I’ve purchased the tarot 4108 similar to the 4008 in the Odrive motor spec example sheet. I find in it max voltage is pre set to 24V. Is this correct or could it also be 36V or 48V? They are blue field that can be changed at will but I would expect it lists the max already… Right?
The rated voltage for hobby motors relates to their maximum mechanical speed - If you were to use a ‘dumb’ controller like an ESC, then it could easily overspeed the motor if you used a higher voltage.
With a closed-loop controller like ODrive, you don’t need to worry about exceeding the voltage rating. A motor designed for use with an ESC at 24V will happily work at 48V with ODrive.
As always, thx towen…
I’ll take the 48V then as it keeps currents for same torque lower, so it’ll run cooler right?
My question would then however be if it is ok to put in parallel a DC-DC converter to the main power supply of the 48V running the motors to 24V as well to power other electric components (including some steppers). Or better have two separate power supplies?
For the same motor, i don’t think you’d see much difference in temperatures between running at 24 or 48v bus voltage. For the same torque, the motor windings will have the same current, whatever the supply voltage. There would be less current in your supply wiring though and in the DC parts of the ODrive board, but that should be a minor contributor to heat.
The main advantage of running a high bus voltage is torque bandwidth - being able to change torque in a millisecond for a high performance servo requires a bit of voltage headroom.
As to DC DC converters, i see no reason not to have one piggybacking off the other, if that’s cheaper/easier to do, and it may help prevent ground loop issues between two mains power supplies.
Ahh Ok, learned from you again ;-)! THX.
I have to think about it and compare:
24V with 1000W
48V -1000W and a DC - DC to 24V.
24V - 500W and a 48V -500W.
Homework to be done. THX!