RE: (ET) Reversing E20 DA Motor Polarity

["Raymon R. Ellis" <rayellis direcway com>]

Bob Murcek,
Thanks for the response. I do not recall if the difference was noticeable
before the conversion. Next week I will contact the tech people for help. I
do know that there is a weak growl type hesitation when starting forward as
now configured and the top speed on the driveway is much slower going
forward than backwards. Compared to the double contactors reverse is too
quick and fast to be comfortable. Someone said the opposing armature shunt
built in the E20 motor is operable in one direction only. I reason that
polarity is important but I just don't know why or how. It's like looking 
up
into space and inquiring about the universe, I don't understand this thing.
Raymon

-----Original Message-----
From: Bob Murcek [mailto:rmurcek geisinger edu] 
Sent: Saturday, August 28, 2004 11:34 AM
To: elec-trak cosmos phy tufts edu; rayellis direcway com
Subject: Re: (ET) Reversing E20 DA Motor Polarity

I'm not the best source of info on this, but I'm a little confused about
what you mean and maybe others are also.

Before the conversion, did it run smoothly in forward and jumpy in reverse?
If so, and it's now the other way around, you could reverse BOTH the
armature and field connections to see if the jumpiness is polarity related.
(If you were to reverse only the armature or the field, the motor would run
in the opposite direction.)  Normally polarity wouldn't matter to a DC
motor, but if the E20 motor is as complex (opposing series field for speed
regulation) as mine, maybe polarity does matter.

It might be a good idea to have someone with an E20 schematic tell you what
the polarity of the connections to the armature winding were in the 
original
setup, duplicate that, then reverse the field connections if necessary to
get things going the right way.

If the thing was jumpy in the forward direction before the conversion, or 
if
you don't know whether it was jumpy before the conversion, it's possible
that there's a problem with the brushes that causes problems in one
direction; the motor guys could tell you what to look for...Bob
 

>>> "Raymon R. Ellis" <rayellis direcway com> 8/27/2004 5:51:13 PM >>>
Will a member, maybe Ralph, who has experience with the electronic
controller conversion of the E20, tell me the best way to change rotation
direction on the E20 motor? The original setup of the drive motor runs best
in one direction and is kind of jumpy in the other direction. Is it OK to
run the motor with armature cables reversed so that the smooth running is 
in
forward gears? The motor now wired in accordance with supplier provided
schematic is jumpy in forward and smooth as silk in reverse. The motor was
tested before the conversion using two 12v batteries and direction of
rotation was reversed by changing either the polarity of the field (F1 & 
F2)
or the armature (A1 & S2). A comment will be appreciated. Thank you. Raymon
Ellis




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