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Set-Up of HPC700 96V and 20kW BLDC Motor

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Sourcefinder:
Hi,

after having problems with the contactor of the HPC700 controller I sent it back to goldenmotor.
They repaired it - thanks a lot to goldenmotor - and sent it back including setting up the wrist throttle.

I installed it and tested it but under full speed I get only a power of around of 13 kW (measured by the battery management during use). Motor and controller should do 20kW continous and 50 kW peak power.

When the controller is switched on it makes kind of whistling noise - I guess it is because it has a little consumption of energy even if motor is not turning - you can see it on the first picture. If I had running the system with a potentiometer there was no whistling noise.

Another thing I am not sure if it could have influence on the power is that I don't use a brake.
Software says "R" for reverse gear which is ok and BRAKE. But when I move the wrist throttle it starts moving.

Attached I post screenshots of my set-up.
Do you have any idea why I get only 13kW power?
Battery is 30 pcs Winston 100Ah which is in idle around 100 Volt.
Current under full speed is now around 130 Amps.

Thanks!
Best Regards
Hermann

Sourcefinder:
next pics attached

Sourcefinder:
last pics

Bikemad:

--- Quote from: Sourcefinder on December 08, 2016, 08:18:04 PM ---Do you have any idea why I get only 13kW power?
Battery is 30 pcs Winston 100Ah which is in idle around 100 Volt.
Current under full speed is now around 130 Amps.
--- End quote ---

Hermann,

Assuming the motor is reaching the expected maximum rpm for the voltage being used, then the motor will only draw as much current as it needs to overcome the torsional load on the impeller shaft.
If you were to place more load on the motor, then the current being drawn would also have to increase to maintain the same rpm.

Also, the petrol engine that you have replaced would have developed its maximum torque somewhere near its maximum rpm (which is probably at a higher rpm than your "3000-5000rpm" electric motor) whereas the electric motor you are using develops its maximum torque at low rpm, and it usually reduces as the revs increase. ;)

With a car (or motorcycle) you would simply select a higher gear ratio to place more load on the motor, but I'm guessing you have a direct 1:1 drive to your impeller on the jet drive propulsion system.

You may need to use some form of overdrive gearing between the motor and the impeller to allow it to spin the impeller faster than the motor shaft.
Doubling the impeller speed (by fitting a 1:2 gear ratio gearbox) would probably draw four times as much current to achieve the same motor rpm.

Alan
 

Sourcefinder:
Hi Alan,

thanks for your feedback.
I had a look on the motor data and the gasoline-engine's data.
You are right, I need a gearbox 1:1.5

Did not know that the motor increases torque to zero around 3500-4000 rpm....

I'll tell you once I have installed a transmission.... maybe chain pr belt system with different wheels for testing....

Thanks a lot!

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