Hub motor high no load resistance

[jordanjozsef]

I've got an electric scooter hub motor (48V 1500W), which is new for me, because I have 3 hub motors and I've seen much more motors, but the usual scheme is when I spin the wheel with my hand it's easy and it gives a whinning noise which will go away as the wheel slows down. But this beast motor just doesn't do the whinning noise, it's humming in a lower frequency and I can feel that it's "clicking" (don't know how can I say that, I can feel that the magnet is pulling and pushing the stator). It much harder to spin anyway. I tested it by shorting the phase wires together, because my first thought was that the phase wires were shorted, but no, when I shorted the wires the resistance was much more and it was't "clicking" that much. Can this motor be a well made product? It has almost no noise when load applied, the stator is skewed and 65 mm wide which is the widest stator I've ever seen. Of course the diameter is small, because it's a 10" motorbike wheel. I think the strong magnetic force and the small gap between the magnets and the stator gives this resistance or am I wrong? The pictures were taken before the renovation it's a 14 years old motor. It's not clean, Statorade added and it's ready to ride. I haven't tried it with much power, but I already felt that this is gonna be a powerful motor. It's a high speed motor (~50 km/h @ 48V) , but still had torque.

 

[amberwolf]

it could still have a phase shorted to the stator, or even multiple partial shorts to the stator between phases.

sometimes these are not evident with a regular multimeter, even if you disconnect the star connection between phases inside the motor, and require a high-voltage "isolation" tester.

it could also be that the motor has bearing issues, or something else rubbing inside. there is a tiny spot on the glue along the outer edge of one fo the windings that looks like it might have been rubbing on the cover inside.

or it could just be designed in a way that it doesn't spin well unpowered. if it has a very low noload current draw when operating off ground, at all throttle levels, then it's probably not failed or failing, and just has a poor design for unpowered spinning.

 

[jordanjozsef]

I'll check the current draw at different speeds and then I compare my other hub motor to see if it's a phase short or it's because of the design. The bearings are new too, but it was the same with the old bearings.

 

[fechter]

The skewed stator will reduce the cogging (clicking as you put it). The real test will be to run it and measure the current.

 

[jordanjozsef]

5A at full throttle from 60V, which I thought is much, but my other motor draws 3-4 amps from 36V, so it's not much higher. As you can hear the video, it resonates much at low rpm, so the scooter won't be suitable for low speed riding.
https://youtu.be/WtBzjTKIiNY

I don't have a battery yet, but the cells are on the way (280 total, 104V 31Ah)

 

[dogman dan]

Big magnets on that thing, it would just naturally cog a lot more than other smaller motors. Doesn't sound shorted though, since it gets a lot worse when you do that.

 

[jordanjozsef]

It sounds quiet when it gets up to speed, I think it's the thick magnets that makes it more noisy at low RPM. At higher RPMs it's so quiet. I'll see how it will perform under load, but I think it will have lot of torque.

 

[fechter]

5A at 60v for a motor that size is about right. I think the motor is fine.