3kw bldc motorcycle conversion issues/questions

[Motolittle]

Hello my friends, this is my first post to this forum.

I recently just purchased the 3kw 72 volt golden motor bldc and the corresponding 72volt 220 amp vector speed controler. I also purchased a 72 volt lithium-ion 18AH pack that has 50 amp continuous BMS and 100amp max burst.

This is all going in a Yamaha xt350 frame that I am converting to work. I already aquired a 10 tooth front sprocket and a custom 67 tooth rear sprocket.

The issue I am having is that after wiring it all up for testing I am running into some issues...

When I give it throttle about 1/2 the time the motor spins and the other half of the time the motor hums a little bit and will not turn... this is all with no load on the motor... but if I move the driveshaft about a 1/8th turn it will proceed to work until stopped again and it will not go unless I turn it by hand again.

I have connected the system to a pc using the golden motor USB cable and the most current online program. I have changed parameters and settings but the symptoms do not change. I even re loaded the factory settings to make sure that was not it.

To clarify the symptom: when I plug in the battery andturn it on and  twist the throttle the motor does not spin (no load). It stutters and hums a little bit. If I spin the motor by hand a small amount and give it throttle it starts to spin and seems to work fine until it stops again and won't start till I spin it again.

I have tested my battery voltage is all good and the motor controller downloads to the computer just fine and seems to be working properly. My question is in the motor. I have tested the Hall sensors with a voltmeter and am confused with my reading. Normal Hall sensors are either off at 0 volts or on about 5 volts when the motor is spun by hand. My readings are as followed for all 3: off voltage is measuring .012v for all sensors and only 3.042volts. To me it seems that all the Hall sensors are bad...  but this is a brand new motor.

I can post my parameters from the programming if needed but at this point I need help to figure out what it is. I can test anything you all may want me to test. Thank you in advance for your help

-nick

[Bikemad]

Hi Nick andto the forum.

When the motor refused to turn on its own, did you notice any regular flashes from the controller's LED indicator light, if so, how many regular flashes were there?

Are you using a GM throttle?
I'm not sure if an incorrect throttle might put too much load on the +5V supply which could account for the lower voltage reading on the motor's Hall sensors, as I would be very surprised if all three of the Hall sensors were "bad". 

It would be interesting to see what the voltage reading on the +5V feed to the Hall sensors was.

Check that your Phase wires are connected to the correct terminals on the controller:
The standard Phase wire configurations are shown below:

U = Yellow
V = Green
W = Blue 

If you need to reverse the motor's default direction of rotation to suit your particular installation, take a look at this post for more details.

Alan
 

[Motolittle]

Thank you for the swift response!

The only blinking from the controller is the single blink when I power on using the e-lock. It does not throw any codes that I have seen. The throttle I am using is the standard golden motor 48 volt full twist throttle. I know I use the 72 volt system but Gary from golden motor Canada (where I purchased everything) said that was the only throttle they offer and just not to use the LED battery indicator.

When the motor doesn't spin (under no load) it just hums a little and won't move till I turn it with my hand than it spins up but still seems weak to me for what the system is supposed to be.

Does a 72 volt 18ah battery sound insufficient for this system ? I don't think the battery is the cause of the motor not wanting to spin.

Also my phase wires are all correct to the diagram and my motor spins in the counterclockwise directions when it wants to spin. Is this normal motor direction?

What are some other ways to test the motor... and the Hall sensors? I am trying to do all testing that I can because I don't want to return it but will if I need to. Thank you so much.

[Bikemad]

The GM throttle should be fine with the LED battery gauge disconnected, and the battery should have adequate output for a 3kW motor (72V @ 50A = 3.6kW and @ 100A = 7.2kW).

Check out this topic regarding a similar setup with intermittent starting.
Unfortunately, we never found out what was causing the problem as the original poster stopped responding. 

It is difficult to say whether the humming is due to an incorrect Phase wire/Hall sensor configuration, controller fault, or possibly a very low starting current, but something is definitely wrong.

I would have expected the motor to run in a clockwise rotation (when viewed from the output shaft end) which is opposite to what you have described. 

I also recall a similar problem regarding occasional non-starting of a 5kW motor (but only when it stopped in certain positions) which turned out to be a faulty controller.

You can perform a simple test on the phase wires and stator windings by disconnecting the phase wires from the controller, touching any two phase wires together, and then trying to spin the motor shaft by hand.
If the two phase wires (and windings) are all OK, the shaft should be difficult to spin as the shorted phase wires will cause an electromagnetic dynamic braking effect.
The level of resistance should be identical with all three combinations of pairs touched together (Yellow/Blue, Blue/Green and Green/Yellow).

