tearing itself out of the floor bolts. Of course the biggest issue was to remove that 130kg cast steel frame motor from the gearbox, where the shaft was kind of not willing to separate, even hanging the entire motor mass off it. Had to use a BFH and crowbars, and the trolley I had under it suffered badly. New one was light, only 78kg, so easy to lift up with the chain block, and that shaft was well greased.
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@TechnologyConnections The way those work is to use either the condensing coil fan to sling the water over the condenser coil, or to use a condenser coil below the evaporator coil, so it drips down via gravity and then is channelled over the condenser fins. This then allows the evaporating water to provide extra cooling for the coil, improving efficiency. The big drawback of this is the uncoated coils corrode really fast, and in general only last 3-4 years before they are only a mass of corrosion products on the inside, blocking the air flow, and bare piping that is running hotter than safe ( higher pressure, greater erosion inside the microgrooved pipes, oil breaking down from the high temperature into acid and carbon) and ultimately failing. Outside they look fine, but are totally blocked once you get to the fan chamber.
Window wall units do the same, unless you remove the rubber bung and install the optional drain line, though most of the new ones do not come with a drain, and expect you to replace the entire unit after 4 years, from the case and coils being rotted through. Note the warranty is only 3 years on the compressor only, the rest of the unit is only statutory warranty ( often a year) and in general you find they never get a warranty claim, as if the compressor fails within 25000 hours ( they rarely do, even though they are cost cut way down, but that is another story) that is a rare failure. Coils however are often badly rotted after only a single season if you live near the sea, like I do.
Split units have to have the 2 drains, though often the outdoor unit drain is rarely installed, as in heat pump mode the outside air will be very low humidity anyway in winter. They do build up amazing amounts of sludge and bacteria though unless regularly serviced and cleaned. The inside plastic parts are black, so the sludge mat does not show visibly, even if the rest of the unit is light coloured plastic.
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Not as critical, as the interference pattern causes a large variation in return light, but any pit approaching the required depth causes some interference, and the return light is less. The receiver in the player is not too concerned about the actual variation, just that, relative to the transmitted light returned from the smooth surface, there is some loss, and that this is enough for the player to discern the pits from the lands. There is a variable gain stage that compensates for the variation in return before the data slicer in the laser electronics turns this very analogue voltage into a digital signal for further processing. This analogue voltage is also filtered and forms part of the focus, as it tracks the average distance between the laser focus lens and the actual data layer on the disk, and the lens is kept a constant distance despite the actual disk having variability of up to 2mm per rotation in use.
Then there is the fact the receiver is actually 4 separate photodiodes in a quadrant, so the signal is the sum of all of them, but the difference between opposite pairs of the diodes is used as info for the focus system and the 2 linear tracking servo loops that keep the laser beam following the single long spiral track faithfully, despite it not always being concentric in the disk itself.
Incidentally almost all the laser modules were developed by Sony, and you find a whole range of KSSxxx laser modules used in CD and DVD players, all operating on pretty much the same principles, but with various layouts and mounting methods used in them for various players. Now almost an industry standard module, often no longer made by Sony, but still with the KSS part number.
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Same for washing machines, I live in a soft water area, so use a quarter of the "manufacturer recommended" dose, and it works well, with no residue, and no floating growth in the machine either. Also not connected to hot water, and the generic Unilever store brand detergent as well, because, shockingly, the biggest difference between brands is the scent package, and the amount of brighteners added, along with possibly a slightly different amount of borax as filler.
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Not mandatory here in South Africa, but many of the new units come with this by default, as the units are imported and thus they comply with the big US market safety and ancillary wise. Older units do not have anything other than chimes, and some that are from the 19th century are still in use, just having to have safety upgrades ( door glass with safety glass instead of window glass, inner doors instead of the lattice steel, an emergency light and bell in the car) to comply. The new ones are almost always, in a retrofit or as a lower cost add on to existing structure, a motor room less one, and the hydraulic powered elevator is almost unheard of here aside from in some very old, no longer approved for passenger travel, goods hoists that have no in car controls or lighting. Even a goods hoist new has to comply with passenger car regulations.
When you upgrade an older unit ( controller and car interior upgrade, replacing only the inner skin, the floor and the lighting, plus the call panel and trailing cables, along with a new controller driving the existing motor and gearbox, sheave and cabling and shaftwork) you typically get the audible signals and direction signs as part of the package, though they might not be installed in some buildings due to lack of space and no wall boxes.
Your building I would speak to the elevator service company, and they can plug the modules back in to the controller, and simply unscrew each panel and use the volume control built in there to drop the volume down to quiet. Suggest to the building owner that the penalties for non compliance with the ADA are pretty high, and deliberate non compliance can result in multiple lawsuits against them in person.
