RE: (ET) chargers

["Bob Murcek" <RMURCEK geisinger edu>]

Just a comment related to using a PWM controller intended for a series 
motor for an ElecTrak.  I think all the Electrak motors are compound 
wound, which means they do have a "small" series field at least.  Perhaps 
this is adequate to meet the inductance requirement for current limiting.

>>> "SolidTech" <SolidTech qwest net> 5/1/2002 6:53:42 PM >>>
OK... I know this has been discussed before, but there's a 36V motor speed
controller on eBay as well.  It is a PWM model.  I have an E-15 and it has
the separate connections for the armature and the field (to enable field
weakening in the higher speeds).  The controller only has two connections 
(+
and -) for the motor.  So, to use this type of controller what happens to
the field weakening - just not used?  And if that is the case, then is the
top speed just not as fast?  What effect would that have on the lower 
speeds
in terms of power production - better or worse?  Could an "overdrive" be
added that would engage some field weakening once the highest speed was
reached on the controller?

thoughts?
- - joe
E-15 in Colorado

-----Original Message-----
From: owner-elec-trak cosmos phy tufts edu 
[mailto:owner-elec-trak cosmos phy tufts edu]On Behalf Of Neil Dennis
Sent: Wednesday, May 01, 2002 2:59 PM
To: Elec-trak
Subject: (ET) chargers


See on e-bay a 36 volt automatic charger and some other stuff by asking
for 36 volt on search.  Includes a "super" mower.

wombat - just finished mowing the lawm for first time, some about 6"
high, and from the sound may need a new bearing in a mower motor.
Haven't touched it in about 20 years so no complaints.