Series 600 Power Meter
Series 800 Power Meter
Series 2000 Circuit Monitor
Series 3000 Circuit Monitor
Series 4000Circuit Monitor
No, it is not possible to have negative Voltage Unbalance reading from a Series 800 Power Meter or a Series 3000/4000 Circuit Monitor. All voltage unbalance readings will be an absolute value expressed as a percentage of unbalance. Voltage Unbalance is calculated using the following formula: Vunbalance = [(Vavg-Vphase) divided by Vavg].
It is possible, however, to have negative Voltage Unbalance readings if the device is a Series 600 Power Meter or a Series 2000 Circuit Monitor. These devices express Voltage Unbalance as a positive or negative percentage.
In general the absoute value of any Voltage Unbalance larger than 2.5 can cause heating in motors.