RMS Meter on Servo

I have a 3Phase AC Servo Motor on a CNC that is overheating. Unfortunately I don't have an oscilloscope, but I was trying to take some measurements with my True RMS Meters (Fluke 289 DMM 376 Clamp) Both work very well with inverters as advertised. I have never really dug into the operating signals of an AC Servo, but should I doubt my True RMS Meter any more than on inverter.

Thanks,

Trust Fluke. Inverter is first choice, but both should be close.

With inverters I do trust the Fluke... Never varied more than an amp on a new drive. Although with an older drive, I may question the internal meter. The Tech I spoke to however said that it would not work on a 3 Phase AC Servo. Just wondering what the difference.

The drive measures current by looking at the voltage of a low-Ohm resistor in series with the output.
True-RMS digitizes the entire sine wave, then does the math. The RMS function is typically done with a dedicated IC.
The only difference is the coupling method. After that, calculation method should be the same.