Specifications

Calculating Voltage Unbalance

NEMA MG1 Unbalance Formula

% Voltage Unbalance = Maximum Deviation from the Average

x 100%

Average

Example: The measured line-to-line voltages are 203, 210, and 212.

Average = 203 + 210 + 212

= 208.3

The maximum deviation from the average is the largest difference between the average voltage

(208.3) and any one voltage reading.

208.3 - 203 = 5.3 210 - 208.3 = 1.7 212 - 208.3 = 3.7

The maximum deviation from the average is 5.3.

% voltage unbalance = 5.3

x 100 = 2.5% unbalance

208.3