I have not tried this, but it might be possible to measure the voltage output on the phase wire terminals of the controller (with the Hall sensors connected, but the phase wires disconnected) by applying the throttle while turning the motor by hand.
If it works, I would expect the voltage reading to be similar (and the polarity of the reading should also alternate every 45 degrees) with all three combinations of pairs being measured (U/V, V/W and W/U).

This might not work as the controller may simply produce an error code if it is unable to sense any current flow because the phase wires are not connected, but if it does, you might be able to home in on any anomalies (e.g. if one pair has a different voltage reading or does not change polarity as expected etc.)

If you cannot find anything obvious, perhaps Gary could test your controller on another motor to check its operation.

Alan
 

[Motolittle]

Thank you Alan for the Info.

I tested the motor windings as you described and they all feel similar and no irregularities.

I changed around the phase wires from standard configuration because standard phase setup  was spinning counterclockwise for me and 1 configuration did not work but 1 configuration did work and made the motor spin clockwise as you said. I am leaning towards the Hall wire and phase wires not being right as my problem as of now but I need to test more.

Unfortunately I could not connect the motor controller to the computer because I kept getting time out error... never had that before...

I will keep testing and will need to put it into counterclockwise rotation no matter what so I will have to mess with the Hall wires.

If you think of anything else let me know and I will hope to post back soon!

[Motolittle]

Also what should the Hall sensors voltage be if I measure it by spinning the wheel with the system plugged in? Thx. I believe about 0 volts in off stage and 5 volts in on stage. Please feel free to correct me if I'm wrong. Thank you again in advance

[Motolittle]

Without reconfiguring the Hall sensors I changed the phase wires to:
U=green V= blue W= yellow.

Now the motor spins in the counterclockwise direction.... but it doesn't seem to have any issues where it doesn't want to start.... does this make any sense to you? The Motor also seems like it has more power... but of course I need it to run in the clockwise direction for my application. But I don't understand why the factory wiring was spinning in counterclockwise but not wanteing to always spin.

[Bikemad]

If a reverse switch was connected and turned on (or the two reverse wires were touching each other) this would cause the counterclockwise rotation of the motor, and might also prevent the controller from being programmed. 

As you now seem to have the motor running correctly (albeit in the wrong direction?) it might be that the Hall sensor wires and/or the Phase wires may have been incorrectly colour matched during assembly of the motor.

Now the motor spins in the counterclockwise direction... but of course I need it to run in the clockwise direction for my application.

Are you sure that you need clockwise rotation? As the chain and sprockets are both on the left hand side, they should both rotate counterclockwise to drive the bike forwards.

However, if you do still need to reverse the motor's direction, I would simply swap the Green and Yellow Hall sensor wires over and then find the correct matching combination of Phase wires.

As your current Phase wire configuration is:

U = Green
V = Blue
W = Yellow

One of the three following Phase wire options should work correctly with the Green and Yellow Hall sensor wires transposed:

• Green and Blue Phase wires transposed
  U = Blue
  V = Green
  W = Yellow
  
  
• Green and Yellow Phase wires transposed
  U = Yellow
  V = Blue
  W = Green
   
  
• Blue and Yellow Phase wires transposed
  U = Green
  V = Yellow
  W = Blue
  

Also what should the Hall sensors voltage be if I measure it by spinning the wheel with the system plugged in? Thx. I believe about 0 volts in off stage and 5 volts in on stage. Please feel free to correct me if I'm wrong. Thank you again in advance

The maximum Hall sensor output voltage will vary in relation to the +5V supply. If the +5V supply is ~4V, then maximum the signal output will be even lower than the supply voltage (less than ~4V). The important check is that they all alternate between high and low voltage as the motor is rotated slowly.

If your motor runs smoothly and there are no dead spots (positions where it can't self-start) your Hall sensors must be working correctly. 

Alan
 

[Motolittle]

Alan sir you are a gentleman and a scholar!!!! Combination # 3 worked!!! I will report more later. Now I can proceed with the build!!  THANK YOU FOR YOUR HELP!!!

[Motolittle]

Well guys after much building and progress forward I have ran into another issue..

I have had the whole system working for a few months! To Be honest this whole system has ran great! I now have a 14:1 gear ratio so no motor getting hot or speed control hot or battery hot.

