HUB MOTOR CAPABILITY

[Deleted member 4366]

You just need to lift the wheel off the ground and spin it up to maximum. Make a note of the voltage and the speed, then you can calculate the kV, so anybody can calculate what speed they'll get with a full or empty battery. On-the-road speeds with somebody pedalling aren't particularly meaningful.

 

[Woosh]

I didn't have much time.
The container arrived a couple of days before I flew out.

 

[mountainwheelchair]

Hi all,

I came across this post because I think I just burnt out my motors

A moment ago I hooked up my Mac 536hf motor to a Kelly KBS48101X controller for the first time. Both were brand new and had never been used before.

Initally I was over the moon to see that the motor start spinning, however...

The motor seemed fine when spinning in one direction, but struggled to spin in the opposite direction.

Part way through this video, a warning light comes on the controller, and then although you don't see it, smoke starts to come out of the motor! Eek!

As I was recording, I quickly disconnected the battery and tried to film the smoke but the camera didn't pick it up. The motor housing was really hot to the touch, and the cables were quite warm too.

Looking in the controller manual, the flashing red LED translates to error "Motor did not start - Motor did not reach 25 electrical rpm within 2 seconds start-up. Hall sensor or phase wiring problem".

However, I've checked the wiring diagrams for both the controller and the motor and it seems to be correct.

As the motor housing was so hot, I decided to open it up thinking it would coo down quicker and do less damage. Much to my dismay though, it looks like the windings have burnt out:

Click for Full Size Version

It's a geared hub motor with a 20T winding. Clearly it wasn't turning properly but I'm really surprised to burnt out just in the time it took me to make that video.

Does this mean that my motor is trashed, and how do I prevent this from happening again?

 

[anotherkiwi]

Sorry, I'll stop laughing I promise!

 

[mountainwheelchair]

Sorry, I'll stop laughing I promise!

I don't mind people laughing at my expense, honestly I don't. In fact I quite appreciate it. However, if you're able to see the humour in my error it suggests that you understand my error, in which case it would be useful if you shared... Please

 

[Deleted member 4366]

Geared motors normally only go in one direction because they have a clutch. The hall sensors are then sometimes set asymmetric so that the motor is optimised for torque in the one direction. That means that the timing is incorrect in the opposite direction. I can only guess that that was the problem you had, but the main thing is you broke the golden rule: You must never give throttle to a motor that isn't running correctly. The controller will still attempt to give power, and the power has to go somewhere other than to turn the motor.

Your picture doesn't show, but if the windings aren't too badly burnt, you might get away with only needing to replace the hall sensors.

Did your motor have a clutch? Did you weld it?

 

[mountainwheelchair]

Thanks for the reply d8veh. No, I've not had to weld the clutch. The manufacturer (Mac) installed what is essentially a woodruff key on the shaft so it would operate in both forwards and reverse directions (it's for a wheelchair). In which case, one would presume that the manufacturers also installed the hall sensors appropriately?

The Kelly KBS48101x controller which I'm using has programmable firmware. Part of that is a function which limits the current/voltage/speed when operating in a reverse direction. I thought it was the controller not supplying enough power until I watched the video back and worked out what the error message was.

 

[mountainwheelchair]

Woohoo!!! It's working perfectly; the phase/hall combination was wrong.

Although it's now much slower, speed in both directions looks the same to the naked eye.

I ran the motors in both directions for 60 seconds whilst applying as much resistance as I was able to with my hand and the motor showed no signs of overheating. I'm very impressed with the torque; even if apply as much pressure as I am physically able to with both hands I'm still not able to prevent it turning even at a very low speed. And this was with the "burnt" motor too.

Here's the photo of the "burnt" coils again (it won't let me edit my previous post).

Seeing as the motor is working, should I be concerned about the burnt coils?

 

[anotherkiwi]

The insulation looks pretty far gone in a couple of spots, the pros will give their opinion.

My earlier bout of laughing was me visualising the scene, sorry bout that! Reminded me of a couple of moments I have had myself.

 

[Deleted member 4366]

Unfortunately, you can't unburn them, so you can only comtinue with it in the hope that the coils don't short. There's no way to say if it'll ne OK. Only time will tell. I'd take a chance on it, but if it does ever give any problems, do not give it anything more than minimal throttle, otherwise you run the risk of blowing the mosfets in your controller.

 

[mountainwheelchair]

Thanks guys.

I'm using the motor to create a six-wheel-drive wheelchair which will carry my daughter into the mountains. More info here: http://mountainwheelchair.com

Seeing as there'll be six other paired controllers and motors on board, and it will be my daughter driving the wheelchair, I'm not sure I'd notice if quickly enough if one wheel lost drive.

I think I'll just go ahead and order a replacement motor. Ultimately, I don't want my daughter stuck up a mountain because I decided to risk using a semi-burnt motor.

 

[soundwave]

http://www.quadrix-team.com/en/product/quadrix-watts-2/