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I Forge Iron

How to remove electric motor stator?


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Hello,


We got on old metal cutter and the motor is "burner". So we decited to re coil it.

Problem is how to remove the motors stator? It is there pretty tight and can't see any method of attacment.

In pic.2 are small gaps in outer ring ond you can actually see trough other side from those gaps.2_(640x480).thumb.jpg.a7ef17348def01d7bc

1 (640x480).jpg

3 (640x480).jpg

5 (640x480).jpg

4 (640x480).jpg

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If that isn't a beast. At this stage of the breakdown I'd consider sending it to the rewinder as is, I would suspect that your fighting melted reson and varnish from the windings. This assuming any one crazy enugh to tear it down this far has theroly inspected the case for countersunk screws under the paint. I would also send the comintator and brush holders allong to have a second set of eyes inspect them. A DVOM sertainly can find any openens and shorts, but an experianced eye and a growler dosen't hurt either.

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which part of the world are you in?

if in england I may be of some assistance.

 

Charles, that type of motor does not have brushes and a commutator and there will be no countersunk screws under the paint, the outer case is heated to get it to fit and then cant be removed

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which part of the world are you in?

if in england I may be of some assistance.

 

Charles, that type of motor does not have brushes and a commutator and there will be no countersunk screws under the paint, the outer case is heated to get it to fit and then cant be removed

​Finland. It only takes couple hours to fly here...

 

We came to same conclusion here. Let's heat up the beast and remove the stator.

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you will need the stator cold and the casing hot, also record the exact position and orientation of the stator, turns, direction thickness of each winding and how they are interconnected, any of this wrong and it wont work and may be very dangerous.

I presume you have rewound motors before and have the equipment and knowledge needed to do this

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Getting to do that is relatively easy with a large induction heater.:D I had thought about doing a similar job on one or two of my own motors, I even bought a book on rewinding small motors, now that I have the book I've decided to retain my 'good business relationship' with 'my' rewinding mate.

Edited by ianinsa
'xx@#%&' spelcheck
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I love watching DIY's like this  keep us posted

​me too

from the questions I dont think this person has very much experience of rewinding such motors, I would not attempt it!.

I know some of the basics but would leave it to the pro,s or replace the motor by modifying one to fit

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Its funny that some of the best armour makers freely share their knowledge and help with people wanting to avoid paying the price for good armour for medieval/renaissance reenactment use.  After an attempt or two the prices start looking rather *cheap*!

I try to find an old motor repair place when I need motor help; preferably with some old codgers that have been rebuilding motors for 40+ years...

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Whell we have our lovely and trustworthy faces posted on here Steve, tho I admit mine resebles an old west mugshot and yours a wanted poster skech ;-) 

​my only other photo had a number bar across the bottom, even the side views too, and I dont look  good in an orange jumpsuit

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  • 2 weeks later...

I managed an electric motor rewind shop for a year and helped out occasionally with the rewinds. Motors seem really simple but there are HUGE variations in how it all comes together.  Do it wrong and it's a fire hazard.  Winding arrangements alter the torque, speed, direction, horsepower, and current draw of the motor.  Subtle changes are not at all easy to define mostly because you can't get the windings loose until the varnish is burned off.  It takes a very practiced eye and a hefty amount of reference material to define what you're looking at.  We had a huge library of reference material and yet we still encountered occasional "mystery" motors.

Beyond all of that, burning out the resin/ varnish requires a furnace built for the task.  Out here, that means an after burner on the stack and regular EPA inspections.  Depending on what it's made of, varnish can be incredibly toxic when it's burned.  Very often the entire motor assembly is placed in the furnace.  I would very much discourage you from taking it apart.  Motor rewind shops will have all the necessary tools, equipment, and knowledge to fully refurbish the motor.  Bearings are an enormous variable that often drive upwards of 30% of the cost.  Very expensive bearings are irreparably damaged through mishandling.  Torches can melt Babbitt bearings, commutators, and brushes.  Stators can be made of oxidized steel laminations that are deceptively easy to damage.  Capacitor start motors can hold deadly charges for years after the motor is disconnected from power. 

Also, when the motor is re-installed great care must be taken to avoid misalignment.  We often think hulking cast-iron enclosures are bomb-proof but they're not.  Larger motors can wear out their bearings in short order if the mounting feet aren't perfectly level, and evenly torqued down.

I would strongly recommend you take the entire thing to a rewind shop.

 

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  • 2 weeks later...

In about 90% of the motors we rewound, the stator is left in place and the entire housing is burned out in the kiln.  The old windings are cut and the copper gets pulled out.  The new windings go in through the slots and are held in place with a sheet of Nomex folded to "cap" the slots, then the entire thing is dipped into dielectric laquer and kiln dried.

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