motor wont spin stops every quarter turn

[splitfire]

hi i am new to this forum. My bike was running fine. my bike was recently running a lifepo4 24s @88v the battery is old it only carry 30% so i replaced it with 9 turnigy 6s 5000mah and 3 tunigy 3s 5000mah to match the 88v. i connect 3x 6s lipo plus 3s that gives me 21s and connected it in 3 parallel to make 15000mah.
my bike runs like new. i run it about 30kms then my rear tire got flat. so i took it home to replace my flat tire and then when i start it, it wont start anymore. When i turn it on cycle analyst is working fine, but when i twist the throttle the wheel wont spin even if i pedal start it still wont spin. I notice that when i spin the wheel it wont spin freely its like it applies brake every quarter turn. I disconnect the 3 phase wire and spin the tire. It spins freely good. alternating those 3phase wire, i connect and disconnect and found out that when i connect the green phase wire it stops every quarter turn. So there is a problem in my green phase wire connection. I check my crystalyte controller all solder are good everything is intact, no burn, no capacitor bloat, nothing abnormal, check throttle connection it reads out 5v when i twist which is good. check all the connections form my crystalyte controller to every end points of the connectors check for zero reading and they are all good. Now i dismantle my hub motor check the windings, magnets, bearings, 3phase wire 3 hall sensors and its all intact no faulty wirings......Any suggestion guys. i am pretty sure that i didnt overload my controller coz i am using the same voltage. (note: when i hand spin the rear wheel it stops every quarter turn feels like the magnet reacts even the controller is of "battery disconnected")

 

[Hwy89]

Check for a short circuit between the phase wires. Follow the wires from the controller to where they connect with the wires at the hub and look for chafed rubbed or kinked areas. It is likely that you have physical damage to the insulation and two of the phases are shorted.

 

[splitfire]

hi just wondering if it is possible for you to check what reading do you get on your 3phase wire and hall sensor using multitester. I am having a problem my motor wont spin freely even the battery is not connected. I suspected the motor but i opened it and everything looks good. just want to compare what reading do you get. thanks.

 

[splitfire]

is it right? i measured the 3 phase wire i get a reading of zer0 resistance from each of them green to red to yellow. I dont know if it is suppose to be like that or if not. What will be the reading suppose to be? If i have a red light up in my controller does it means its working fine?

 

[NeilP]

No need to check exact figures, can tell you close enough what they should be.

If it not spinning freely and it is not a mechanical issue then the only cause is damaged phase wires.

also going to depend on how accurate your resistance meter is as to if you can measure the short.

Best you can check for is to see if any phase wire are shorted to the case / axle.

Measuring a short between phases with no short to earth is difficult unless you have a high accuracy meter, as you are measuring difference between winding resistance. which is near enough zero, or a short on the phase wires which will be much closer to zero.

I can't get accurate figures for the moment, sorry

 

[NeilP]

If you have continuity between any phase wire and any of the 5 hall wires of the axle, then you do have a problem with broken wires/insulation

 

[NeilP]

Another thing to check if you take the motor apart again isn the bearings.

it depends on what the 'stiffness' feels like.


My new 5304 was very hard to turn, but it turned out it was the bearings . One of the side covers was badly machined, so when the bearing was pressed in to it, it partly seized up, it really bound it up.

had to polish out the inside of the bearing housing in the lathe to get a better bearing fit.

 

[kentlim26]

the ball bearing does look quite age, and rusty. if is possible , change a new one. spray some w4d and always grease , lubricate. it must able to turn smoothly and easily. i hope it helps you

 

[John in CR]

There was no need to open the motor, but since you did, it's overhaul time. ie get a good coating on the stator lams and change the bearings. Let me know if you want to make some simple mods for better cooling, since there's no fan design on the planet that is essentially holes in a flat plate.

When you had the notched turning of the wheel and disconnected the phases, and it then spun freely, that told you from the connectors to the motor was fine, and the problem is between the connectors and inside the controller. It's almost surely the mosfets for the green phase, and one of the electronics guys can better tell you what to measure to be sure.

 

[splitfire]

thanks guys yup i will replace the bearing....i just dont know where to get them and the specs.....i might just use it for now once i got this fix and replace the bearing later ....bearing still spins smoothly. heres my findings in my crystalyte controller . I turn the power on check the volatage across positive and blue phase wire i got 84vdc, positive and yellow phase wire i got 84vdc. positive and green phase wire i got no voltage nothing.....I turn off the switch test the resistance reading positive and blue phase wire got infinite, positive and yellow phase wire infinite, positive and green i got zero resistance (grounded?)

 

[splitfire]

hey guys. My ebike just stop working. I opened up my motor and i havent seen any damage. all the wires and solder are really good. Now i opened up my controller and test the phase wire and this is my findings in my crystalyte controller . I turn the power on check the voltage across positive and blue phase wire i got 84vdc, positive and yellow phase wire i got 84vdc. positive and green phase wire i got no voltage nothing.....I turn off the switch test the resistance reading positive and blue phase wire got infinite, positive and yellow phase wire infinite, positive and green i got zero resistance (grounded?) is it worth to fix or to buy a new controller how much?

 

[splitfire]

thanks Neil. you are right its really hard to measure the resistance between phases i should have really accurate device to measure it. I found out that my motor is good and i suspected the controller. I opened up my controller and test the phase wires and this is my findings in my crystalyte controller . I turn the power on check the voltage across positive and blue phase wire i got 84vdc, positive and yellow phase wire i got 84vdc. positive and green phase wire i got no voltage nothing.....I turn off the switch test the resistance reading positive and blue phase wire got infinite, positive and yellow phase wire infinite, positive and green i got zero resistance (grounded?) is it worth to fix or to buy a new controller how much?

 

[NeilP]

Just test with power off.

First disconnect the battery pack, no need to test with power applied.
Set resistance mode
Then connect red lead of meter to negative and test all phase wires.
then swap the red lead of the meter for the black lead, on the negative again, and test phases again.

Then do the same, again, this time using the meter tested to the positive controller battery lead.

But it does sound like a FET (or FETs) has (have) blownen .

Can be a job you can do yourself if you have big enough soldering iron and patience.

Trouble is you can't just remove one FET, unless you can see it has burnt. You will need to remove all FETS from faulty channel and test them all . Test them as they come out, you may get lucky and remove the dud first time . If you find you have removed the dud, check the board again incase more than one is blown.

Then replace, checking for solder bridges etc.

But then once you do all that, it is still possible it won't work as it is possible one of the SMD gate drivers has blown.

 

[splitfire]

Problem solve and fix ...green phase shorted. 3 mosfets on high side was replaced.