Motor Rewind Question
Motor Rewind Question
(OP)
Had a 2000 HP 2300V 3600 RPM WP2 motor rewound say 4 months ago. Motor age is approximately 40 years old. The motor ran for 4 months after the rewind before it tripped due to a stator fault. Found that that the fault occurred from a finger that was holding the stator laminations had come loose. Is it unreasonable to consider that the rewind shop should have checked all fingers during the rewind? Considering that there are say maybe 1500 fingers on the stator holding the laminations together, is that reasonable?.





RE: Motor Rewind Question
Muthu
www.edison.co.in
RE: Motor Rewind Question
RE: Motor Rewind Question
RE: Motor Rewind Question
What guarantee does the winder shop have? A minimum of 12 months is common. Many have more.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Motor Rewind Question
Muthu
www.edison.co.in
RE: Motor Rewind Question
Pictures of the failure tell a story the written word cannot compete with.
Share some photos.
John
RE: Motor Rewind Question
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Motor Rewind Question
RE: Motor Rewind Question
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Motor Rewind Question
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Motor Rewind Question
It looks as if there are spring clips to exert some pressure on the laminations.
I suspect that during the rewind this may have been used as a fulcrum for a prying tool and bent and damaged.
I see that one of the other fingers has been bent.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Motor Rewind Question
Muthu
www.edison.co.in
RE: Motor Rewind Question
Muthu
www.edison.co.in
RE: Motor Rewind Question
The picture fails to show the area of failure. Smoke charred coils are a result of a failure, but the photo
does not show where the so called “finger’ penetrated or caused the winding damage.
That's what the audience here needs to see.
I’m somewhat skeptical of a stator tooth support coming loose. I’ve seen lost screws in stators playing havoc,
and pieces from the rotating member coming apart causing a big mess, but stator teeth and their associated
components are very robust stationary items. They are hard enough to separate/fix during “hot spot” repairs.
Additionally, a stator that has been previously repaired more than once over its entire service life can be minus
all kinds of minute details that play little to no roll in their effective operation.
How does one know the so called loose part was even there to begin with?
It’s of course highly suspect that something occurred during the repair process that may have contributed
to the short lived winding repair. “But”, so far I don’t see the evidence to authenticate the theory.
Do you actually have the broken or separated tooth component in hand? What does that look like?
John
RE: Motor Rewind Question
As a suggestion:
The pre-wound coil was a little to narrow.
A tool was used to spread the coil slightly to place it in the slot.
The finger was used as a fulcrum for the prying tool.
The finger was bent or broken at that time.
Because the coil was slightly too narrow, there was more than normal pressure against the side of the slot.
A combination of the vibration of the unrestrained end lamination and the side pressure of the coil led to the failure of the coil.
Near the edge of the picture we see a bent finger, bent in a direction consistent with being used as a fulcrum. I believe that this supports my theory of narrow coils and pressure applied to the fingers during assembly.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Motor Rewind Question
It seems a very bad work if after only 4 months the winding head looks like this .
Good luck
RE: Motor Rewind Question
Muthu
www.edison.co.in