If you use the 2 pole switch 2 things can happen when the switch is switched:
thing no 1 - the engine doesn't stop (most likely a dynamo car).
thing no 2- the engine doesn't stop but the alternator light comes on
(diodes
fried in the alternator)
I have first hand experience of a 2 pole switch and both things.
With the 6 pole switch correctly wired, with the big resistor, only 1 thing
can happen, irrespective of what the engine or alternator rpm is - the engine
shuts down. When you re-set the switch and re-start the engine the
alternator light goes it and it works ok.
I'd look for a new speed shop.
Alternatively get the speed shop to throw the kill switch with an engine
running at 4000rpm and see what happens. As a licensed scrutineer of many years
experience I can assure that it's not unusual to have 2-3 cars a year that
carry on running with the switch thrown. Usually I'm the first scrutineer to
discover this because I'm the first one to have tested the kill switch with
the engine running.
A race car with no dynamo or alternator clearly only needs a 2 pole switch
but I'd still be looking for a new speed shop.
W e s l a k e 1330
In a message dated 17/10/2008 00:25:41 GMT Daylight Time,
mdrowe@optonline.net writes:
> The big resistor is there to stop the rectifier diodes in the alternator
> frying/self destructing when the switch is thrown with the engine running
>> at an
>> rpm above the alternator kick-in rpm. The resistor is a biggy.
This makes a lot of sense.
So what happens when you rev the engine up and turn off the key, which is
exactly the same situation? The alternator is alternating with nowhere to
dump the current. Does the ignition also have a shunt? Or is the
alternator already protected in some way that makes the resistor
unnecessary? If so, this is an "old mechanic's tale." My local speed shop
has never heard of a 6-pole kill switch. They just use an ordinary battery
switch with the alternator included.
Michael Rowe
'74 Midget
Long Island, NY
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