Re: (ET) What was that crash?

["David Roden (Akron OH USA)" <roden ald net>]

I always open the main disconnect when the tractor is parked.  I can do 
this 
since I charge with three external 12v chargers instead of the onboard 
charger.  

I haven't looked into it, but it seems to me it shouldn't be all that 
tough  
to rewire the onboard charger so it doesn't go through the disconnect.

That said, it's hard for me to understand how the tractor could start 
itself.  For the L1 to pull in, you have to have the key on, the seat 
switch 
down, the brake up (doesn't apply to this one?), and the speed lever 
advanced.  That's 3-4 switches that would have to fail.  Doesn't seem 
likely.  Is the seat switch definitely working?  Are you sure you had the 
key off?  I've accidentally left mine on a few times.

Barring such unlikely situations, the contactor would have to be at fault 
here.  Typical contactor failure modes are that the coil opens and it 
won't 
pull in, or the contacts weld and it won't shut down.  I have never heard 
of 
a contactor closing on its own.  The only reason I can think of would be a 
badly weakened return spring. 

In this case, it's a safety issue.  I wouldn't fool with it -- change the 
contactor, even if it seems OK now.  Perhaps even add a redundant one 
somewhere.


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea 36vdc
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