Page 1 of 1

QS 120 2000W phase to phase resistance

Posted: Jan 14 2020 12:46pm
by twikis
Because I want to heavily abuse :D (meaning, run it a much lower voltage than it's designed for) this motor, I'd love to know the phase to phase resistance of it, to determine if it'll be able to handle the acceleration + uphill power I need from it... Has anybody got one of these, and could help me out here by measuring it? Sales support at QS motor really wants to keep this a secret, for some reason.

If you've got a bench supply with current limit function + a multimeter, it's super easy to do:
1. unplug 2 of the 3 phase wires of the motor
2. adjust the current limiter of the PSU to exactly 1A
3. connect the PSU to the 2 plugs of the motor wire (polarity doesn't matter, and it also doesn't need to be a good connection. You can literaly just take any two wires, put one end in the PSU and rubberband-fix the other one to the phase plug)
4. measure the voltage between the pase wires on a differrent spot on the phase plugs, so that the resistance of the connection between PSU wire and phase plug doesn't influence the reading
5. write down the voltage you measured (should be 10-30 millivolt)

To determine the true phase to phase resistance of the motor, the resistance of the phase wires needs to be subtracted from the measured value. So if you could also write down how long your wires are and what cross section they've got, that'd be awesome.

With the hope of someone actually doing this :D,

Matt