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There is no audio in that application, just video, and often just mono video as well, as this needed less memory. Most switchers used a 2k RAM chip and a video flash ADC to sample the video, using 4 sample and holds to drive the ADC, and using the sync signal to determine where in the RAM to do the write. Output was a simple scan of the entire RAM to a DAC to generate video. The one I have somewhere used a Z80 and a 6116 SRAM for memory, with the control program being in a 2716 EPROM, plus the flash converter and a quad SH chip, along with some simple sync detection. Unused inputs would be set to a blank screen, and it could either do 2 or 4 on a single output, or switch in sequence, genlocking the output so the TV would not twitch during the switching.
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The fob on car works well for metros, who use a particular chain in the area, and thus all the vehicles can simply come in, and fill fuel. At the same time the CCTV also captures both the vehicle details, driver details, and the link also does double duty, with it also transferring info about mileage driven as well, so this all is automatic. The vehicles that either fill up too much, or who do not match the description on file, are all flagged automatically.
I had the same, a tag that worked at the local garage, simple to go there, tap and fill up, no other things, as each driver had the tag linked to them, not the vehicle, but the recon at the end of month would have all data available, so looking up this was easy, just email a query, and it came back a day later complete with images and full data from the pumps themselves.
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Common in smaller units, it is around a third of the price cheaper, though I change them to double pole ones when replacing them, even though I live in a country with 230VAC mains, as the double pole unit as a spare part means you only need to keep one to cover both use cases, and then a second 3 phase unit for bigger units that run on 3 phase, where you have a 4 pole unit typically, with 1 pole also used to power the single phase cooling fan separately. Double pole means less issues with tripping when the wiring outside gets wet, as you typically will have the unit hard wired, and thus simply turning it off will allow you to fault find and isolate the unit. Plus compressors often fail as a short to ground, with split phase the unit might keep on running at part power, till the motor itself burns out the wiring.
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Still have a pack or three of Phillips 22W tornado CFL lamps, which do actually last around 8 years in use, on all night. bought them around 2000, a whole case, and they will probably last me a long time still, as they are the last lamps they used good capacitors in, and also used full size TO220 transistors in on the board, so do not cook themselves to death like the new ones. Still have black PCB material at EOL, but at least the transistors do not run that hot that they unsolder themselves, like the modern ones do.
The main capacitor also sits in the socket, so runs cooler, though of course it still get well toasted. Pretty much every one goes EOL with the filaments wearing out, not from electronics failing. Which seems to be the main issue with LED, in that you either have the driver die, or the dies themselves get the black spot of death on them. Ah well, if I run out of tornados I still have a number of magnetic ballast conversion units, which plug into a standard B22 socket, and take a PL lamp in the top, those pretty much will run till the plastic falls apart. PL7, PL9, PL10, PL11 and PL13 all work there, the magic of constant current, and glow starter construction in the lamp.
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Those horrorlytics in there do dry out with age, as they are often cheap no name brand units of questionable quality. However film capacitors of the same capacitance and similar voltage rating can often be put in the same place with no issue. Cables are just snake oil, at under 10m I just use regular 1.5mm mains cable, and you cannot tell the difference between that and the $5k cables ( I got some, after the test I recycled them into test leads, because they have PTFE sleeving so are somewhat smoke proof) in most cases. With the sound source being a PC audio chain, and the speakers and amp being low cost used, they are absolutely not needed.
Did have a house where the expensive cables were used, till they vanished into the floor, and were cut in the hidden side and joined with wire nuts to 2.5mm house wire to the other end. Twisted to get them to lay together, then joined back to the other end the same way under the floor. HIFI " Guru" could not tell the difference between them.
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@renakunisaki I did do that, buying 25W golf ball lamps by the gross, and needing to replace them at least once a month as they burnt out. However the downlighters used good lamps, and as they were always slightly underrun the life was good. When the shop had the ceiling ripped out I found a few of the original stock Osram lamps in there, still working perfectly, though the reflector of them had basically become transparent, and quite a few had simply flaked completely off. 105 downlights, swapped out after a month from 50W to 20W, because the difference in energy use was considerable, and also you needed half the amount of AC unit to keep it cool. Even so there was a second AC unit installed, as the main one could not keep up with trying to cool the whole area.
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You are wrong with the internal pressure switch in the condenser, it is normally run on the low pressure side, and is set to provide protection in the case of low refrigerant, switching off the compressor when the suction side pressure drops too low, from a loss of refrigerant. Then you do have a thermal cutout inside the compressor, that does break the full current, though better units also include an external overtemperature switch, turning off the compressor when it exceeds 120C case temperature, with the internal one operating around 140C. Better ones also include another switch in the high pressure side, turning off the compressor, typically with a non resettable trip, when pressure is too high, normally caused by the fan not running to move air over the fins, or the fins are clogged solid, and the high pressure side rises up in pressure to a very high pressure from the hot gas being in there.
