Re: (ET) Varistor Across Motor Field???

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

From:                   "R. Barnes" <rfbarnes nwlink com>


> Do you know the size and voltage rating of the varistor ? Is this a metal
> oxide varistor (MOV) like they use in surge suppressors? What is it's
> purpose on the Elec-Trak?

I took a look at my E15 tonight.  There is a device perhaps 3/4" to 1" in 
diameter on card #3, as you describe.  It's brown and does resemble an 
MOV.  Unfortunately, there are no markings at all on mine.

Presumably it's there for transient suppression.  I suppose the field 
might generate some peak back EMF that could be unhealthy for the 
electronics on card #1.  Just a wild guess.

If I were in your position, I think I'd look into ditching all the 30 
year old controls and replacing them with a modern transistor controller. 
 I haven't done this yet with my ET because I'm not sure the motor has 
enough inductance to make a typical golf car series motor controller 
(such as one of the small Curtis controllers) happy.  

Has anybody on the list successfully installed a transistor controller?  
What brand and type did you use?  Does it work smoothly and reliably?


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1979 General Engines ElectroPed 24vdc
1974 Honda Civic EV 96vdc
1970 GE Elec-trak E15 36vdc