Hub motor noise

White_Ferret

10 mW
Joined
Oct 7, 2016
Messages
23
Hello,
I have 24" bicycle with 36v 250w rear hub motor, 350w controller and 36v battery and I have a problem with the motor.
When I push the throttle little bit and the I push it for full throttle the motor make terrible noise but if I push full throttle it runs smoothly without any problem.
I checked the motor gear and it is in very good condition
Do you know why it happens ? It always was like that since I built the bicycle.
Thank you
 
It's most likely a timing problem from the controller. Is it a sensorless motor or are you runing it sensorless?
 
d8veh said:
It's most likely a timing problem from the controller. Is it a sensorless motor or are you runing it sensorless?
It is sensored motor with cheap (12$) sensored controller

Sent from my ONE A2003 using Tapatalk
 
I have another question
Why there is freewheel thread on both sides of the motor ? (see photos)



 
Cheapest thing to try first, would be a different throttle.

I don't know why, but I used to have a throttle that worked fine with one controller, but not any others. I'm suggesting the throttle signal might not be right at all throttle positions, like the hall sensor is not right or something.

Works full on, but not so great modulating less. Anyway, a different throttle is a cheap thing to try.

The other thing is the thing it always is, a bad connection somewhere in the wiring. 90% of all e bike problems are just that simple, one connector works poorly. Again, this could be the throttle plug real easy. If you have the square white connectors, they are notorious for one contact backing out of the housing. So the first check is to see that all the wires stay clicked into the plug. Check every single plug on the bike, very closely.

The left side threads can allow using a screw on disc brake adapter. Your motor is a bit old, newer motors just have 6 hole disc mount built in.
 
It could be something in the clutch in the motor (it looks like a gear motor with internal clutch) that it part way engages at light throttle but then slips at high power. When you give it full power right away, it might be locking in better and not slipping. Just a guess...
 
I would guess a bad hall signal. Carefully inspect the connectors from the motor to controller. Could also be the wire colors need to be swapped around to make it work right.
 
Since all connectors look good to you, its obviously a connector problem. :roll:

Seriously, if its not a bad connection on throttle wires, its somewhere else, like a nick in a wire leaving the axle of the motor. It could even be inside the motor, but I'm not joking when I say its always the wire, or the plug.

The controller goes, it stinks and does not run at all. The motor goes, like a hall fails, and it might run if you have it turning when you apply throttle, but it will then run real slow and weak. Yours sounds different, like intermittent runs and does not. That's screaming wires and plugs.

If it IS in the controller, it will be a wire that is soldered to the board poorly. Again, a poor connection. This is rare though.

So if you can't find it, you might open the controller up, which is a bit of a pain because you have to undo all the screws that secure the mossfets, to get the board out to inspect.

It could be the controller does not match the motor, needing the motor wires in a different order. Was this a kit that was supposed to run as it came? or is it a mix and match, diy deal?
 
$12 controller might be the reason. Try a decent one. The sine wave ones with LCDs give you a much better control system.

The thread on the left side is for a band brake if you wanted to use one.
 
It is mix of parts and not a kit
I really think it is clutch problem but I dont know how to check it.
Switching the motor cables is also an option
I remember that I saw a photo (I think in this forum) that explain it but I dont find it


Update:
I found the photo - https://endless-sphere.com/w/index.php/Determining_the_Wiring_for_a_Brushless_Motor
 
I doubt that it's the clutch. They tend to work or not work. What you've described is typical of what you get when you have a bad connection between the motor and controller or a synchronisation issue that you get when the controller doesn't match the motor properly.
 
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