Reversing BLDC motor standard rotation.

[EV1030]

Reversing BLDC motor standard rotation.
Is it possible to change the standard rotation of a 96VDC BLDC motor (VEC500 controller) by changing the wiring or by updating the program?  The project is a Motorcycle conversion and requires the forward direction to be counter-clockwise while looking at the drive end of the motor.  Currently the controller is being run in reverse in order to get the motorcycle to drive forward.  Since the controller has to be run in reverse to get to motor to go the right direction for the motorcycle which then never allows for the regenerative braking to work.

[Bikemad]

Hi andto the forum.

It should be possible to change the default direction of the motor by swapping two Hall sensor wires and two Phase wires, but make sure the battery is disconnected before you touch any wires.

I would suggest swapping the Green and Yellow Hall sensor wires and the Green and Yellow Phase wires and carefully apply slight throttle to see if it runs smoothly in the opposite direction.

DO NOT APPLY TOO MUCH THROTTLE IF THE MOTOR IS DRAWING MORE CURRENT THAN IT DID BEFORE OR RUNS ROUGH, as this indicates that the Phase wire combination is incorrect and could overload the controller.

If it does not run smoothly, or is drawing high current, leave the Hall sensor wires alone, but swap the Green and Yellow Phase wires back to their original positions and try swapping the Blue and Yellow Phase wires instead, and then try a small amount of throttle again.

If it still does not run smoothly, or is drawing more current than it did before, leave the Hall sensor wires alone, but swap the Blue and Yellow Phase wires back to their original positions and then try swapping the Blue and Green Phase wires.

Hopefully one of the above combinations will work correctly.



You might also want to take a look at this post regarding permanently changing the direction of a Magic Pie 5 motor (this uses an internal Vector controller).

Alan
 

[EV1030]

Hi Alan,

So far I have tried swapping the Blue and Green phase with and without changing the Hall effect sensors and tried the throttle but the motor either hums or cogs forward a little.  I have tried swapping the Yellow and Blue also.  I will try a few more combinations tonight.  When swapping the hall effect sensor wiring do you need to swap the wire pairs or just the matching phase colors?  Once I have it figured out I will post a revised drawing for others with the same issue.

Regards

[Bikemad]

To reverse the default motor direction of a BLDC motor you must reverse two of the Hall sensor wires and the correct pair of the Phase wires (only one of the three phase wire swap options will work correctly).

It is probably easiest to swap the Green and Yellow Hall sensor wires in the 6 pin connector near the motor instead of the 30 pin connector on the controller.
But if you are unable to remove the pins (or sockets) to swap the two wires over, you may have to resort to cutting the Green and Yellow Hall sensor signal wires (on either the motor or the controller harness) and then solder them to the opposite colours.

However you decide to do it, make sure that you connect the Green Hall sensor wire from the motor to the Yellow Hall sensor wire in the controller (Pin 13), and the Yellow Hall sensor wire from the motor to the Green Hall sensor wire in the controller (Pin 12).

With a BLDC motor there are 36 different possibilities of Hall Sensor and Phase wire combinations, and out of these 36 combinations, three should work correctly in the forward direction and three should work correctly in the reverse direction.
The other 30 incorrect combinations should not be used.

By swapping one pair of hall sensor wires (e.g. Green and Yellow) you should only need to try a maximum of three phase wire swaps from their original position to find the working combination.

It should also be possible to find a working combination by swapping any two Phase wires and then trying the three different Halls sensor wire swaps available from their original positions, but as the Hall sensor wires are more difficult to swap than the bolt on Phase wires, it makes sense to swap two of the Hall sensors only once, and then find the correct matching combination of Phase wires. 

Standard Phase wire configuration:

U = Yellow
V = Green
W = Blue 

Only one of the following Phase wire options will work correctly with the Green and Yellow Hall sensor wires  transposed:

• Green and Yellow Phase wires transposed
  U = Green
  V = Yellow
  W = Blue
   
  
• Blue and Yellow Phase wires transposed
  (This is the working combination for the 10kW BLDC motor with the Green and Yellow Hall sensor wires transposed)
  U = Blue
  V = Green
  W = Yellow
   
  
• Blue and Green Phase wires transposed
  U = Yellow
  V = Blue
  W = Green
   
  

I hope this all makes sense.

Alan
 
EDIT: Working combination confirmed.

[EV1030]

Thank you Alan!!!   Sequence #2 did the trick and what a difference it made. The regenerative braking works perfectly.
The set points of the controller may need to be adjusted to get better performance. Is there any information on the set points of the different parameters?
Thanks for the help!

