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...
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...