Hi everyone, i'm new to this Pedelecs site but so far what i'm seeing is really good. My issue is i run a Kirby ebike 52volt 1500/2000watt converted bike. I'm on year 4 of this brilliant bike i built for leisure. During a ride out i experienced a loss of power so after a struggle home and investigation I realized my 40amp fuse had blown inside the battery case. Changed it it blew immediately, i was lucky enough to have a spare (from Kirby ebikes) controller which is a KT36/48zwsrcld 17amp . After connecting it up and pressing the throttle i now get "Motor position sensor fault" the wheel spins momentarily and then needs a power down and back on to do the same again. Any advice please..
Motor position sensor fault
- Thread starter landroverlandyman
- Start date
If the fuse is blowing, you probably have a blown MOSFET in your controller. Actually, I'm surprised that 17A KT controller would last that long with a 1500w high speed motor because it would be drawing maximum power most of the time on level 5.
It would be indicated by the motor kicking or jerking. Is it kicking or turning under power before it cuts?
Either way, you can test by measuring the resistance between each battery wire and each motor phase wire. In each group of three, the resistances should be the same and in the range 5k to 20k.
It would be indicated by the motor kicking or jerking. Is it kicking or turning under power before it cuts?
Either way, you can test by measuring the resistance between each battery wire and each motor phase wire. In each group of three, the resistances should be the same and in the range 5k to 20k.
Thanks for replying so quickly. I agree with you the 17amp controller seems to small hence why i have had 3 of them including this spare one. Can i just say the fuse is NOT blowing now the new controller is fitted.
I cannot fault the kit it's fantastic and i use the bike regularly with no issues.
The tests you have suggested is what i will try now. Thanks
Would you know if i can simply unplug the hall sensor plug ? Or do i need a sensor less controller for that. ?
I cannot fault the kit it's fantastic and i use the bike regularly with no issues.
The tests you have suggested is what i will try now. Thanks
Would you know if i can simply unplug the hall sensor plug ? Or do i need a sensor less controller for that. ?
I have many happy memories of Stoke-on-Trent. My favourite Aunt, Uncle and Grandparents lived in Chell.
If the controller is not working now, you need to test it. With that motor you need at least a 9 FET controller (22A). A 12 FET would be better, but they're quite big. Limit the current to whatever the battery can give, then mainly use the lower pedal assist levels.
Just slightly above my level of knowledge I’m afraid, it will work but when the error message “motor position sensor fault “ appears it knocks the motor off . The only way to get the motor running again is to power down and back on. A shop in Birmingham ( my perfect e-bike) has offered me a sensor less controller he seems to think that will be ok even if one of the sensors has failed. The one he’s offering still shows the plug for the hall sensors on which is confusing me .
Before anything, make sure that the motor cable connector at the motor end is in all the way to the marked line. I will not help you further until you confirm that the edge of the connector reaches that line.
After that, check any connectors at the controller end, then check whether the motor cable has been damaged where it comes out of the axle.
Mine is hardwired straight into the rear hub and at the controller end the hall sensor cables are on a plug and socket and the phase wires are connected on eyelets in a 3 way joint box.
Since we poke earlier i have removed the rear wheel, and taken the motor out, there's nothing obvious wrong . I have checked all the cables for continuity and all seem fine.
Since we poke earlier i have removed the rear wheel, and taken the motor out, there's nothing obvious wrong . I have checked all the cables for continuity and all seem fine.
You can check the hall sensors without opening the motor. Set your meter to 20v D/C scale if it has one, put the black probe on the black hall wire and the red probe on each of the blue, green and yellow wires. Turn the motor slowly. You should see around 5v switching on and off as the wheel turns.. You must do that with the controller connected and switched on.
If that twst is OK, you can do the phase wire check. keep the meter on 20v A/C this time. Select any pair of phase wires to test. Turn the motor as fast as you can with your hand. You should see it generate some voltage. repeat for each pair.
If that's OK, you should've done the MOSFET test I mentioned earlier.