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@sprockkets Only ever had one unit that actually came with a heater for the compressor, and that was because it was run really hard, with inlet suction at 0C, for a split AC. It killed compressors, and eventually just charged it to around 5C at suction, and it ran a lot better. After all discharge temperature was around 70C on the high side, dropping to 40C when the hot liquid left it, so it was definitely running flat out. Put a large liquid line drier on it to give more liquid volume and a little more restriction as well, fixed cap tubes and not wanting to do the manufacturers designing for them. Left the heater off then, it was a lot happier, just pulling a nice puddle of water from the air instead of the ice block.
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Your split using has multiple capillary tubes feeding the indoor unit coil, with a directional valve to provide a restriction in the flow depending on direction, so that you get better efficiency in the different cycles. There is another restriction in the outdoor unit, so the line leading in is a cool liquid at low pressure, instead of a warm liquid at high pressure, reducing the volume of refrigerant needed. This restrictor is also varied according to flow, acting as the expansion device in heat mode, and pressure reduction in cooling mode.
The coil outside is a lot larger in area, so the unit is optimised for cooling the indoors, but in heat mode the larger coil allows longer run time before defrost, though the heating capacity is lower than cooling, but as you typically are not removing latent heat of condensation it all evens out, the airflow is too fast to allow much to condense. Typically the units meant for heat pump operation and the regular non heat units use the same control boards, and simply have a few bits set in the microcontroller to tell operation mode, though often the board is the same, just with a different terminal block, or non used terminals. Outdoor unit is simpler, only with a single control line to turn fan and compressor on together, and with no sensor wires to give outdoor coil temperature.
Heat pumps you will have with the inverter a control board, first thing to fail, and you will find it is NOT covered with the typical 5/10 year warranty, on the compressor alone, on inverter units. The non inverter heat pumps are almost as efficient, and with a control board that is inside the indoor unit, and only a relay outside to control the compressor, with the fan speeds controlled by 2 or 3 wires, and then a control for the reversing valve (power the valve to make the unit heat, default to cool otherwise), and then only a inlet air temperature sensor and perhaps a coil temperature sensor half way along the coil, where the refrigerant is changing phase from liquid to gas. Indoor unit has the same sensors, inlet air temperature, and coil temperature.
These determine operating mode, the indoor ones in cooling will stop the unit cooling down when the coil starts to freeze up, from either too low airflow or too humid, and the outside ones will dial back the cooling if the refrigerant is getting too hot. In heat mode the same, though the freeze sensing is more important.
In the climate I live in heat pumps, though pretty much the standard, almost never get used to heat, so the valves often will seize up in place, and then the units will have strange faults, as the tiny volume of refrigerant in the non used valve heats up and moves the spool in it slightly, causing the compressor to leak refrigerant from outlet to inlet. Inverter units tend to be damaged from power surges, and the outdoor unit circuit boards are also prone to failing, as they are exposed to the hostile environment, and run either cooked or frozen. Not covered apart from the regular unit warranty, and you almost never will change a compressor under warranty, as the manufacturers will either insist on the board changed with the compressor, or will scrap the unit, as the outdoor unit coils will likely be almost totally destroyed before that 5/10 year period is up. Inverter board failure will probably burn out the compressor on one coil as it fails, and you will have a fight for the warranty.
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100A service is a massive power capability, here by me the standard is 60A, and generally the only time you are going to trip it is if you have 8 individual AC units running flat out in summer, which is not that common in a residential setting. Business, running out of a converted house, will get there, but the easy solution is to go first to 80A service (just a change of breaker and meter, as the wiring is rated for 100A anyway, set by the supplier regulations and the supply side fuse), till you have to install the new cable and go for a 3 phase 60A supply, which will run a small industrial unit perfectly fine.
Very rare not to be able to get 3 phase power, you really have to be rural, and far out, as the standard is a 3 wire 11kV or higher distribution cable, as the losses are lower, though many farms went with a single phase, as they have to buy the cable, so plenty went for the cheap option of 11kV SWER supply, as you only need a single cable, and a giant buried ground mat at the transformer, saving a lot on the cable cost. Does mean you also get single phase AC motors up to 22kW, biggest you can run off a 60A supply, as power source for pumps in rural areas, and a lot of farms have a good deal of 11kV wiring, contactors and transformers, owned by the farm, or leased from the electric authority, with a single meter at the connection point to measure power.
But in cities, or close to them, standard is 3 phase power, and houses are fed from a single phase, which is plenty enough for 95% of all houses, unless you have the multi million dollar houses, where you need a 3 phase supply, because your electric bill is sitting north of $20k per month.
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@surelyijest Thing is efficiency is hard to measure, you need precise calibrated equipment, which is expensive, while life measurement simply needs a 24 hour timer, set to give 4 15 minute shut offs a day, and a simple visual count of the number of lit lamps. Does take longer, but also is a lot more accurate, as you do not have to calibrate to get the relationship, which is not linear. The 5H45m on and 15 min off emulates a daily cycle, allowing the bulb to cool down so it has start cycles on it added in, as otherwise an always on lamp does last well over 1000 hours in use, as the only stress is slow filament evaporation.
