Hub motor not working

Tommy_p

1 µW
Joined
Apr 7, 2021
Messages
2
After few weeks of testing my 1500w 52v ebike I got hungry for more power so I made a shunt mod and unfortunately ended up with dead motor. My first guess was the controller as I've heard a noise similar to capacitor explosion after 15km of riding in a city.
Well, it works but only if I spin it a bit and then makes a lot of noise(not sure if it's motor or controller) especially when I'm trying to ride a bit faster than the speed of walking. Beside that the wheel gives a lot of resistance while trying to spin.
Here's a picture of opened motor.




Any chance of reviving?


PS. Sorry for my English.
 
resistance when hub is unpowered means the phase wires are touching

and you heated that motor up and dagamed it

time for you to buy a new motor
 
After little inspection it turns out that two phases are shorted. Is it worth of my time to search for it and try to remove or is it most definitely so dense that the only way is to rewind the motor and if so is it very difficult to do that? Anyone tried it before? Maybe there are some guides on the forum?
 
You don't need to go looking for it... It's right there at the bottom of the picture. Those burnt winding are the culprit. New motor time :cry:
 
Whatever you do don't buy another from the same manufacturer. That's the worst winding job I've ever seen on a hubbie. Not only are the turns around the teeth not neet, tight and uniform, but the long spans of magnet wire just doesn't appear right and is sure to result in failure. Wires in a motor winding experience forces as pulses of current in alternating directions occurs. That can make motors "sing" somewhat. Without them being glued and tied down the vibrations wear through the varnish on the copper wire and create a shorts...especially on those long spans with the magnet wire touching the metal of the stator hub.
 
Aren't motors dipped in something to help reduce vibrations?
Winding wires are packed down on each wind, helped to be isolated between teeth with the motor winding paper.
Theres a lot that goes into making the hub motor
Theres a lot more that goes into making a hub motor last longer.
Magnet strength
Magnet quality
Magnet glue
Magnet gap
Lamination thickness
Lamination metal quality
Lamination metal grain direction
Total lamination numbers
How deep the slots are, how wide
Theres a lot more

Probably theres is a difference in the quality of winding wire, like how much insulation coating is on the winding wire itself. And how does that coating affect the motor itself, eddie losses, core losses etc. Couldnt you just keep coating that magnet winding wire and get the thickness of coating you wanted. Then theres the quality of the liquid coating itself.

What I often wonder about is how do they calculate and measure for optimal winding fill. That would be an interesting video to find on youtube.



John in CR said:
Whatever you do don't buy another from the same manufacturer. That's the worst winding job I've ever seen on a hubbie. Not only are the turns around the teeth not neet, tight and uniform, but the long spans of magnet wire just doesn't appear right and is sure to result in failure. Wires in a motor winding experience forces as pulses of current in alternating directions occurs. That can make motors "sing" somewhat. Without them being glued and tied down the vibrations wear through the varnish on the copper wire and create a shorts...especially on those long spans with the magnet wire touching the metal of the stator hub.
 
markz said:
Probably theres is a difference in the quality of winding wire, like how much insulation coating is on the winding wire itself. And how does that coating affect the motor itself, eddie losses, core losses etc. Couldnt you just keep coating that magnet winding wire and get the thickness of coating you wanted. Then theres the quality of the liquid coating itself.

What I often wonder about is how do they calculate and measure for optimal winding fill. That would be an interesting video to find on youtube.

Regarding the winding wire, the primary difference between different qualities is the temperature rating of the "varnish" on the wire. That typically is the ultimate temp limit of a well built motor, though the temperature rating of the magnets can often come into play. The manufacturers also use different alloys of copper that affect the stiffness of the wire, which affects how easy the stator is to wind.

How do you optimize?...Whatever is the most copper that will fit. If I was to try winding a motor, then I'd get some reasonably flexible magnet wire and see how many turns with one strand I can fit wrapped neatly and uniformly around adjacent teeth. That total number of strands around each tooth would be the "optimum", which would be unlikely to be possible with multiple strands on each turn.

Then after getting the winding done neat, tight, and full, it is time to avoid problems with loose strands especially over the long distances. I'd use a good high temp string (cotton maybe?) to tie things together, and use thin strips of wood or thick paper to insulate the wire from metal. Then I'd use high temp epoxy to glue things in place to ensure looser wires a prevented from vibrating, but taking some care not to use so much epoxy that it insulates the magnet wire.
 
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