In article ,
Jeff Layman wrote:
On 04/01/2021 14:28, Dave Plowman (News) wrote:
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.

Maybe Lucas had surplus in stock and decided to "second-purpose" them.

I'm more interested in the large capacitors. I can't think of a more
hostile environment for a capacitor than a car engine compartment,
particularly if it is an electrolytic to get that long pulse. Or was the
control unit in a cooler place?

It's situated inside the rear wing, so temperature depends on the weather.

I doubt you'd use surplus stock on a design hoped to sell many thousands?

--
*Those who live by the sword get shot by those who don't*

Dave Plowman London SW
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