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Update... I noticed the voltage imbalance at our plant had improved the other day, so I checked the current on this drive again. We were pulling current on all three phases, it's still not balanced but it's closer than it was. A few weeks ago the drive was running at: 22Hz. 17amps 672BusVDC...

A few weeks ago I checked the voltages at our MCC Before we fired the plant up. The only load was a 480v 3 phase well pump and a 45 KVA 480v to 208v transformer. I turned off all the lights and the voltages were still about 10v high on one phase. Somewhere around 502,492,492. I’m not sure if the...

Thanks for the info guys; I'm really getting some good insight. At first I suspected the incoming might have been an issue. Upon doing research I discovered NEMA standard MG 1-14.34 which defines voltage unbalance. I also found out a voltage imbalance of 1% can cause a current imbalance of up...

Thanks for the info so far. When I swapped two phases on the input I swapped B & C. C phase had no current before or after swapping the phases. Here is some data I collected yesterday. With the drive running at 22 Hz., 17 amps, & 653 BVDC Input (before line reactor) Voltage Current...

Thats at the panel when most all loads are running. I will get more specific data tomorrow. Is there something specific I need to pay attention to? I've had some concern with power quality. The local utility has a Dranetz power quality analyzer that has been recording all week. It is connected...

Input phase to phase voltages are 468, 468, 478.

I have a 50 horsepower heavy duty drive (AB powerflex 700) connected to a 50 horsepower 1185 RPM, 460V 59.2 FLA motor. It spins a 78.75-inch diameter, 3100-pound cage through a 2.0-1 right angle gearbox. There is also a 250 HP fan pulling air and ground silica through the cage. This airflow...