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I live where a heat pump is almost useless, in that there are only 3 or 4 days a year where it would actually be useful to have, though the AC is useful most of the year round. however adding in the reversing valves and the extra wire is almost zero cost to the manufacturers, though for cold climes I would say better to optimise the unit for heating rather than cooling, which the most common ones do not do, so the cooling takes slightly less power than heating.
Best thing though for any heat pump is correct installation, not right against a wall, free space around it, and more than the minimum the manufacturer says. Seen way too many stuck right up next to a wall, with no clearance other than the feet, so the coils barely flow any air at all, and plenty stuck right on the ground, with plants growing all around them. No air flow, no heat pumping either way, and lots of money being wasted in power, plus poor performance.
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@Stego27 Yes, though most commercial ones will have power factor correction, so the initial current will be a large single cycle pulse to charge all the PFC capacitors, then the lights will turn on in under a half second. Incandescent lights have a much worse surge, I built a soft starter for a light box, that used 40 40W golf ball lamps, because the switch on surge was large enough to trip the breaker it was on. Soft starter made the surge low enough that it would not trip, and they came to full brightness over 2 seconds. easy to compensate with exposure time anyway, as you had a latitude of 5 seconds for the photographic plate exposure, and more variability due to temperature. Original artwork was done with Letraset and large format photo negatives, and then later on a Apple Mac and a Imagewriter dot matrix printer onto transparency, followed by a Laserwriter when they came out, doing laser tranparencies.
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Nissan electronic module has a small RC oscillator in the chip, and a driver that divides it down from a higher frequency, so the resistor and capacitor values can be reasonable close tolerance parts, then use the shunt resistor (the loop of wire on the board near the relay contact) to detect lamp current when on, and if it is below a threshold it will switch to a higher flash rate to indicate a blown bulb. Current typically is set so the trip point is 2 21W lamps triggers it, but if you have the 2 21W lamps plus the 5w lamp it is high enough that it will not run at fast rate.
Some also have an added threshold, so if you have 4 21W lamps ( hazard operation) on there it will flash at a lower rate, with a much reduced duty cycle, so that a vehicle on the side of the road will have the hazard lights run for a much longer time before the battery is flat. Generally with this you also need to install a trailer relay unit if you want to tow with the vehicle, which removes the trailer lamp load off the circuit, and thus the trailer unit also often will include, if it is the OEM version, another lamp fail circuit that will tell you if trailer lamps are faulty as well.
Modern vehicles have body control modules at the rear, where they drive each individual lamp separately, and also monitor them all the time to check they are not faulty. Thus the indicator and brake lights will also fail safe, in that if a brake light fails, the indicator will come on at constant brightness on the side that has failed, in concert with the other side, though generally almost all vehicles that have body modules for the rear lighting use LED lighting for all lights, except the reverse light, which is still an incandescent lamp, as it will almost never fail, other than from accident damage. Still have lamp failure detection in them for the LED units, though that often requires using a dealer diagnostic tool to get the information, as that only sets a failure indication when all LED units in the signal fail.
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Finish also runs very regular bulk specials on the packs, and as well the pack size is variable, so that you can get a pack with 21, 30, 36, 48 all on the same shelf, all of them almost identical in size, but with only the one pack size discounted, so you often pick up the bigger, more expensive per unit, accidentally.
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@smashed_penguin Only because you paid for the cells that Duracell actually does QC on, the consumer line is identical (down to the tooling marks on the actual cells in most cases, and the lot numbers hidden under the label) to the no name cells you buy all over, just look for ones with the same expiry date, and you find out they came from the same machine line.
The one I want to find is the OEM who did the cells for Proctor and Gamble, as used in Airoma machines, a plain white sleeve cell, but I never had one ever leak, even though I used to buy the intro packs, as they gave 2 refills, and the dispenser, for the same price as a single refill. I had lots of those 2 cell packs around, that were really high capacity, low internal resistance, and which lasted at least 10 years in use, not even leaking when empty. Not even an expiry date, just a lot number on the cell itself under the sleeve.
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The fancy kettle also uses the exact same element as the cheap one, just they use a nice blob of cast aluminium alloy to bond it to the stainless steel plate, and then also put a ring of blue LED's right next to this 150C block of aluminium, to light up the water, so you know it is on. Bets are will the LED dies fail, or the element, but they never last beyond 2 years anyway, with moderate use of once a day for a half kettle of water. Same as the cheap one, made in the same factory, with the same electrical parts.
