# What is the effect of undervolting BLDC motors on its RPM, Torque, Current?

What is the effect of undervolting BLDC motors on its RPM, Torque, Current?

I currently own some ODrive 6374 48V 150KV 3.86NM 70A motors that I plan to use for my project. But due to some constraints that are out of my control I can only use 24V as my power supply.

So I wanted to ask how this would affect the Torque and Current of the motor? What kind of performance can I expect? Can this create issues of any sort?

My only current understanding is that the Max RPM would reduce by half.

Less speed but that’s it, the torque is based on current

Motor resistance is on the order of 100 milliohms so you won’t see a decrease in the current the motor can draw

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The ODrive has 39milliohms resistance. If the max current is 70amps, am I right to assume the max torque would be consistently 3.86Nm if the voltage is above 70*0.039 = 2.73V. As the voltage would drop below it would the max torque become less than 3.86?

Give or take a bit of loss and whatnot that’s pretty much it, as long as you stay above a 11% duty cycle the torque will be the same

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