Re: (ET) What was that crash?

["Christopher Zach" <czach computer org>]

I can understand closing a relay, but how can you manually close an
interlock like 1A or 2A? The three switches together (AND) provide power
directly to the 1A interlock coil, which lifts up, latches in, and provides
the big power to things like the motor.

They are sealed units, and if my observation is correct, they are mounted 
so
that if the spring were to fail gravity would keep them from jumping up and
engaging. If you put your tractor upside down, they might fail, but
otherwise they seem to be designed to fail open.

Chris

----- Original Message -----
From: "Hazen, Dwight L" <hazen indiana edu>
To: <elec-trak cosmos phy tufts edu>
Sent: Saturday, June 08, 2002 9:32 PM
Subject: RE: (ET) What was that crash?


> The safety interlock switches only applies power to the relay coil if the
> three switches are in the safe to run mode. That is you are on the seat,
key
> is on and the brake is off.
>
>  If you manually close the relay or damage the contacts the tractor will
run
> with out the three switches in the safe to run. This is one of the 
> reasons
> why all electric vehicles have a master disconnect switch.
>
>   Dwight
>
> -----Original Message-----
> From: JimLuckett aol com [mailto:JimLuckett aol com]
> Sent: Saturday, June 08, 2002 3:49 PM
> To: roden ald net; elec-trak cosmos phy tufts edu
> Subject: Re: (ET) What was that crash?
>
> In a message dated 6/8/02 1:48:35 PM Eastern Daylight Time, roden ald net
> writes:
>
>
>
>
> .  Is the seat switch definitely working?  Are you sure you had the
> key off?
>
>
> The key was not in the slot, much less left on.  The seat switch works.
> First thing I tried to shut it off was to put key in slot and rotate it
back
> and forth, with no effect.
>
> Thanks for your thoughts.
>
> Jim Luckett
> 120 Avebury Circle
> Boxboro, MA 01719
> 978 263 7598
> Fax 978 263 0384
>