I checked my Uo value and it is 10 volts. Not sure if that is significant, but the original purpose for putting it there was to increase voltage, decrease current. Can't change while its running, so next opportunity I'll change it to zero.
Generally I am learning that there is not much more I...
I know measuring voltage and current on the outlet of a VFD is difficult and requires special equipment, but can you measure (accurately) power factor? Might this help understand whats going on any better?
But this would lower the voltage across the speed range, thereby increasing my current (assuming the same load). Seems that this would take me in the wrong direction (more current). Is there something counter intuitive here?
Yes the VFD is set for 60 Hz operation and 460 V. The compressor sends a start command to the VFD, and before this it moves its unloading valves all the way open. We don't have issues starting the system, just steady state operation.
As I understand it, U0 is the zero frequency voltage used...
Around 60% we start getting really close to FLA * 1.15 (i.e. about 620 amps, motor FLA is 548 amps). In a few instances the VFD/compressor has tripped when it went above 630 amps.
Full VFD part number is ATV61HC31N4. Note that this was packaged by Motortronix, but the only thing they did was...
Thanks all for your comments. First off, this is a case of a the EPC (engineer/procure/construct) firm selecting a VFD other than what the compressor mfr wanted, likely to save money. I have brought in many Schneider folks to deal with this, as well as compressor folks, but each says their...
I've got a 500 Hp Altivar 61 VFD from Schneider electric that is in direct drive with a positive displacement compressor. Schneider Tech support indicates that an Altivar71 is what I should have, but in reality the 61 is indeed what I want since my loading curve is smooth.
Anyway, my problem...