Of course, if you want a no wait solution you can go buy a Zip Hydroboil (does need 230VAC to run it, and you have to have it plumbed in with both water supply and a steam vent pipe, along with the power connection rated for 15A draw) and have up to 19l of boiling hot water right there when you need it, and never fill it up again. Uses a 2.2kW heater element to boil the water, and keeps it just at a slight boil, in an insulated copper tank, and then has a small auxillary tank that has the float and fill valve, that keeps the level in the big tank constant, but also does not fill it fast as used, so it will not ever be below 95C. Thermostat uses the steam, venting into the small tank, to trip off power when the small tank lid hits 60C, so the main tank is always just short of boiling.
A few sizes depending on use, from an office with 4 people, to a hotel that does morning coffee and tea to 200 people that all want boiling water over that hour of breakfast. All the parts that fail, tap, element, float, valve, safety switch and thermostat, are spare parts, and easy to change out as well. Just the price is a little more than the $15 kettle at Wallyworld (expensive, the cheap ones here are $10, with a 1 year guarantee, and actually do often outlive it), so be prepared to shell out $847 for the most common 10l model.
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Data in the VBI was generally a SMPTE timecode for the source video, used to display a time counter and frame number for the use of the editor. The other info was close captions, and then you could also have alternate data streams that contained things like title . This came from the original video tape, either Umatic, Betacam or Betacam SP, and was simply transferred to the video stream either by the TV stations or by the duplicator. TV stations would often strip out the SMPTE codes to instead add station control codes, transmit flags ( is this for certain areas only on a national broadcast, or to add local adverts during breaks) and the local transmitter text data, but line 21 would generally be left alone.
The Macrovision blocks were generally not going to interfere with the timecode, but the only thing was that the video clamping would be confused by the ramp and would thus result in the decoder not getting a good signal out. Professional VCR units had the ability to turn the video AGC on and off so that you could then record the Macrovision info onto a tape without interference, and also turning it off on playback meant your video was not going to suffer from data corruption during the edit stages as well, though you only put the macrovision on at final dub stage, so that it would have less effect, as it still did cause degradation of the video by not giving as good a vertical lock.
Professional VCR units would record macrovision effortlessly, and Panasonic made a lot of semi professional ( Prosumer) VCR units with this available, mostly used for home video editing where you also had generation loss and not having multiple AGC actions lessened the video degradation somewhat. You would have only the camera AGC enabled to handle the initial shooting light variations, then use the edit deck to do your effects, cuts and non linear editing ( you needed an edit deck, and also at least 2 VCR units slaved to it to do the non linear editing before HDD recorders and digital video) and record to the master tape. The edit deck could also do the audio dubbing in linear stereo in a second pass, though HiFi stereo required you to have the audio dub already set up to record.
You could get really good results out of that, as good as the best professional edits, as good as VHS could deliver both video and audio wise. just needed a good source video.
As to the Teletext and such, pretty much European TV sets, or at least anything that used the Phillips chipset for TV jungle processing had text built in for either free ( for the later chipsets where everything was in one chip and a front microcontroller with an I2C bus connecting them) or with only a small second text processor and a few control bit changes. Siemens also had a set of chips that did this as well, so any of the European TV manufacturers ( Grundig, Phillips, B&O, Normende) and almost all of the old satellite TV decoders as well did both close captioning and text even on the basic sets. The USA had their own chipsets, and most of the European chipsets did out of the box PAL,NTSC in assorted flavours, and SECAM with either no added changes or with only minor changes, but the US ones only did NTSC.
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The popular Kerosene stove used here, almost the most popular cooking method, as it works when the electricity does not, and gas has a high initial cost for use, does not need a starter fuel to use, just pump it up and get it high enough in pressure to spray a fine mist, then light, and it will stabilise down to an even heat in seconds.
Same for the lamps, though there have been a few models recalled because they had soft solder on the "brass" parts, which melted in use, and you had the whole unit pop apart and spray hot boiling kerosene, here paraffin, all over, with a nice ignition source for the hot gas as well right next to it. Saw racks of them that had been seized by the regulatory body, ready after the case to be taken and crushed, then sold for scrap metal.
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Brake lights, the thing so often not functional on many vehicles, where you might only have the centre high brake light working, more because it has 5 3W filament lamps in it, that are not run as hot as the others. The LED versions also fail, or the brake switch had broken and stuck on long before, burning all the lamps, incandescent and otherwise, out from overheating. I see on average around 1 in 10 vehicles with one or more lights not working, and this includes both brand new, as in still with paper plates, all the way to vehicles that are mostly describable as rust and body filler moving in close formation.
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The tubes shrinking from T12 to T8, and then to T5, was a result of increasing phosphor efficiency. The T12 phosphor was essentially the same phosphor since they were initially developed in the 1920's, and was very limited in operating temperature and allowed light emission. Thus you needed a certain area of phosphor to get a defined light output.
Later improved phosphors allowed both higher light output, and higher operation temperature, and also the smaller diameter tubes allowed a reduction of volume of gas fill, and also a drop in the amount of mercury in them, so the mercury went from almost 100mg for a T12 lamp, to 5mg for T8, and down to under 2mg for a T5 tube. CFL units are at around 0.2mg of mercury per lamp typically, ironically making recovery of the mercury near impossible, as it is so little. The biggest killer of them in enclosed and any fixture is that most of the power dissipation is in the filament ends, where you have to heat up the emitter material, so generating all the heat right by the electronics, and also in a nice insulating plastic enclosure. green PCB at manufacture ends up at EOL as being charred black, along with pretty much the entire inside of the lamp.
Drawback of LED units is that they are also full of large amounts of toxic metals, Gallium, not so bad but still a heavy metal, and Arsenic, part and parcel of the Gallium Arsenide used to make the light emitting diode chips used in there, plus of course the phosphors are pretty much the same ones used in the flourescent lamps, and those are also a witches brew of heavy metal oxides, enclosing the GaAs chip.
Flourescent linear lamps are easy to recycle, mostly glass, a bit of nickel wire, some strontium and tungsten, and a little fill of aluminium and copper from the ends, plus the water soluble phosphor inside, because it is deposited using a water based slurry. Crush up the tubes and wash them, and the wash water has almost all the phosphor and mercury, because it tends to bind with the phosphor (which is why you see so many T5 lamps that are pink, because the tiny amount of mercury in them has been adsorbed onto the phosphor coat strongly), and then you simply use eddy current sorting to pull the metal parts out, and melt them down again, and the glass goes into a furnace to make new ones. CFL units harder to recycle, you have to separate the electronics and the tube, and then mostly just recover the copper and dump the rest, and the same for LED lamps, if recycled only the copper is stripped, all the rest is just more waste to be dumped or buried somewhere.
There was a brief period where CFL units had replaceable glass, as the idea was to reuse the electronic unit ballast and have a simple east to replace light emitter, but the integrated CFL quickly killed that as they were cheaper to make. Still have a few of those units around, and they will outlast the LED units very likely, as I also have a good supply of the PL flourescent lamps they use.
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Yes, I have installed a few of them, because it was easier to do so, but yes I prefer the LED lamp. However the LED drop in flourescent tube retrofit is a great item, well worth it to get. Incidentally I also have some very early implementations of the CFFL lamp, a base you put in, that then takes a PL lamp in the top, so you can replace the lamp when it fails. They were perfect in 24/7/365 application for over a decade, only needing new lamps every 5 years or so, mostly because they also were good quality EU made lamps, and also because they were run base down, so there was no real heat into the magnetic ballast.
At the other extreme I also have a number of lamps that date from that Phoebus cartel, NOS, with the same spindly single wire filament, both in carbon filament, and tungsten or tantalum filament. Clear and frosted ones, in general dating from before 1939. They are really nice as mood lighting, though with power ratings in candlepower, 16 and 32, or 40 and 60W rough equivalent, they are not exactly stellar in light output, but definitely give that incandescent colour.
Did try running a few on higher voltage, they work up to 340VAC, when brought up slowly over a few seconds, which is something no CFL or LED will do, they all will pretty much blow up at around 270VAC input, either with a bang, or just a small pop. At 340VAC they are insanely bright though, likely with a lifetime measurable in minutes, like your regular photoflood lamps had.
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Freezer on the bottom you have a smaller freezer compartment, as it has lost volume to the space for the compressor. As well the insulation there is thinner, to minimise the lost volume, plus it has a lot of hot piping running through thin sections of the insulated wall near the inside, along with 200W of heat from the compressor itself when running.
Chest freezers have the luxury of having thicker walls, so there is more insulation, while a fridge freezer upright combination has thinner insulation, and the door also has to have a heater in the inner wall, so that the seal does not freeze onto the case. Larger length of seal area, thus more heat input to keep it not frozen. Seals also lose heat to convection, long vertical strips of airflow allowing heat inside the box, while the chest freezer has almost no convection along the seal in most cases.
As well the limiting factor in modern fridge freezer lifetime is not the compressor, those will easily, even for the cheapest ones you find in modern fridges, with cost cutting applied everywhere in manufacture, last 10 years running all the time, provided there are no leaks in the gas system. Sadly that is the killer, the foamed in insulation is done with isocyanate 2 part foam, and as a side effect of the cure they do release acid slightly. This will eventually cause the evaporator pipes, and the condenser pipes, to corrode through from the outside.
Most pronounced at the regions of the piping where they are cold enough to condense water from the air in the evaporator, thus at the cold side where the pipe enters, and for the condenser at the hot side, right by the door, where the hot gas is used to keep the seal from freezing in place, and which cools down from heat transfer to the inner side fast when the compressor stops. This then corrodes the steel pipe, used instead of more durable copper, as it is a lot cheaper, and when a small pinhole eventually does corrode through the pipes you are unable to repair it, as the pipes are all buried in the foam, and removal is going to require destruction of either the inner plastic moulding, or the exterior steel skin to expose them, and then you cannot replace the foam easily after replacing the pipes. Look at your modern fridge with a thermal camera and you see where the pipes run, and how haphazardly they are installed before the foam is injected.
