Hub motor phase wire problem

[Tukkis]

Hello!

i had been driving without any issues. And did change hub bearings. Now when the hub is open i tested continous of the phase wires.
Multimeter beeps if i touch the axle of the hub and one of the phase wires? Should it do that?

Hub is crystalyte 406 DD

-TukkiS

 

[amberwolf]

Depends. Is the motor plugged into the controller? And bolted to the frame? Or is it disconnected from everything and separated from the frame?

If the latter, then no, it shouldn't do that; it probably means that either a phase wire thru the axle has been damaged (usually at the axle exit) and is shorting to the axle itself, or a winding is shorting to the stator laminations.

If the problem did not exist before the bearing replacement, then axle wiring is the most likely culprit, as it could be damaged during cover removal or reinstall.


To find out *which* phase it is on, you would need to disconnect the Wye point between the phase windings inside the motor itself. Then each phase is independent and the short would only show up on the actual damaged phase.

To see whether it is a winding or phase wire problem, you would have to disconnect the winding from the phase wire, and test each. The one that's still shorted is where the fault is.



If the former, then it could do that if the battery negative wiring of hte controller is grounded to the frame, and the axle is grounded to the frame, and the test equipment's continuity / diode mode is capable of causing the FETs in the controller to conduct during the test, so that it's really seeing the battery negative conection thru the FETs, not a short in the motor.

 

[Tukkis]

Depends. Is the motor plugged into the controller? And bolted to the frame? Or is it disconnected from everything and separated from the frame?

If the latter, then no, it shouldn't do that; it probably means that either a phase wire thru the axle has been damaged (usually at the axle exit) and is shorting to the axle itself, or a winding is shorting to the stator laminations.

If the problem did not exist before the bearing replacement, then axle wiring is the most likely culprit, as it could be damaged during cover removal or reinstall.


To find out *which* phase it is on, you would need to disconnect the Wye point between the phase windings inside the motor itself. Then each phase is independent and the short would only show up on the actual damaged phase.

To see whether it is a winding or phase wire problem, you would have to disconnect the winding from the phase wire, and test each. The one that's still shorted is where the fault is.



If the former, then it could do that if the battery negative wiring of hte controller is grounded to the frame, and the axle is grounded to the frame, and the test equipment's continuity / diode mode is capable of causing the FETs in the controller to conduct during the test, so that it's really seeing the battery negative conection thru the FETs, not a short in the motor.

Hello! Thank you for your informative reply!

Strator is out of the hub and phase wires are ok. So its the windings. Will this evening check everything with loupes and poke the windings out of the strator body

Phases are not grounded to hub? And couldnt give continous because of that?

-TukkiS

 

[Tukkis]

Found it! Theres a small plastic wrap unfolded from the windings, but it was glued to the strator, it seems like its been there for some years? And i and the previous owner have been driving this motor. Is it possible to drive shorted hub?

-TukkiS

 

[amberwolf]

Strator is out of the hub and phase wires are ok.

That means that you disconnected the phase wires from the windings, and measured phase wires to axle/etc and get no reading, correct?

So its the windings. Will this evening check everything with loupes and poke the windings out of the strator body

You don't want to remove the windings from the stator--this will require completely rewinding the motor.

If there is a short, moving the windings around at all may just make it worse, and you can damage the coating on the winding wire causing shorts between other windings, too.

Phases are not grounded to hub? And couldnt give continous because of that?

I don't know what you mean.

If you are asking if phases are normaly grounded to the hub, then no--there should be no electrical connection of any wire in any part of the system to any part of the mechanical structure of the motor.

Found it! Theres a small plastic wrap unfolded from the windings, but it was glued to the strator, it seems like its been there for some years? And i and the previous owner have been driving this motor. Is it possible to drive shorted hub?

I don't know what the plastic would be, but plastic can't short things; it's an insulator.

A short can only happen between conducting things, which are almost always metal.

If nothing else is shorted to the stator *except* a single phase, then it's not shorted within the controller system, and could operate--it would be radiating a lot of electrical noise via the entire bike frame whenever hte motor is operated, but should still "work".

 

[Tukkis]

That means that you disconnected the phase wires from the windings, and measured phase wires to axle/etc and get no reading, correct?



You don't want to remove the windings from the stator--this will require completely rewinding the motor.

If there is a short, moving the windings around at all may just make it worse, and you can damage the coating on the winding wire causing shorts between other windings, too.





I don't know what you mean.

If you are asking if phases are normaly grounded to the hub, then no--there should be no electrical connection of any wire in any part of the system to any part of the mechanical structure of the motor.




I don't know what the plastic would be, but plastic can't short things; it's an insulator.

A short can only happen between conducting things, which are almost always metal.

If nothing else is shorted to the stator *except* a single phase, then it's not shorted within the controller system, and could operate--it would be radiating a lot of electrical noise via the entire bike frame whenever hte motor is operated, but should still "work".

The insulator wrap had unfold itself little bit, i moved it back to underneath the windings and now it seems to be ok!
Ill spray some insulation coating after it arrives. I think this motor is now fixed

 

[calab]

Interesting read on the various methods

4 Types of Motor Winding Insulation Methods | Dreisilker Electric Motors

Read about the 4 Types of Motor Winding Insulation Methods that Dreisilker offers its customers based on their unique system needs.

dreisilker.com

 

[amberwolf]

The insulator wrap had unfold itself little bit, i moved it back to underneath the windings and now it seems to be ok!
Ill spray some insulation coating after it arrives. I think this motor is now fixed

Ah, ok.

If you do have a winding short, I recommend CoronaDope as it's intended for repairing coil windings. I fixed an MXUS 450x (4? 3?) motor with it, drizzling it down into the suspect areas with the brush it comes with, and inserting ziptie cutoff bits to keep the spacing, and it didn't have another problem with that in the rest of the time I used it. Unfortunately the mechanical construction of the motor wasnt' up to my task, so not all that long afterward I replaced it. Still around here somewhere though.

 

[Tukkis]

Ah, ok.

If you do have a winding short, I recommend CoronaDope as it's intended for repairing coil windings. I fixed an MXUS 450x (4? 3?) motor with it, drizzling it down into the suspect areas with the brush it comes with, and inserting ziptie cutoff bits to keep the spacing, and it didn't have another problem with that in the rest of the time I used it. Unfortunately the mechanical construction of the motor wasnt' up to my task, so not all that long afterward I replaced it. Still around here somewhere though.

Thank you for all the help!
I allready purchased, what we have here in Finland. And well there was two brands crc and some other, so i bought crc it was easiest to get. Hopefully it will hold as good as CoronaDope

TukkiS