Author Topic: Armature rewinding  (Read 9507 times)

Offline Pete.

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Re: Armature rewinding
« Reply #25 on: November 27, 2019, 06:57:22 AM »
Well done John!

In my youth I had an apprentice job building those stacks of laminations and winding small motors but I never had to do a rotor because they were special (at the time) brushless dc motors. Winding them is just a matter of patience and being methodical, as you have found. Encapsulating the windings is also important so they don't rub together in use, and hang them vertical afterwards whilst the varnish dries so you don't upset the balance too much.

Offline John Rudd

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Re: Armature rewinding
« Reply #26 on: November 27, 2019, 07:09:12 AM »
Pete,
Thanks for the tip on varnishing the turns and rubbing.... I intend to get some 'electrical laqcuer' for completion...But didnt realise it had a primary function of retaining...

Does your expertise stretch to 'terminating the coils to the comm segments' ?
Reason I ask is, if the coils are terminated round the comm, does the direction matter? Mine runs the wrong way, so I guess I should have connected up the opposite way?


I have another armature to rewind for a Stanley Fatmax hammer drill,( the field coils are burnt out too..) but a job for another day...
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Offline Sea.dog

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Re: Armature rewinding
« Reply #27 on: November 27, 2019, 08:05:22 AM »
The direction of winding is the critical part. You could, at a push, reverse the tails of every winding, but that's very much a bodge, crossing wires everywhere. Easier to swap the brush leads in my opinion.

Offline John Rudd

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Re: Armature rewinding
« Reply #28 on: November 27, 2019, 08:58:40 AM »
The direction of winding is the critical part. You could, at a push, reverse the tails of every winding,

I think thats how it was wound originally, but as the coil tails were buried in epoxy, it was difficult to tell....

The field coils remain as they were originally......

I think more research required before proceeding with another rewind..... :scratch:
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Offline Pete.

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Re: Armature rewinding
« Reply #29 on: November 27, 2019, 07:01:08 PM »
Yes the turns direction is crucial as said. I can't help with questions about commutators because of course those brushless motors didn't have them. One thing I did learn from reading is that brown coloured commutators is normal and you shouldn't clean them up shiny just because they look brown.

Offline John Rudd

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Re: Armature rewinding
« Reply #30 on: July 29, 2020, 08:16:50 AM »
So to update this, after several ( maybe should read many,many) rewinds I got it down but its not a complete success!
Turns out ( no pun intended...) that the shaft is bent...

I have learnt that there are different ways of terminating the coil ends...This is called Retrogressive or Progressive winding...
Then there is lead throw and coil throw...
Lead throw is how the coils are terminated, relative to the comm segments.
The coil throw is dependant on the number of armature coil slots and the number if brush pairs....

It is 'normal' practice to nite all this info prior to embarking on a rewind!
Fortunately I was lucky to find a mentor who was willing to tutor me.

So for now, the armature is sitting in the workshop awaiting further attention....( a get round to it job..)
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