Re: (ET) field rev.

[Christopher Zach <czach computer org>]

Ferguson Apiaries wrote:
> I have a New Idea 15 that I converted.  Got fed up with the controls so 
> made my own.  I have a simple controller for the armature and 4 switches 
> hooked up to the original resistors for the field.  My question is when 
> I have it in high and least resistance to the field and put it in 
> reverse it just speeds up by about 50%, why?  Nice feature though.

As discussed, compound motor. This is designed to provide more field 
(and thus keep the motor from blowing up) as the load on the armature 
goes up.

However it does not reverse with the main field, and the result is that 
it counters the main field in reverse. This is why E20's lock out field 
weakening when going in reverse (and probably E15's too)

Chris