With refrigerator freezers the fans in the more expensive models also run all the time to circulate the air, and generally fail fast, as they are run in a very harsh environment, with water droplets running through them in the fridge side, and ice in the freezer side. Defrost in the fridge and freezer is done with a heater element by the coils, so that frost is heated up and melted back to liquid, and this then travels down a heated tube to the top of the compressor, where it collects in a pan, and the heat of the compressor evaporates it. Cheap units the heater runs when the compressor does not, but is low power, around 10W to 30W, so does not put much heat in the cavity.
When you buy commercial units your efficiency takes a dive though, as convenience in getting stuff in and out, along with having either glass doors with heaters so they do not mist up, or no doors at all, is the driver. However those you can repair, as they are expected to last 20 years or more in service, unlike a domestic unit.
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Funny thing is those are not common by me, the electronic ones, which use a 48V relay, and a resistor to drop the excess voltage, and a diode as rectifier, are common. They use a 12V zener diode to get power for the 555 timer used as control, and, because of ROHS saying no Cadmium containing things, they instead use a photodiode as light sensor. 555 timer drives a transistor or small triac, that shorts out the relay coil, to turn the lamp off.
Then you get the more complex ones that the street lights use, where the entire electronics is contained within a IC package, made from clear epoxy, that has the photodiode, amplifier and signal conditioning inside on the small silicon chip, and then this controls a thyristor that operates a 20A relay on the board. Note they also have to withstand all faults, so have a large MOV device across the mains input, 480VAC rated withstand, so that they will still survive and operate even if the nominal 230VAC mains has a fault and goes to 400VAC instead. Residential ones use a 275VAC MOV as protection, the last time there was a phase loss by me that got very unhappy, and blew the cap off the photocell, practically getting it into orbit. Not really going to protect, just clamping voltage to protect the wiring, and trip a breaker as it fails short.
Incidentally the street lights, for the most part, come with the photocell socket integrated in, as it is cheaper to make all of them the same, and supply instead a special shorting photocell, which has inside it only a 16A fuse and a 480VAC MOV across the output, so that there is still fuse protection when used in group applications, and the MOV clamps lightning strikes on the line down to a level the ballast and starter, or the LED driver for new ones, will probably survive, and, if not, disconnect the fixture. Most common by me are GE, Siemens and Royce Thompson as photocontrols, with Osram and Phillips (branded as Beka) also having a share, depending really on who won the contract for supply for a particular year.
You mostly see Osram or Phillips lamps though, as the most expensive part is the maintenance, and cheap junk lamps fail fast.
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USA missing a socket that is not flimsy. Rest of the planet uses some form of RCD on all socket outlets, USA only in the kitchen and bedroom, perhaps. Here RCD on all socket outlets, and when you do any sort of upgrade from whatever was there when installed to the original spec, gransfathered into the regulations as can comply to the spec as built originally, the only change is that all outlets have to be protected with a RCD, and all light fittings must have a ground connection. You can keep the knob and tube wire if it is still good, keep the rewireable ceramic fuses if you can find the fuse wire, keep the 5A socket outlet with no switch on th baseboard, and even keep the gutta percha wire in the steel conduit, just if you replace a socket outlet to get a 16A plug to fit you probably will be rewiring the whole house to get the RCD not to trip from the leakage in the old stuff.
Yes I lived in a house with an extension, powered off the original overhead bare wire to the fuse box in the kitchen, with the meter there, but the new section had a breaker, and a RCD and individual breakers in a modern panel.
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By me LPG is common, and a growing thing, seeing as it works when the power does not, and also the cost is both regulated, and also on par with electricity. I have a gas lamp, which also doubles as room heater in cold weather, and yes I have used it to make coffee at times, especially when camping, when I would wake up, turn on the light, and put the pot on top to make the morning brew, drinking before getting out into the cold.
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That Galanz fridge will fail in around 5 years, because they use cheap steel pipe for the evaporator and condenser lines, which are taped to the walls inside and outside, before the urethane foam insulation is blown into position to hold it there. This pipe is going to rust through, because of water condensing on the insulation, and wicking into the gap between the pipe and insulation, and then rusting the pipes through. Normally the pipe rusts through near the entry points in the foam, but you cannot replace the pipe without removing the insulation, and it bonds strongly to the plastic and steel.
