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Re: (ET) Motor trouble
Remember, you should have reduced voltage at starting across the
armature because both resistors are in series.....
L closes at start, then 1A, then 2A....check progression...then, field
weakening starts.
If you are getting 36V at start, the field is not getting power or is
bad.....
A new motor is not cheap....a GE authorized shop is up in Auburn
(assuming you're in Ithaca NY)..
B & F Electric Motors, Inc.,
1593 Grand Avenue
Baldwin, NY 11510
Phone/Fax:516-223-5511
...Walt
-----Original Message-----
From: Steve Gaarder [mailto:gaarder ecovillage ithaca ny us]
Sent: Monday, January 26, 2009 11:50 AM
To: Konstanty, Walter (GE Indust, ConsInd)
Cc: elec-trak cosmos phy tufts edu
Subject: RE: (ET) Motor trouble
I did check the armature volts - full 36 V. I'll check the field just to
be sure. And no, I don't presume to open up the motor myself.
Unfortunately, my local electric motor guy is out of business, so it
looks like I might have to send it somewhere. Any suggestions? Or
should I just get a replacement?
thanks,
Steve Gaarder
On Mon, 26 Jan 2009, Konstanty, Walter (GE Indust, ConsInd) wrote:
> You should still check the field volts when started.
> Also, armature volts. It may be lack of L contactor pickup.
> Brushes usually don't disconnect at once but it could be. You need to
> pull the motor apart to inspect/replace them which is not all that
> hard but putting it together takes some skill as you have to assemble
> the motor endshield while pulling the brushes back to move them far
> enough apart to slide the rotor in. I've pulled them apart, blown
> them out, inspected and replaced brushes.....but I've also had 30
> years at GE working on them.
>
> If you have a small local shop, it may be better for you to take it
> there and watch them do it....ask for a quote or fixed price to
> check/inspect....don't let them hi-pot the windings.
>
> Make sure the control is not the problem first unless you want to
> check the motor out anyways.
>
> ...Walt
>
> -----Original Message-----
> From: Steve Gaarder [mailto:gaarder ecovillage ithaca ny us]
> Sent: Monday, January 26, 2009 9:36 AM
> To: Konstanty, Walter (GE Indust, ConsInd)
> Cc: elec-trak cosmos phy tufts edu
> Subject: 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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>