Possible issue with new Mac motor

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Fuzzy Head   1 mW

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Possible issue with new Mac motor

Post by Fuzzy Head » Sep 24 2014 2:01pm

Hello all,

I recently bought myself a Mac motor kit from em3ev of which appeared to function perfectly when I did a short powered test of the motor and controllers. At the weekend I finally got a chance to start installing it properly and while modifying my torque arm I realised that the wheel would not spin properly. At this point it was resting in the slots on the front fork (upside down) in the air (not sure on technical terms) and there were no obstructions preventing it spinning. I opened the hub and took out the motor and could see no obvious problems. At this point I have not even removed the protective wrapping on the wheel rim so I know I haven't damaged anything.

I suspect a problem with the clutch but am not certain. When I spin the wheel so it spins as if coasting forwards it spins fine with almost no resistance. But a few times when I have tried to spin the wheel backwards it has jammed. Most of the times I have tried spinning it backwards it has a good amount of resistance. I think it may be normal to feel a strongish resistance force when turning the wheel backwards due to the motor being spun but can someone please confirm this is normal?

I would really appreciate it if anybody could offer some advice as to what they think the problem could be or what may be worth doing?

Is it safe to try adding some oil to the clutch?

Thanks

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teklektik   10 GW

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Re: Possible issue with new Mac motor

Post by teklektik » Sep 24 2014 2:13pm

Fuzzy Head wrote:When I spin the wheel so it spins as if coasting forwards it spins fine with almost no resistance. But a few times when I have tried to spin the wheel backwards it has jammed. Most of the times I have tried spinning it backwards it has a good amount of resistance. I think it may be normal to feel a strongish resistance force when turning the wheel backwards due to the motor being spun but can someone please confirm this is normal?
Resistance is normal - 'jamming' is not. There is no clutch issue, but the gears seem obstructed.

Check to see if you have introduced a bit of mungus into the gears. Rotating backwards the clutch engages and the gears should turn - yours don't so the clutch is working but the gears aren't.
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Russell   10 MW

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Re: Possible issue with new Mac motor

Post by Russell » Sep 24 2014 6:55pm

Make sure the phase wires are not shorted.

-R
Jeep Comanche Trekking Bike w/YOUE geared motor, 42 lbs + 15 lb rear trunk bag w/12S 16Ah LiPo battery, tools, etc., 21A controller, 700 x 40C tires. 27 MPH.


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dogman dan   100 GW

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Re: Possible issue with new Mac motor

Post by dogman dan » Sep 25 2014 7:06am

Bet that is what is going on. normal resistance when turned backwards. But if two phase wires touch, it cogs like hell.

It could be a shorted controller, but very unlikely.

If it is actually gears jamming, something got in there, or something broke already. Nothing rattles when you shake it?

Fuzzy Head   1 mW

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Re: Possible issue with new Mac motor

Post by Fuzzy Head » Sep 25 2014 12:07pm

Thanks for the replies.

It turned out the resistance was because I wrapped the phase and hall wired up to protect them from damage and all the phase wires were touching each other. Once they were no longer in contact it was able to spin easily.

There is no rattling inside the motor.

I should have time at the weekend to take the hub apart and give it a thorough inspection to see what caused it to jam.

Also, I looked up mungus and it came up with mould :s . Does it mean a bit of muck or debris in this case?

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teklektik   10 GW

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Re: Possible issue with new Mac motor

Post by teklektik » Sep 25 2014 12:31pm

Ya - You mentioned you had opened the case and although it seemed unlikely, there was a possibility that a bit of packing material, etc got introduced.

Again - shorted phases or not, the wheel should turn albeit with resistance. I took 'jammed' to mean it wouldn't turn at all. This may have been a bad interpretation of the term on my part.

BTW - This resistance effect is actually of diagnostic value, not just an interesting effect when messing with the wires. If you ever suspect controller issues, turn the wheel backwards with the controller connected and power off. The same kind of heavy resistance you felt with shorted phase wires is an indication of a failed and shorted FET.
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Fuzzy Head   1 mW

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Location: England

Re: Possible issue with new Mac motor

Post by Fuzzy Head » Sep 25 2014 1:03pm

Thanks for your reply

The motor did jam a couple of times, as in it could not move at all, but then seemed to come free. The motor requiring a lot of force to turn was an observation and I do not believe the shorted phase wires were related to the jam.

Thanks for the advice that will be very useful if I ever run into a problem with the controller.

I probably could have avoided this if I had more carefully checked for bits of packaging stuck to the mechanics. The outer bit of the hub connected to the rim by spokes was in a separate package to the motor, gears and side plates so plenty of opportunity for bits to get in the gears before assembly was complete.

melodious   100 kW

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Re: Possible issue with new Mac motor

Post by melodious » Sep 25 2014 1:58pm

Since you have the motor open, you may as well spray some anti corrosion spray on the windings and such. Keeps the rusting to a minimum.

http://boeshield.com

I also open my controller and spray the circuit board as well. 8)

Edit: and my throttle too. :lol:

Edit edit: and my bicycle chain :mrgreen:
Surly Ogre rigid 29er, rear 10T MAC @ 50V 25AH & 40A: 30mph road/gravel/hill machine
42" dual diagonal Eskateboard @6s & 90mm wheels
Next: eMTB @10-12s & 8"-12" pneumatic wheels; Got Strapped? d-(',')z

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