(ET) Using 4QD controllers

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

This is forwarded with permission from a message sent to me by Christopher 
Goddard.  He was responding to my post about using a 4QD  controller in an 
ET.

= = = = = begin forwarded text = = = = = 

I have used many 4QD controllers (very commom in UK) to power separately 
excited motors.  The simple way is to use the brake drive output to drive 
a 
relay which switches the field on. The brake drive is energised just 
before 
the controller output comes on and drops out just as the output drops to 
zero.  

With a 4 quadrant controller this gives smooth control in drive and regen 
braking.  I suppose  a cheaper solution would be to use a 2 quadrant 
controller and achieve reverse by simply reversing the field current with 
relays.  

I also have an International Cadet 81 which I converted some time ago to  
electric power with an E tech motor and 36v 200amp 4QD controller.  Works 
very well but have doubts about the transaxle strength!  

A few years ago I built from scratch an electric tractor running a Lynch 
motor at 48v and 300amp controller.  It is very lively and capable.  
Really 
hard work, shame it seems to have been taken over by 7 year old son!!  

= = = = = end forwarded text = = = = = 

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
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Thou shalt not send me any thing which says unto thee, "send this to all   
  
   
thou knowest."  Neither shalt thou send me any spam, lest I smite thee.    
  
       
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =      
  
 
Est. yearly US cost to safeguard Persian Gulf oil supply: $50 billion      
  
       
Est. 2001 value of US crude oil imports from Persian Gulf: $19 billion  
                                -- Harper's Index, April 2002              
      
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =