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Newly coiled motor burnt out

cheryl

Jul 19, 2018
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We recently had a motor from our wood working machine recoiled. We paid over $1000 to have this done. We called the electrician to come and re connect it, the belts remained the same as they had been for the last 11 years, however the electrician could not get it to work. We returned it to the re coilers who informed us that the motor was now burnt out but that it was not their problem as it was working when it left them. It hasnt run as it didnt work, just puffed a bit of smoke when they tried to start it for a few seconds. How could this be possible?
 

Bluejets

Oct 5, 2014
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What opinion does your electrician have?

Perhaps he should be talking to the rewind people as he would have been the one doing all the necessary megger tests etc. before power up.

I prefer to do initial run up no load as motors can run backwards and for other reasons as well BUT that is just me.
 

WHONOES

May 20, 2017
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I agree with Bluejets, I would have run it up with no load to make sure it was Ok.
Is it 3 phase.
 

cheryl

Jul 19, 2018
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I agree with Bluejets, I would have run it up with no load to make sure it was Ok.
Is it 3 phase.
Motor is 1.4kw 3ph Our electrician suspects that the internal connections may have been wired differently to their original specifications, they tried it for no more than 10 seconds before returning it to the repairers. They deny any obligation in regard to this.
 

cheryl

Jul 19, 2018
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Motor is 1.4kw 3ph Our electrician suspects that the internal connections may have been wired differently to their original specifications, they tried it for no more than 10 seconds before returning it to the repairers. They deny any obligation in regard to this.
 

Bluejets

Oct 5, 2014
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Seems it would be an isuue for you and/or your lecky to sort out with the repairer.
I doubt there would be any further advice from others here.
 

WHONOES

May 20, 2017
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I had an issue with a 7.5HP 3phase motor many years ago that didn't want to run properly and got hot. I replaced the motor only for the new one to behave in the same manner. It turned out to be the contactor used to start / stop the motor. One set of contacts had burnt out so the motor was trying to run on just two phase and didn't like it.
 

Minder

Apr 24, 2015
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I had an issue with a 7.5HP 3phase motor many years ago that didn't want to run properly and got hot. I replaced the motor only for the new one to behave in the same manner. It turned out to be the contactor used to start / stop the motor. One set of contacts had burnt out so the motor was trying to run on just two phase and didn't like it.

Strange the O/L didn't detect that, normally it would not be on very long if single phasing.
M.
 

cheryl

Jul 19, 2018
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I had an issue with a 7.5HP 3phase motor many years ago that didn't want to run properly and got hot. I replaced the motor only for the new one to behave in the same manner. It turned out to be the contactor used to start / stop the motor. One set of contacts had burnt out so the motor was trying to run on just two phase and didn't like it.
The repairers state that the motor has probably collapsed due to collapsed bearing in drive spindle. Sparky tells us they believe internal motor conections may have been wired differently to their original specs. In their work shop it would only run in reverse to how it used to run, Its 3ph but wired to run on single ph, Steubnetz method. In other words no one is responsible for this, I dont have any technical knowledge so hoping to get an insight on who is correct. We're out of pocket for over a $1000 and now we have a new bill from the repairers to tell us the motor is burnt out.
 

cheryl

Jul 19, 2018
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The repairers state that the motor has probably collapsed due to collapsed bearing in drive spindle. Sparky tells us they believe internal motor conections may have been wired differently to their original specs. In their work shop it would only run in reverse to how it used to run, Its 3ph but wired to run on single ph, Steubnetz method. In other words no one is responsible for this, I dont have any technical knowledge so hoping to get an insight on who is correct. We're out of pocket for over a $1000 and now we have a new bill from the repairers to tell us the motor is burnt out.
 

Bluejets

Oct 5, 2014
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Forward or reverse 3 phase should make absolutely no difference as it is simply a reversal of phase sequence.

A bearing collapse certainly can do a lot of damage in a short period but something about this whole scenario just does not sit right.

Something that started as a simple rewind of a burn out has now escalated into a mass of problem areas.

Never heard of " Steinmetz Circuit" and had to Google it just to get the spelling correct.
I'm not surprised your lecky has hit the road.
Sounds to me like one source of you problems.

You do realise there are single to 3 phase converters that will do the job successfully......or for that matter single phase 2 hp motors....either can be managed by most leckys.
 

WHONOES

May 20, 2017
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Strange the O/L didn't detect that, normally it would not be on very long if single phasing.
M.
It was only on a large compressor some 30 years ago and wasn't sophisticated and had no overload detection.
 

Minder

Apr 24, 2015
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It was only on a large compressor some 30 years ago and wasn't sophisticated and had no overload detection.

Hmm... 7.5hp and no O/L, Tut Tut;)
BTW I did my apprenticeship in Oxford.!
M.
 

WHONOES

May 20, 2017
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Yeah I know. Tight arsed employer.
I'm located just to the west of Oxford. Beautiful city with a long history. What took you to Canada?
 

Minder

Apr 24, 2015
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city with a long history.

Doesn't everywhere in the UK have a long history!:D

I had a very good,well paid job that I liked as an Industrial Electronics Technician, married, two kids, a house.
Just felt like a change.o_O
M.
 

WHONOES

May 20, 2017
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Doesn't everywhere in the UK have a long history!:D

I had a very good,well paid job that I liked as an Industrial Electronics Technician, married, two kids, a house.
Just felt like a change.o_O
M.
Yes you are right, I was just being specific to the city. I was born a Londoner and came to the Oxford region 13 years ago via the south coast.

That's they way it should be, go where the mood / prospects take you.
 
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