HPM3000 motor with VEC200 controller, won't give initial torque, very low

[Prongzz]

Hi,
I am having problem with HPM3000motor 48v(VEC200 controller).
The problem is, motor is not able to give sufficient initial torque. It gives good speed after couple of seconds but, auppose I am trying to move bike on inclined slope, it won't move, controller cuts off the supply with blinking red led.
Any thought what am I doing wrong?
 

[Bikemad]

Hi andto the forum.

If you can provide a bit more information on your bike conversion (i.e. overall gear ratio, tyre diameter, battery type, voltage and continuous/maximum current ratings, overall weight etc.) it would help to understand what might be causing the problem.

I suspect that your starting phase current setting (or battery drawn current) may be too low, or the gearing between the motor and the driven wheel is simply too high and overloading the motor from a standstill.

Does the blinking led blink three times or four times?
Three regular flashes is an indication of excessive Current (which can be due to problems with the motor windings), whereas four regular flashes usually indicate Stall Protection has been triggered because the motor has been stalled for too long (possibly due to excessively high gearing).

If you can also post some screenshots, or provide details of the current controller settings, this could also be very helpful. 

Alan
 

[Prongzz]

Hi,

I am working on EV project, and using HPM3000motor With VEC200 controller, I am getting very low torque, would you please guide me through controller parameyer settings to achieve intiap toruqe....thanks and regards.

[Bikemad]

If you can provide a bit more information on your bike conversion (i.e. overall gear ratio, tyre diameter, battery type, voltage and continuous/maximum current ratings, overall weight etc.) it would help to understand what might be causing the problem.

You first need to help us by providing the requested details of your setup, and then we can hopefully help you to solve the low torque problem.



Alan
 

[Prongzz]

We needed around 95 Nm torque on wheel of 12 inch so used 4.5 gear ration considering 21Nm motor torque as per the golden motor sheets.
But we guess the problem is with controller as we tested the motor with another local unprogrammable controller and motor was giving the required torque.
And as you said we increased the value of starting phase current to max and the performance was improved a bit but not that much compared to other controller. So can you guide with the controller settings (specially current settings) and give a bit info regarding stall, boost functions.
Also one more thing that the default rotation of our motor is in reverse direction so we have changed the U & W wires and using it..

[Bikemad]

This is the bit that concerns me the most:

The default rotation of our motor is in reverse direction so we have changed the U & W wires and using it..

In addition to swapping the thick Blue (U) and Yellow (W) Phase wires, the thin Green and Yellow Hall sensor wires must also be swapped.
If you have not swapped the Green and Yellow Hall sensor wires, you need to do this to enable the motor to run correctly, as this could be the main cause of the low torque. 

The maximum current settings will be determined by your battery's maximum and continuous current rating.
If your battery is not capable of delivering 80A, the Battery drawn current limit (A) should be reduced to match the battery's maximum current rating.
I seem to recall that the Rated phase current (A) should be set about 30% higher than the Battery drawn current (A) (i.e. 80A battery current x 1.3= 104A) but I think some trial and error may be necessary here to obtain the best performance without overheating the motor or controller.

I have not seen any information from GM regarding the Boost and Stall functions, but they are obviously intended to protect both the battery and motor from being unnecessarily overloaded.
If you battery has a burst current rating of xx Amps for xx seconds, I would try to adjust the available boost settings (and possibly the Maximum phase current duration (s)) based upon these figures.

Your stall protection time(s) is currently set to 2 seconds, but it might be necessary to increase this slightly if the motor is still cutting out from a standstill (with the correct Phase and Hall wire configuration), as this should allow the motor more time to initially speed up.

Also, I hope that your torque requirement of 95Nm at the wheel is only required at speeds below 12mph (~20km/h), as the motor is not likely to produce this amount of torque above 1500rpm on a 48V battery.

Alan
 

[Prongzz]

We have changed the phase and hall wire combinations as you suggested and ran the motor. But the initial torque problem is with current limitations. As mentioned we got much higher torque with another local hardcoded controller which gives the torque on your motor we desire.Currently we are using VEC 200 controller. if we go for VEC 300 which has rated current of 120 A, will it give better torque?

And yes our battery is capable to provide upto 140A if we draw by 2C, but we have capped it passively for 100A.

[Bikemad]

If the VEC-300 controller can supply 50% more current than the VEC-200, then the motor should produce 50% more torque.

I don't know why the GM controller produces less torque than the other controller you tried, perhaps it is the 80 Amp limit.

I noticed that the dynamometer results for that particular motor shows the current draw going up to almost 95 Amps, which means they were probably not using a VEC-200 controller for those tests.

Did you have any means of measuring how much current your other controller was drawing under load when it produced the additional torque?

I also noticed that at 2~3kW output (the rated power output for that motor), the motor is only producing 4.5~7Nm of torque, which would be 20.25~31.5Nm of torque at the wheel with your 4.5:1 gear ratio. This is only 21~33% the 95Nm of torque that you said you needed.

Perhaps this 3kW motor is simply too low in power for your particular needs. 

Alan