In article ,
Harry Bloomfield wrote:
on 04/01/2021, Dave Plowman (News) supposed :
What the control unit does is provide a pulse about a couple of seconds
long to operate the solenoids, then back to zero. Even when the switch is
still made. Same as all, really.

I have seen large capacitors used as the power source for solenoids on
one car. Slow charging via a resistor, then fast discharge via the
solenoid when triggered.

Indeed - what I am curious about is the use of massive relays rated at
hundreds of amps to switch under 20. Obviously their coils have a much
lower resistance than a 30 amp one which would typically be about 150
ohms. So need much larger caps too.

--
*Rehab is for quitters.

Dave Plowman London SW
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