[Bikemad]

It's good to hear that you've now got the motor working correctly in the opposite direction.



If you could find the time to post some information and pictures/video of your bike it would be appreciated, as it would be interesting to see how the conversion has been carried out.

Is there any information on the set points of the different parameters?

Unfortunately there is no documentation available for the VEC controllers that explains the various setting options, but some of the parameters do contain useful information (minimum and maximum values etc.) displayed in the pop up tool tip box when you click (and keep the cursor on) each of the parameters in the programming software.

Alan
 

[EV1030]

Hi Alan,

Here is a picture of the motorcycle.

Regards

[Bikemad]

It looks like you've done a really nice conversion there, but how does the acceleration and top speed compare to the original ZZR600?

Can you still lift the front wheel with the throttle, or is the 10kW motor not powerful enough?

Alan
 

[EV1030]

Hi Alan,

The motor has lots of torque but since there is no 6 speed transmission the acceleration off the line for the first 3m is slow but starts to pick up very fast.  The top speed so far was 110km/h with the 2 x 48VDC 30Ah batteries and the controller max battery discharge set at 90Amps.  I will be upgrading the batteries to 80Ah with a continuous discharge of 216Amps which should really increase the performance.  I will keep adjusting the program for better acceleration off the line.  As of now the motorcycle out accelerates most cars, minivans and trucks.  We plan to get some video of the motorcycle on the road to show how it handles and accelerates if traffic.

Regards

[EV1030]

Hi Alan,
Second prototype is finished and I'm now fine tuning the controller. I would like to know if there is a way to get quicker acceleration off the line?  Could you advise on some settings like throttle and starting current.
Thanks.

[Bikemad]

Unfortunately I have not had any first hand experience with the VEC-500 controllers, so I'm not sure what parameters are even available for altering, or how high (or low) they can be set.

You will have to experiment with the settings to find out the maximums that the acceleration, battery and phase current can be set to without overloading either the battery or the motor.

The motors on my Vectrix electric scooters are rated 20.2 kW (27.1 hp) peak and 7 kW (9.4 hp) continuous, but they are very slow initially off the line. I assume this has been done deliberately to avoid losing the back end due to wheelspin in wet conditions, but I suspect that the reduced power on the initial acceleration also makes a noticeable difference to the overall range of the battery when subjected to continual stop/start city style riding.

Alan
 

[EV1030]

Hi Alan, 
I just purchased the 96vdc 300A contactor. What is the coil voltage?  I though it was 12Vdc across A1 & A2?  A1 positive switch by ignition and A2 negative.
Thanks

[Bikemad]

To be honest, I'm not sure what the coil voltage is, but I would expect the coil of a 96V contactor to be suitable for 96V use not 12V (unless it was specifically marked as a 12 V coil).

The circuit diagram for the HPC controllers does not mention any voltage for the contactor coil, just where they connect:



But I cannot find any diagrams for the VEC controllers that show how the contactor coils should be connected.
I suggest you contact Andy at GM China and ask for his advice on this matter:


Ideally, the contactor coils should be automatically energised by the controller, but only after the controller has satisfactorily completed its Power On Self Test (POST) routine and the capacitors in the controller have also been charged up at a low current until they are almost equal to the battery voltage.

Most contactors will consume around 7~15 watts of power to keep the coil windings energised, so measuring the resistance of the contactor windings should give a rough idea of their voltage rating.
A typical 12V contactor coil will probably have a resistance of 10~20 Ohms, whereas a 96V contactor coil is more likely to have a resistance somewhere in the range of 500~1500 Ohms. 

Check out this thread for more details on contactor voltages.

Alan
 

[EV1030]

Update
Coil measures 67ohms
Case is marked 96vdc
Put 96cvd across A1A2 and Magic
Thanks again for the support.

[Bikemad]

67 Ohms seems a bit on the low side.

96 Volts/67 Ohms = 1.433 Amps

96 Volts  x  1.433 Amps= 139 Watts

139 Watts would generate a lot of heat inside the contactor windings.

Perhaps the GM contactor has a pair of windings (one high resistance and one low resistance) wired in parallel to initially energise the solenoid, and only uses a single (higher resistance) winding to keep the solenoid engaged.

I also got some resistors with the contactor....

Was your contactor supplied with separate resistors too? If so, what are their resistances.?

I would consider carefully measuring the holding current with an ammeter to check if it drops a lot lower than the calculated 1.433 Amps.
Be very careful with the high voltage as 96VDC could kill you.
(Dependent upon the battery type, the actual voltage of a fully charged 96V battery could be anywhere between 104V and 118V!)

Alan