I don't know whether the 48V and 72V controllers are physically different or whether it is just the default programming that determines which is supplied when you order them.
If the controller is able to run on 72V, it should automatically populate the relevant voltage settings when you change the Nominal battery voltage setting.
If the controller is physically unable to run on 72V, I would not expect the 72V option to be available from the dropdown box menu.
The 48V and 72V HPM5000 motors definitely have different stator windingsaccording to the specifications:
Phase Resistance (Milliohm): 6.2/48V; 12.0/72V; 36.0/120V
Phase Induction(100KHZ): 68uH/48V; 154uH/72V; 504uH/120V
Speed: 2000-6000rpm (customizable)
A 48V motor running on 72V should have a 50% higher maximum unloaded rpm
(e.g. 6,600 rpm instead of 4,400 rpm).
The 48V motor should run OK on 72V as long as you don't try to push too high a current through it and cause the winding to overheat.
As the HPM5000 motor has a built in temperature sensor, if you make sure that you have the
Motor overtemperature protection enable set to
1:Enable it should not
(theoretically) allow the motor to overheat and damage the windings.
Unfortunately, I don't know how well the controller's MOSFETs will cope with switching the increased current load caused by the lower resistance of the 48V motor's stator windings.
The only other problem I can foresee is the greater centrifugal/centripetal force acting upon the magnets at high rpm.
If it's being spun faster than 6,000 rpm and one of the bonded magnets detaches itself from the rotor, it could cause considerable damage inside the motor.
Alan
