Here, we test the Cute Q-85SX hub motor on my motor test stand. With this we can create among others the torque/speed curve.
- Motor 1.76 kg
- Cable 1.57m 0.08 kg
- Total 1.84 kg
- Thread M12x1.25
Measuring motor parameters
This is done HERE.
- R = 0.307Ω
- k = 1.57
- Friction torque Tf = 0.82Nm
Motor current on the scope
Many hub motors don't have full specifications, but the Cute Q-85SX is an exception, the manufacturer delivers the motor graphs.
An application of irradiated cross linked PVC wire
Because the motor cable goes through a small hole, the insulation should be very thin. Therefore cross linked PVC wire is used, see the article here.
Motor load test with the test bench
The data from the test bench are processed in this Excel sheet.
- The motor is tested inclusive the motor controller KU63.
- The motor controller current limit value is changed from 12A to about 20A.
- The motor is used without the Hall sensors.
- The measurements are done inclusive the motor connection cable which is 24mΩ per phase.
- The accuracy of the test bench is about 5%.
Calculated motor graphs
On basis of the motor parameters, the motor efficiency graph can be created too. See THIS Excel sheet.
We clearly see that both graphs are almost identical in the linear range 0 ... 18Nm.
Note that in order to fit the calculated graph, the gearbox efficiency is set to 94% and the motor temperature set to 50°C.