After a ride today the bike quit working so I unplugged it immediately. Upon re plugging in to diagnose the battery arced pretty bad and the BMS cut power to the speed control.

Next I tried to push the bike as I had it unplugged and it was so hard to push like regen was on....

So I unplugged the motor and it began to spin free again. I checked all connections and all wires for continuity and the oddest thing was I had continuity between the input blocks on the speed control. ... I unplugged everything but the battery and speed control and no matter what I do the battery BMS shuts off power because something is shorting in the controller.

I don't get it for sure ... I tried to connect a computer to the motor controller via my USB link and it would not show up at all...

Any help would be appreciated!!

What we know: battery still good
Motor spins free and phase wires when touched in pairs slow motor equally each combo.

Motor controller : Vector 200 72 volts not responding to voltage at all and shorting on input terminals

Throttle: standard gm throttle 48 volt. Have not tested yet unsure how.

Please help and thanks in advance !!!!!
Throttle

[Bikemad]

If it is is hard to push with the battery unplugged, it sounds like at least two of the controller's MOSFETs could have failed in a short circuit state.
If they have both shorted to Positive (or both shorted to Negative) this will effectively produce a direct short circuit across the two Phase terminals:



This would result in two of the three phase windings being shorted together through the two shorted MOSFETs on the same (Positive or Negative) rail.

This would give explain why it was so hard to push like regen was on.

Unfortunately, I think a replacement controller (or controller repair) will be required in order to get your motor running again. 

If the controller is still under warranty, you will need to contact the supplier to see what needs to be done.
I suspect that the controller will need to be returned for either repair or replacement under the warranty.

Alan
 

[Motolittle]

Thank you! I guessed that was going to be your guess as I already figured it was definitely the controller.. bummer!


Is it possible for me to repair the internals on that controller or no?

Also I see a fuse in the diagram you sent. How can I change my system to easily prevent this again? I know my battery is not even close to max of this controller. 18.5 ah 3c li ion 72 v pack.

Also what could have caused this literally mid riding. The only thing I can think of is maybe I bumped the e lock button on or off while I was riding . This has happene before to me but never caused an issue. .

Thank you again for helping everyone!

[Motolittle]

Or do you think it was caused by me overloading it by applying manual brakes and doing too many rolling  burnouts  

Like I said I am very impressed with this system so far I just want to keep riding with it and further prevent it

[Bikemad]

Is it possible for me to repair the internals on that controller or no?

Also I see a fuse in the diagram you sent. How can I change my system to easily prevent this again? I know my battery is not even close to max of this controller. 18.5 ah 3c li ion 72 v pack.

Also what could have caused this literally mid riding. The only thing I can think of is maybe I bumped the e lock button on or off while I was riding . This has happene before to me but never caused an issue.

I have no idea as to what is involved in repairing the VEC-200 controller as I have never seen inside one, but as long as the damage is confined to just the MOSFETs, and suitable replacements can be acquired, then you may be able to repair it if you have sufficient soldering equipment, skills and/or experience. 

The diagram  was only posted to give a rough idea of a typical MOSFET power circuit, basically to help you visualise how short circuited MOSFETs would affect it.

As your battery has a BMS to limit the maximum current and (presumably) the VEC-200 controller also has an inline fuse already attached to it, then your installation should be adequately protected against current overload.

Disconnecting the battery while under load or during regen can cause problems with controllers, but I'm not sure how the e-lock system operates. If it simply prevents the motor from being powered up (similar to disabling the throttle) without disconnecting the battery, then I don't see how it would cause a problem.

Or do you think it was caused by me overloading it by applying manual brakes and doing too many rolling  burnouts

Whilst burnouts will obviously be working the controller quite hard, I would still expect the controller to be adequately protected by the maximum permissible current settings that it will allow to be entered.

Alan
 

[Motolittle]

Correct! The vec200 has a built in 100 amp fuse on the input terminals which is not blown and the battery BMS is 50 amp continuous BMS and 100 amps max out put if it can even hit that... being only 18.5 amp hr battery. ... the vector 200 should be able to take up to 200 amps what it's rated for correct? Maybe I mis understood it.

I do not use a contactor in my system and I only use the e lock on the throttle as my main system on and off. So my only thought like I said is maybe while I was riding I turned it off which has happened by accidentally hitting the e lock button ... still not sure if that's enough to burn it up...

Still I don't think it's the burnouts because it is a pretty robust system and that's all I have been doing for the last couple months.

Nothing was hot or seemed overheated.

I will contact my supplier regardless