I'm working with a Golden Motor HPM48-5000 (48 volt, 5 kW). It's an axial-flux design with 8 magnets and 24 coils. It weighs 11 kg. I'm trying to reconcile winding resistance and inductance from several sources:
The manufacturer specifies the 48-volt version as having a phase resistance of 6.2 milliohms and a phase inductance of 68 uH @100 kHz. They don't state the conditions under which the measurements were taken. Are these numbers measured at ambient conditions or at operating temperature* and operating current** ? Are those values with or without external factory-provided interconnect leads? Is the motor wired as a wye or a delta?
I measured the motor parameters using a laboratory-grade Wayne Kerr 3245 Precision Inductance Analyzer. At 17* C, with no bias current, I got 7.2 milliohms and 34 uH @ 100 kHz. Actually, I measured 31uH, 34uH, 34uH... repeating like that every 3 "cogs" of rotation for all 24 rotor positions per revolution. I'm wondering if this is expressed by the VESC Tool parameter "Motor Inductance Difference (Ld – Lq)" under the "FOC Advanced" tab? My motor leads are ~6.5mm OD (including insulation) about 33 cm long. I'm guessing they are #4 AWG. That's 91 milliohms per meter, so let's say 0.6 milliohm for the two cables together.
VESC Tool 3.0 says: 131.7 amps, resistance 4.32 milliohms, inductance 11.06 microhenrys, flux linkage 15.02 mWb. Was the inductance determined using 131 A of bias current?
*Since copper has a positive temperature coefficient, the hotter the winding, the higher the resistance.
**Similarly, inductance decreases with increasing bias current.