motor problem

gazza19

Pedelecer
Aug 22, 2020
155
3
Hi vfr400 can you tell me how to do the test with a meter please I do have a digital multimeter and really like to know if it is the motor or controller that is at fault it would be much appreciated
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,918
Basildon
Disconnect the motor controller from the battery and thee motor. Set the meter to 200k resistance scale and measure between each of the thick green, blue and yellow and the battery red, then repeat the three readings to the battery black. each group of thre should be the same as each other and normally in the range 7k to 14k.

On the motor side, set the meter to the lowest resistance scale (normally 200 Ohms) and measure between each pair of the thick motor wires. The reading should be in the order of 1/10s of Ohms if your meter goes that low. What you're looking for is a dead short, so after setting the meter and before testing, touch the probes together to see what your meter shows for a dead short.
 
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gazza19

Pedelecer
Aug 22, 2020
155
3
Disconnect the motor controller from the battery and thee motor. Set the meter to 200k resistance scale and measure between each of the thick green, blue and yellow and the battery red, then repeat the three readings to the battery black. each group of thre should be the same as each other and normally in the range 7k to 14k.

On the motor side, set the meter to the lowest resistance scale (normally 200 Ohms) and measure between each pair of the thick motor wires. The reading should be in the order of 1/10s of Ohms if your meter goes that low. What you're looking for is a dead short, so after setting the meter and before testing, touch the probes together to see what your meter shows for a dead short.
Thank you will try that and report the findings on here when I have done it
 

gazza19

Pedelecer
Aug 22, 2020
155
3
Disconnect the motor controller from the battery and thee motor. Set the meter to 200k resistance scale and measure between each of the thick green, blue and yellow and the battery red, then repeat the three readings to the battery black. each group of thre should be the same as each other and normally in the range 7k to 14k.

On the motor side, set the meter to the lowest resistance scale (normally 200 Ohms) and measure between each pair of the thick motor wires. The reading should be in the order of 1/10s of Ohms if your meter goes that low. What you're looking for is a dead short, so after setting the meter and before testing, touch the probes together to see what your meter shows for a dead short.
Is there a video to show the measuring of the pairs of thick motor wires or would you be able to make one showing how to do it to see if there is a dead short on the motor as I just can’t grasp how to do that bit
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,918
Basildon
You pull the three bullet conectors apart to disconnect the motor, then put your probes on the yellow and blue, then yellow and green, then blue and green.
 
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gazza19

Pedelecer
Aug 22, 2020
155
3
You pull the three bullet conectors apart to disconnect the motor, then put your probes on the yellow and blue, then yellow and green, then blue and green.
ah right i get you now thank you so much for all the help you give me i will post the results on here when i do the test on my day off from work do i disconnect the hall sensor connector too
 

gazza19

Pedelecer
Aug 22, 2020
155
3
ah right i get you now thank you so much for all the help you give me i will post the results on here when i do the test on my day off from work do i disconnect the hall sensor connector too
hi i will hopefully be doing the test tomorrow to test for the dead short do i disconnect the hall sensor from the controller as well as the phase wires thanks in advance for the answer
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,918
Basildon
hi i will hopefully be doing the test tomorrow to test for the dead short do i disconnect the hall sensor from the controller as well as the phase wires thanks in advance for the answer
It makes no difference. The halls are on a completely separate circuit.
 
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gazza19

Pedelecer
Aug 22, 2020
155
3
Thank you for all the help you give me and many more people
hi i tried to do the test and put it on 200k ohms like you said vfr400 but it kept jumping between 1 and whatever it was trying to do so could tell what all the measurements were supposed to be when i put the probes on have you any idea why or is it that my metre was being a bit dicky lol
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
14,142
5,474
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West Sx RH
You should be able to get three good ohm readings in the 7-14k zone on the GND/Black wire test, it is only the V+/Red with no power that the reading may be 1 and rising. If you get a zero then a fet has gone.
 
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gazza19

Pedelecer
Aug 22, 2020
155
3
You should be able to get three good ohm readings in the 7-14k zone on the GND/Black wire test, it is only the V+/Red with no power that the reading may be 1 and rising. If you get a zero then a fet has gone.
i did get a reading on the black wire and the red ones stayed the same at 1 so sounds like that is ok as soon as i connect the 9pin motor connector to the the nine pin female connector extension cable that goes to the controller thats when it blows the power so sounds as if its the motor to me but obviously im not too sure trying to find a cheap wheel to try it the motor is a 8fun bafang motor 36v 250w or just another 20inch wheel
 

gazza19

Pedelecer
Aug 22, 2020
155
3
i did get a reading on the black wire and the red ones stayed the same at 1 so sounds like that is ok as soon as i connect the 9pin motor connector to the the nine pin female connector extension cable that goes to the controller thats when it blows the power so sounds as if its the motor to me but obviously im not too sure trying to find a cheap wheel to try it the motor is a 8fun bafang motor 36v 250w or just another 20inch wheel
hi any one able to answer this quickly will be a fantastic help ive just done a phase test on the controller and this is what i got b-b 8.9k ohms b-y 4.1ohms b-g 9.88k ohms onthe red side it was r-b 10ohms r-y 8.9k ohms and r-g 18.8k ohms
 

gazza19

Pedelecer
Aug 22, 2020
155
3
P
hi any one able to answer this quickly will be a fantastic help ive just done a phase test on the controller and this is what i got b-b 8.9k ohms b-y 4.1ohms b-g 9.88k ohms onthe red side it was r-b 10ohms r-y 8.9k ohms and r-g 18.8k ohms
[/QUOTE
Please can anyone help me
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
14,142
5,474
58
West Sx RH
The Yellow wire mosfet is faulty at 4k ohms.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
14,142
5,474
58
West Sx RH
I looked at your pics on page 1 of this thread and see it is a lishui brand, what did you replace the controller with ?
 
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gazza19

Pedelecer
Aug 22, 2020
155
3
I looked at your pics on page 1 of this thread and see it is a lishui brand, what did you replace the controller with ?
This is the new controller model as I could find the other one also these pics show the the pedal assist connections the one with the cover peeled back a bit is from the pedal assist sensor and the other is from the controller also sorry for being a pain but the brakes I got were red and blue wires i had to put connectors on them and the wires from the controller were black and white so have I connected these up right too your help is always very much appreciated
 

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gazza19

Pedelecer
Aug 22, 2020
155
3
I looked at your pics on page 1 of this thread and see it is a lishui brand, what did you replace the controller with ?
This is the new controller model as I could find the other one also these pics show the the pedal assist connections the one with the cover peeled back a bit is from the pedal assist sensor and the other is from the controller also sorry for being a pain but the brakes I got were red and blue wires i had to put connectors on them and the wires from the controller were black and white so have I connected these up right too your help is always very much appreciated
This is the new controller model as I could find the other one also these pics show the the pedal assist connections the one with the cover peeled back a bit is from the pedal assist sensor and the other is from the controller also sorry for being a pain but the brakes I got were red and blue wires i had to put connectors on them and the wires from the controller were black and white so have I connected these up right too your help is always very much appreciated
this is the controller I got i only used the controller as the one that goes on the handle bars is more or less the same the last pic is the one i have on the handle bars now
 

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