hub motor RANDOMLY make weird noise

[marce002]

Hello

I have a 350w front wheel stndard hub motor, and started to RANDOMLY make weird noise and try to turn with no torque but can hear turning.... the problem is that i do not know when will this happen. I tested all hall sensors for 5v and they seem to be ok... what else can it be? I have never taken it apart and it has moderate use and no water roads....i use it with dc motorcontrollerbylithiumbattery (12s 18650 in fact two packs 6s each)

 

[HK12K]

To begin, check all of the phase and hall wiring for damage. Pay close attention to where the wires exit the motor itself as that is a common failure point, though it could be anywhere.

 

[Chalo]

Maybe have a look at the gears? They don't fail that often, but they do sometimes if they get too hot.

 

[marce002]

yes but why do his randomly, the 70% of time is perfect no noise at all.

 

[Chalo]

90% of the time, the problem is a plug or cable. So try to eliminate that cause first.

The last intermittent problem I had with my bike was a battery cable plug that got hot and out of shape internally, without showing any problem on the outside.

 

[dogman dan]

If you hear it turning, but the wheel don't turn, then likely the key is sheared where the gears meet the axle shaft. It could be grabbing occasionally and working normal, then slips again. More usual, it cuts that key and just spins the motor but not the wheel all the time.

But I'd say more like 99% of problems are wiring, plugs, nicked wires, etc.

Random screams for it to be a plug that contacts intermittent, or even a broken wire inside the insulation sheath you can't see. Not sure what you mean by your description. hears it turning makes us think a geared motor.

Or, you just describe classic motor stutter, and or motor that runs on just two phases. I had a motor once that ran perfect no load, but no pull. One phase wire was cut, all but one strand. It could pull easy on one strand, but under load it ran on just two phases, and stuttered.

 

[marce002]

What it does is this

https://youtu.be/_Lr90DRQdVA

Note at the end working fine suddenly

 

[marce002]

Also noted that using the walking 6kmh feature it never fails... maybe low volt works fine and at 50v sometimes fails
.
So no sensors and no wires issue

 

[Chalo]

Also noted that using the walking 6kmh feature it never fails... maybe low volt works fine and at 50v sometimes fails
.
So no sensors and no wires issue

That's a faulty conclusion. If you have a poor phase wire connection, it may not show any symptoms at low load.

 

[marce002]

Dogman dan thanks for your tips... it is not phase cables issue nor hall sensor or wiring almost 100 sure... tested them hundred of times.... maybe has to do with the key you mentioned but did not understand
.. what do you call key?

 

[Voltron]

Assuming you have a gear motor with an internal clutch .. The clutch slides onto the axle, and is kept from spinning with a square metal rod (key, or keystock)
Sometimes the whole clutch is starting to slip internally..

 

[dogman dan]

The clutch is broken I think. Sounds like it grinds a while, then finally grabs. When I broke a key, it just spun and never grabbed, or made grindy noises. The noise doesn't sound like stutter, so I think you are right that its not the wiring.

The easy fix is just get a new motor. The clutch could be welded to make it always grab, but the bike would not freewheel and coast as nice after that. Not sure what you have, but most vendors will only sell you a whole motor, not parts for them. And even the same brand may have changes that make swapping out parts a problem. But it may be possible to buy a bare motor, then just swap the cores out.

 

[marce002]

Thanks to all... now more clear all aspects
.

The motor is this to make clear

 

[Voltron]

That's a gear motor with a clutch alright.
FYI the axle is mounted upside down... The little mouth on the end of the axle is supposed to face down so rain water doesn't drip in it