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Re: (ET) Motor trouble

Thanks for the suggestions. The current draw is very small, so I figure that the problem is not the field. Also, the one time I had a field supply failure, the motor did turn, but ran fast with little torque. 

No smoke or any heating that I've noticed.
Could this be a problem with the brushes? Can they be changed without pulling the motor? 

thanks,

Steve Gaarder

On Mon, 26 Jan 2009, Konstanty, Walter (GE Indust, ConsInd) wrote:


Steve,
Basic motor troubleshooting:
- drive motor has shunt field (2 smaller wires)
- power must be applied to shunt field to run and voltage is stepped
with large contactors to the armature (2 larger leads)
- finger relay reverses shunt field polarity and motor direction for F-R
- if power gage is pegging and motor not turning, field is bad or
probably not getting power from relay (those finger relays are notorious
for sticking or arcing)
    check relays, sand connections, make sure they are working.
    Shunt field is approx 17 ohms
- VR-1 on card 3 (reddish disc) may also be burned up....it absorbs
voltage when relay reversed for direction

So, make sure field has 36VDC when starting....monitor field and
armature voltage.  If motor is bad, I'd suspect armature is shorted or
grounded and you'd smell it.  Pulling motor is not fun so check control
first which is 95% of normal problems on E15.

...Walt

-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of Steve
Gaarder
Sent: Monday, January 26, 2009 9:09 AM
To: elec-trak cosmos phy tufts edu
Subject: (ET) Motor trouble

Our E-15 is running intermittently.  There seems to be voltage on the
two large motor connections when it's not running,so I figure the
problem must be in the motor.  Am I overlooking anything?  If not, I
will pull the motor and take it to the local motor shop.  Is there
anything I should tell them about these motors?

thanks,

Steve Gaarder

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