Re: Pre-charge resistor

["Lee A. Hart" <leeahart@earthlink.net>]

SteveB48@aol.com wrote:
> I seem to rememeber a "lively discussion" last time this came up but here
> goes. The Curtis manual states the main contactor should be controlled by
> a switch on the throttle.  Not a good idea?

It works fine as long as you have a precharge resistor. The contactor is
switching a "dry" circuit, i.e. negligible current and voltage, so the
contacts last for a million cycles. The purpose is to guarantee that
releasing the accellerator pedal turns the motor off even if the
controller fails "on".

But people don't like the "clunk" when the contactor pulls in and drops
out every time you operate the throttle. So they wire the contactor "on"
with the key, and (hopefully) have some other method to turn off the
motor in an emergency.

In my EV, I wired the second contactor to the brake switch. It thus
drops out whenever I step on the brakes. Far less "clunking", but the
motor will still be shut off in an emergency without the driver having
to do anything that they wouldn't naturally do anyway if the motor runs
away.
-- 
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen