Comments by "spaceflight101" (@spaceflight1019) on "Technology Connections" channel.

  1. Years ago at Elrama Power Station I was sent to see why the parking lot lights weren't working. The contactor was full of stink bugs.
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  2. At Cheswick power station we got a frantic call from the barge unloader that the barge mover wouldn't shut down. We killed it with the disconnect, then found that the contacts on the contactor were welded together.
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  3.  @Lemon_Inspector  Always have a Plan B too.
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  4. Power stations have a wide variety of contactors, powering everything from 208 volt lighting to large motors. Small ones, for 480 volt use, typically have a control transformer that converts the 480 to 120 for the controls. Large ones have two latching solenoids that are powered by the plant 135 volt DC system.
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  5. I can tell you many power station stories. When a "medium voltage" contactor, 2300 or 4160 volts failed closed, an operator put on protective gear (think bomb disposal technician) and attempted to operate the mechanical trip mechanism with a long pole. If that failed, and it did, the only option was to turn off everything else on the bus and trip the bus feeder. Once that was done it was my job to remove the defective contactor from the motor control center. All of them have large springs inside, about the same size as the suspension spring on a car, and the energy they contained had to be discharged safely. Usually, once you discharged the spring the contactor was easily removed.
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  6.  @dogwalker666  You would have loved the barge unloader at Elrama. It was a clamshell bucket powered by a multispeed lift and trolley motor system that looked like an angry amusement park ride with contactors snapping and arcing and steel cables whipping back and forth. There was only one man capable of unloading seven barges a shift; nobody else developed the rhythm.
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