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Discussion Starter · #1 ·
Still waiting on a few parts, (those top field wiring terminals which are earth terminals are only temporary placeholders, waiting on more terminals). All the wires hanging out the bottom are for a door switch and voltmeter. The panel is for headgate backup trip protection.
 

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Discussion Starter · #7 ·
Looks like it should have been a bit bigger.
You're telling me. Nothing I could do about it though.
What's that supposed to do? Does it assures the accumulators dump or something?
Just ensures being able to trip the headgate solenoid from the capacitor charge if there's a loss of power. The way the engineer has designed it is that if the PLC loses power, it drops out the output to the contactor in the picture, which disconnects the DC supply and connects the solenoid across the capacitors.
 

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To me this seems like a hokey way of doing it. Seems like the solenoid should be fail safe and close the gate on loss of power, or it should trip using the plant DC.
 

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To me this seems like a hokey way of doing it. Seems like the solenoid should be fail safe and close the gate on loss of power, or it should trip using the plant DC.
I don't know what the application is, but this could be a designed as "DC backup"? E.g., a lot of circuit breakers have capacitive trip as well as DC source, so you end up with double redundancy.
 

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I don't know what the application is, but this could be a designed as "DC backup"? E.g., a lot of circuit breakers have capacitive trip as well as DC source, so you end up with double redundancy.
I think that's exactly what it is. On a head gate going into a penstock (pipe feeding water into a hydro generator), you must have redundant systems that will maintain control of the gate at all times. So if the generator trips for some reason and you have to stop the water from spinning it, or the penstock bursts somewhere and you have to stop the flood or washout, but the DC power has failed, the back-up plan is this stored energy system dedicated to that one solenoid. It pulses the solenoid, which sets in motion a hydraulic operated gate valve that shuts off the water flow. It's a backup for the backup and it's a one-shot operation, but it can mean a lot in an emergency.
 

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Just a weird design. Every system I've seen is a spring-opened valves held electrically closed. Makes it fail-safe instead of relying on DC.
We're talking BIG valves here.
 
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