• Howdy! we're looking for donations to finish custom knowledgebase software for this forum. Please see our Funding drive thread

Clacking motor!

unclejam

unclejam

10 W
Joined
Jan 30, 2014
Messages
73
Location
Devon, England
Hi folks
After many months of building, failing and overcoming problems, my bike has finally hit the street.
For about 100metres.....
The hub motor, which spins freely and perfectly when pedalled, turns evil when under power and is emitting a terrible "clack" noise every few rotations ( but seemingly not EVERY rotation). This noise is bad enough to be felt clearly through the bike frame and handlebars and is apparently mechanical rather than electrical but being a noob, I'm not certain.

Can anyone please give me some clues as to what might be happening here, as I'm pretty despondent tonight :cry:
Thanks in advance for any help

Motor - unknown Chinese Crystalyte style, rewired for about 3 KW (was used)
Controller - Lyen 18fet 4110
Battery - 19s 6p 18650
 
BTW motor is direct, non- geared before you ask!
 
Could be a short in the phases. Do you have a motor tester or multimeter?
 
Hi, thanks for the reply - yes I have a multimeter (AND a Cycle Analyst!)
Any suggestions welcome!
 
Hi folks
After many months of building, failing and overcoming problems, my bike has finally hit the street.
For about 100metres.....
The hub motor, which spins freely and perfectly when pedalled, turns evil when under power and is emitting a terrible "clack" noise every few rotations ( but not EVERY rotation). This noise is bad enough to be felt clearly through the bike frame and handlebars and feels mechanical but is obviously being caused by an off/on power phenomenon. When the throttle is eased off to a gentle cruise, the noise stops.

It has been suggested that the magnets may be damaged or chipped, causing a misread by the hall sensors?

Thanks in advance for any help

Motor - unknown Chinese Crystalyte / MXUS style, direct, non- geared & rewired for about 4 KW (was bought used)
Controller - Lyen 18fet 4110
Battery - 19s 6p 18650
 
unclejam said:
Hi, thanks for the reply - yes I have a multimeter (AND a Cycle Analyst!)
Any suggestions welcome!
Click to expand...

Test for any shorts between the phases and also between the phases and the axle. Make sure to hand spin your motor while testing to see if that makes a difference.
 
unclejam said:
Hi, thanks for the reply - yes I have a multimeter (AND a Cycle Analyst!)
Any suggestions welcome!
Click to expand...

Test for any shorts between the phases and also between the phases and the axle. Make sure to hand spin your motor while testing to see if that makes a difference.
 
Thanks very much for the advice, I'll give that a try.
Its raining today so at least I dont feel that "im not riding" stress
:D
 
Hi, no it was doing it immediately I pulled away for the first time, although the motor was still pulling pretty strongly. Someone else has suggested that it sounds like a chipped magnet interfering with the halls? When I backed off the throttle to a cruise / coasting speed, the effect lessened almost to a stop.
The feeling is as if the power is being switched on and off very rapidly and it is not synchronised with the rotation of the rear wheel, happening more randomly. Another weird aspect is that the Cycle Analyst is showing a small regeneration percentage, (about 6.5%) although I have not used this feature.
 
I found this page online which is really useful - helpful explanations too for Noobs like me.

https://zenid10.wordpress.com/category/4-how-to-guide/4-9-hub-motor-diagnosis-and-repair/
 
I have solved the mystery of the clacky motor and its not wiring related. On lifting the bike off the floor and checking for problems under power, I witnessed one of the rear axle nuts "twitch", accompanied by the strange clack noise. :shock:
It seems that the single (albeit chunky) Hardox laser cut torque arm i have is not enough and the other end of the axle is twitching in the dropout, despite being torqued up tight.

I've ordered a second TA to fit tomorrow and am actually quite happy it's such an easily sorted issue. Thanks to all who offered advice and I'll post a quick vid soon of the maiden ride!
Cheers
 
I spoke too soon :oops:
Axle now has two torque arms and is completely solid but motor still has problems: After a 10 minute ride yesterday, its clear that the "clack" sound is synchronised with the rotation of the motor - it happens every revolution at the same point. Also there is a point on feathered throttle where the noise stops but towards the end of the ride, it started happening with throttle off and coasting downhill too.
I have now tested the phase wires by connecting them together in turn and spinning the wheel by hand to check for shorts - they seem fine.
That seems to leave the halls - could one be broken perhaps?
 
Use the Hall testing guide:

http://www.ebikes.ca/learn/troubleshooting.html
 
Thanks - doing it now
 
Halls sensors check out ok.
Only thing left is to strip the motor :(
 
i had this problem with a chipped magnet. i switched the magnet the other way and switched with a neighbor so that the chip wont be on the hall sensor side. you may also have a n internittant phase short, cover rub on windings?
 
Hi, thanks for the suggestions - I suspect a chipped magnet, as I have tested the phase wires and they seem fine.
I have removed the motor and it will now be going back to the supplier!
 
unclejam said:
Hi, thanks for the suggestions - I suspect a chipped magnet, as I have tested the phase wires and they seem fine.
I have removed the motor and it will now be going back to the supplier!
Click to expand...
If there is no warranty seal on the motor you have never opened it. :wink:
 
You must log in or register to reply here.

Similar threads

J
A comprehensive destruction of the fool cell argument
Replies
21
Views
3,367
spinningmagnets
spinningmagnets
Back
Top