Problem: Hub motor vibration/buzzing when under load

[TannyFordas]

Hey, brand new to the forum so sorry if I've done anything wrong. Okay, so Im running a voilamart 1500w hub motor and I recently swapped the included controller for one which supports an lcd. Everything works except for the fact that the motor now makes a loud buzzing sound when it starts up under load. This noise was totally absent from the previous controller and is similarly absent when the motor is lifted off the ground or when the bike is already at speed. I cannot identify the brand of the original controller, the replacement controller is a kt 35A controller and the display I'm using is a kt lcd8h. Does anyone know what might be going on?
https://pasteboard.co/J35ZsCD.jpg
Hub motor
https://pasteboard.co/J360IZD.jpg
Original controller
https://pasteboard.co/J361dqg.jpg
New controller
https://pasteboard.co/J362n2h.jpg
Lcd configs

Edit: I feel I should mention that the same behaviour was exhibited by another controller, a brainpower 50A controller. At the time I chalked the issue up to the controller and I remidied the issue by returning to the original controller.
https://pasteboard.co/J3696Xs.jpg
Brainpower controller.

 

[amberwolf]

Okay, so Im running a voilamart 1500w hub motor and I recently swapped the included controller for one which supports an lcd. Everything works except for the fact that the motor now makes a loud buzzing sound when it starts up under load. This noise was totally absent from the previous controller and is similarly absent when the motor is lifted off the ground or when the bike is already at speed.

is the current draw (and heat) of the motor and controller the same as it used to be?

if ti's greater now (possibly less range on the battery, more voltage sag under load), then a wrong phase/hall wiring combination is the most likely issue. (wire colors dont' always just match up the same between systems) does your controller have "self learn" wires?

if it's about the same, then a simple hall signal connection problem is the most likely.

connection problems in general are almost always at fault for problems in systems that have wires or electrical interconnections of one form or another. anything from poor solder at the pcb junction, to broken conductor inside the insulation, to contacts not mating correctly, or oxidized/contaminated, to wires not crimped in them correctly, to wires broken at the crimp itself (but held in place by the insulation), etc.



side note: instead of externally linking, if you attach images directly to the post using the attachments tab, which uploads the image directly to the es server and stores (and serves) it with the post, it allows anyone that can see the post to see the images. (externally linked pics may not be visible to everyone, as this is a worldwide forum and some sites are simply not accessible everywhere, among other potential problems).

 

[TannyFordas]

if ti's greater now (possibly less range on the battery, more voltage sag under load), then a wrong phase/hall wiring combination is the most likely issue. (wire colors dont' always just match up the same between systems) does your controller have "self learn" wires?

if it's about the same, then a simple hall signal connection problem is the most likely.

connection problems in general are almost always at fault for problems in systems that have wires or electrical interconnections of one form or another. anything from poor solder at the pcb junction, to broken conductor inside the insulation, to contacts not mating correctly, or oxidized/contaminated, to wires not crimped in them correctly, to wires broken at the crimp itself (but held in place by the insulation), etc.

Current draw on the new controller is exactly the same as the previous controller, though the addition of the LCD does mean there is the option of adding/removing a "slow start" through the c5 parameter which may have been included by default on the non programmable controller. there are no self learn connectors. the current was definitely greater with the brainpower controller as it would try to pull 50A.

it seems unlikely that there would be a poor connection from the halls given that swapping the old controller in and out is all that's needed to fix the issue?

how would I diagnose a hall/phase mismatch?

Edit: After testing, the C5 slow startup parameter had no impact. starting torque is definitely much lower than it was with the old controller regardless of settings and even at comparatively low current, the noise is still present.

 

[TannyFordas]

okay, so i think this might be my inexperience rearing it's ugly head. is it possible that my original controller was simply a sine wave controller while both of the new controllers are square wave? would it be reasonable to assume that a bog standard ebay 1500w kit would come with a sine wave controller?

 

[goatman]

whats your no load amp draw?

 

[TannyFordas]

whats your no load amp draw?

with the new buzzy controller it's 0.95A, not sure with the old quiet one

 

[goatman]

whats your no load amp draw?

with the new buzzy controller it's 0.95A, not sure with the old quiet one

ive noticed when my motor kind of growls when starting from a stop, so under load. instead of being pretty such silent and butter smooth.

each time ive come across it, its become my early warning signal to replace my motor cable. the hall wires where they pass through the axle get damaged for some reason, actually I know why, but you might want to flip the bike upside down and wiggle the motor cable by the axle while giving some throttle and see if your motor starts making different sounds just to make sure its not your cable

 

[TannyFordas]

whats your no load amp draw?

with the new buzzy controller it's 0.95A, not sure with the old quiet one

ive noticed when my motor kind of growls when starting from a stop, so under load. instead of being pretty such silent and butter smooth.

each time ive come across it, its become my early warning signal to replace my motor cable. the hall wires where they pass through the axle get damaged for some reason, actually I know why, but you might want to flip the bike upside down and wiggle the motor cable by the axle while giving some throttle and see if your motor starts making different sounds just to make sure its not your cable

I find it hard to belive that the issue lies on the motor side as I just replaced the new controller with the old one and the result is the quiet buttery smoothness I'm used to. I've spent a little while looking up comparisons between square wave and sine wave controllers and the sound of the buzzing from the square wave ones mirror my experience with the new controllers.

The final nail in the coffin is that I cracked open my old controller and found this printed on the pcb
https://pasteboard.co/J3e5izrW.jpg
So it seems to me that because my only experience with this motor has been with sine wave controllers, that it was the characteristic buzz and "gravely" feel of a square wave controller which caught me off guard? Does this sound reasonable?

Do square wave controllers normally feel so much rougher than sine wave controllers?

Oh and as an ademndum, I can't seem to figure out the attachment method of adding photos as I can only upload photos less than 500kb? Am I doing something wrong?

 

[goatman]

I use imgur.com for uploading pictures, its free and it takes your picture and resizes it so you can post your pictures here easily. ive never used square wave controllers so I don't know