Motor winding help needed bldc

Electric Motors and Controllers
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jacobbloy   100 W

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Motor winding help needed bldc

Post by jacobbloy » Feb 06 2016 6:50am

I'm just wondering if some one here can help! Iv been working on small hub motors for a skate board, I dont want to just go an offe the shelf convention, I have recently changed for 14pole to 24n28pole but my winding seems to be off.

I have wound it in a Wye configuration it seems to not be 120deg

These are my test results.

Ps. I can add square wave if it's needed.
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major   10 kW

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Re: Motor winding help needed bldc

Post by major » Feb 06 2016 11:39am

jacobbloy wrote:I'm just wondering if some one here can help! Iv been working on small hub motors for a skate board, I dont want to just go an offe the shelf convention, I have recently changed for 14pole to 24n28pole but my winding seems to be off.

I have wound it in a Wye configuration it seems to not be 120deg

These are my test results.
After the last winding question thread, I'm almost afraid to rely :wink:

Did you change the magnets to go from 14 to 28 poles?

jacobbloy   100 W

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Re: Motor winding help needed bldc

Post by jacobbloy » Feb 06 2016 12:18pm

Yes I did
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major   10 kW

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Re: Motor winding help needed bldc

Post by major » Feb 06 2016 2:34pm

Did you wind it like this?
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Lebowski   1 GW

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Re: Motor winding help needed bldc

Post by Lebowski » Feb 06 2016 3:00pm


jacobbloy   100 W

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Re: Motor winding help needed bldc

Post by jacobbloy » Feb 06 2016 7:53pm

I just ran the motor in a jig at about 714rpm

I tested the voltage on each phase wire, the yellow phase group is 4v below the other 2
Phase A 8.14v, phase B 4.7v, phase C 8.14v.
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Lebowski   1 GW

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Re: Motor winding help needed bldc

Post by Lebowski » Feb 07 2016 3:06am

A short via the stator iron ?

jacobbloy   100 W

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Re: Motor winding help needed bldc

Post by jacobbloy » Feb 07 2016 3:25am

Lebowski wrote:A short via the stator iron ?
Mmm that is an idea but it could course more then just voltage drop.

I was suggested that one phase is terminated backwards. This will cause it to 'fight' the other two when you spin the motor.

One way to find out - sequentially give each pair of wires some amps (a power supply or a few D cells in series is good) and mark, relative to a stationary thing, where the motor moves to. For example, power A-B, then A-C, then B-C, then B-A, etc... for the full six states.

If your marks are evenly spaced, then there problem is somewhere else, but if they are grouped in two areas, a phase is terminated wrong. And it's 99% the B phase since it's non intuitive when you finish winding the A-phase that you need to move 120 degrees over to "start" it.

But I still need to test this.

major   10 kW

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Re: Motor winding help needed bldc

Post by major » Feb 07 2016 7:46am

I'd remove the rotor and energize each phase seperately with DC. Then check polarity of each energized coil. Kinda sounds like you have one coil backwards.

jacobbloy   100 W

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Re: Motor winding help needed bldc

Post by jacobbloy » Feb 07 2016 9:35pm

I did a jumper to swap the small and long B phase wires, then I did the test on the jig and tested the voltage and they where all the same so I bit the bullet and tested the motor hoping my soldering was good enough and I didn't short any thing. (I hate soldering enamel wire)

I spun up the motors and the high current draw is gone and it's seems like the timing is know correct!

Thanks every one so much for your help! And I hope this finds some one els who has this problem.

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