The pipe used is cheap unplated steel pipe, with only a thin coating of varnish on it, because the adding of a zinc plate, to keep it from corroding, would mean they need to have an extra assembly step to sand off the coating at the ends, where they braze it to the fittings for the compressor and drier. Takes an extra 5 minutes on the line, so will not be done, just put the cut ends in place, add the acid based flux, and use an induction heater to heat it up and then apply the braze to it. also you can see they do not remove the flux residue, just a quick spray of paint to attempt to keep it from corroding. Funny thing is the compressor will last easily 20 years, even though it is made with CCA wire, and is filled with mineral oil over any other, as mineral oil will move properly through the system with the R600A refrigerant.
Thermostat works on the coil itself, fed through a piece of plastic tube, to be held against the suction line before the compressor. Thus it will only turn off when the cooling is such that the suction to the compressor is coming back at the evaporator temperature, around -10C, and thus saying there is no more heat load there.
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You do need to insulate those pipes, and also look into adding an extra layer of insulation on the tank itself, as most of the energy loss comes from the pipes conducting heat away. A well insulated tank will easily hold water hot for 5 days, as I saw when the power was out recently for 4 days, and the breaker for the timer had tripped due to the overvoltage spike causing the MOV surge arrestor to kill itself to protect the timer. Only noticed the water was getting cold after 3 days of power being back, and went and replaced the MOV and turned the breaker back on.
As the tank is rated for a 2kWh static loss per day, off the shelf, i had added an extra 2 layers of insulation to the tank, and had also added another thick insulation layer to the piping for the tank, both the hot and cold water, plus the safety overpressure line, as that copper also will conduct heat. Made a big ball of insulation there with the tank in the middle, getting rid of the 2 big heat loss areas, the pipes and the element cover. Electric bill is now a lot lower just from that, as cooking for a long time has been done with gas. Tank is also on a timer, only coming on for a half hour a day to make up losses, and it really only needs 15 minutes to make up for water use, but because of rotational load shedding times, it is set for either side of the time boundary, so is on from 01H45 to 02H15, despite there being no TOU reduced tariff by me.
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Had the exact opposite problem, first CD recorder was HP external, driven via parallel port interface. Had to write it at only 1x speed, otherwise you made an expensive at the time coaster. Later on stripped the case from it, found it was a plain jane HP SCSI drive inside, so moved it into the PC case, and got a longer SCSI cable for connecting it, though still with the passive terminator. That way got it to run at it's full 2x speed without buffer underruns.
Then had a Benq? brand IDE one, which would go all the way to 16x speed, and which had underrun buffer protection as well, so any speed would work.
In general used Verbatim media, found an old box of the ones burned in 1998 or so, and they all were still readable, at least before they had a 30 second bulk erase in the microwave oven.
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Ionisation detectors are best when installed in bedrooms, and the optical are best everywhere else. the faster response is a big benefit, and the only contra indication is for those who smoke, where both types will go off with false alarms regularly. The 10 year life is because of contamination, there is a slight airflow, and this with time results in a thin film of debris being deposited on all parts of the sensor and the board, which does eventually result in false alarms. Not the electronics degrading, or the source becoming too weak, but that you need to strip down the sensor to it's component parts, and thoroughly clean them of all contaminants, then dry, and reassemble. Just the labour cost alone will be more than the cost of a new sensor, though the ones that are used in commercial applications are much longer life, simply because they are designed for the cleaning to be done, and thus are a lot more expensive to manufacture.
Incidentally the amount of radioactive material in one of the ionisation detectors is very low, about equal to a few kilograms of coal, and, unlike the coal dust, it is well confined, not emitted into the atmosphere.
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Remember the original town gas was formed by taking coking coal, and then burning it while introducing live steam into the sealed chamber, so the red hot coal would as well act as a catalyst forming on the one side carbon monoxide, and also hydrogen, giving you extra boost for the gas stream. The CO was toxic, and the H2 was very much explosive, so it only took a small leak in an enclosed space to get the H2 level past the lower explosive limit of 4%, and thus have the explosion when there was either a spark or a hot surface. The CO was just as deadly, odourless, colourless and would leave the person dead in minutes, with no signs of distress, other than the bright red blood, even hours after death. As well small doses would lead to sleepiness, and thus you would not leave the leak area till it was too late, plus the gas does not trigger any sort of body response, like CO2 does.
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@alexatkin Race to the bottom price wise, meaning they cut corners on every part inside. If a part is 0.001c cheaper, but will only last 1000 hours, it will be used instead of the part that lasts 10 000 hours. Same applied to every part, including the light emitting part, where the current is so high you get appreciable lumen degradation within 100 hours, but the initial spec is still met, and lifetime is slashed.
LED the same, you get all sorts of claims for 100k hours, but the actual LED units will never be run at the rating, instead run at 5 times the 100k hour current, and run so hot that they are just short of melting themselves free of the board. If you are lucky they will do 2000 hours of running, as the manufacturers know almost nobody actually writes the install date on a lamp, and keeps the invoice (printed on thermal paper that fades to invisible in 6 months as well) to claim for the failures, plus the QC on them is essentially zero in the plant, just a check the unit is assembled externally before putting in the box.
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