Re: (ET) Converter losses

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

> I have been considering rebuilding the controls on an E20 ... 
> with newer technology, and have some questions:

Allan, I don't yet have direct experience with adding transistor control 
to an ET.  I've looked into it, though, as it's one of my long term 
projects.  Here's how I see it right now:

> 
> 1. Has anyone attempted this with a 36V system?  I'd rather not convert 
> my
> tractor to 24 or 48 if I don't have to.

There are thousands of 36v golf cars running Curtis and other transistor 
controllers.  No problem.

> 
> 2. How much power loss is there in using a converter [solid state 
> controller] for motor control? 

Very little.  Voltage drop across modern devices is a few hundredths or 
tenths of a volt.

> 
> 3. Who makes appropriate controllers and how expensive are they?

Curtis controllers are easy to find.  A new Curtis 1204-001 (typical golf 
car controller, 275 amps [1-minute rating] max, 24-36 volts) would be 
around $300, if I remember correctly.  There are some bargains in rebuilt 
Curtis controllers at 

     http://www.Wilde-EVolutions.com/PriceList.htm

That could take you down to about $200.

Note that none of these controllers provides field control.  You could 
retain the resistor field control, though, since it wastes little power.

> 
> 4. Has anyone considered using an AC drive motor with an appropriate
> converter?

This a costly option, well into the thousands of dollars.  For ET and 
similar applications, DC motors are probably more practical.



David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1979 General Engines ElectroPed 24vdc
1974 Honda Civic 96vdc
1970 GE Elec-trak 36 vdc