Greared motor noise

[chrashing]

Does this sound like an obvious motor problem? Any idea's on what this noise is? I know gear motors makes some noise, but I think this noise louder than should be expected.

I have about 100 miles on my:Model: 2013 Conhismotor Brushless Gearless Mini Hub Motor 48V 350W. It runs great, but.... During acceleration, it often makes a louder growling sound from the geared side of the hub. Originally only happen with hard throttle, but is beginning to happen more often, with any throttle. It's not a gear grinding tooth splintering noise, sounds like a bearing issue inside the hub.

If I peddle for a stroke or two as I initially accelerate, I seem to be able keep the noise from occurring.

The noise kinda kills my motor stealthiness which I don't like, but otherwise does not sound like something is being immediately damaged.

I am clueless about the working of these hubs, imagine the freewheel clutch is loose, and is missing a critical spacer/thrust bearing to keep is from rattling or something. I have never opened a hub.

Thank you for any ideas.

 

[d8veh]

It's impossible to say without hearing it. The controller fires pulses of power at the motor. These make a bit of noise at low speed. The wider your throttle, the bigger the pulses, so the louder the noise. In effect, your motor can act as a sort of loudspeaker.The noise is a little bit like a growl as you accelerate from a standstill, or use high power slowly up a hill. At higher speed, you don't get so much current in the pulses, so it'll be quieter. Noise at speed is bad news. Noise at low speed can be normal, but the higher current at low speed will also make any abnormal noise louder. Can you do a Youtube video?

 

[chrashing]

Hello d8veh, Thank you for the great explanation of the sound due to the controller pulses. Maybe the reason I'm hearing it more lately is the 'Need for Speed' I've developed with this go-kart/trike. I will listen to the sound with a new ear next ride.

I'll attempt to capture the sound.

Thank you.

 

[lbz5mc12]

Have you checked all your connections to make sure nothing has jiggled loose? One of my hub motors made a similar noise and it turned out that one of the wires wasn't connected all the way.

 

[chrashing]

Have you checked all your connections to make sure nothing has jiggled loose? One of my hub motors made a similar noise and it turned out that one of the wires wasn't connected all the way.

I'll check those. Thank you!

 

[wesnewell]

If the noise goes away while pedaling then it's likely just a dry freewheel. They can get real noisy when dry. Dump some 90w gear oil in it.

 

[chrashing]

Finally got to the bottom of my noise issue. Turns out the noise is the growl of the motor under load, but in my case enhanced due to the metal flag holder. The flag holder was tightly bolted to the axle and rested against the rear aluminum bike rack. Somehow this combination increased the growling sound, so much a kid the other day, asked if the noise was a horn.

Got lucky today when I noticed the steel flag holder was wearing a grove into the aluminum bar of the rack. The noise quieted when I squeezed a business card between the holder and the rack.