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Electrical Motor Voltage Imbalance

Reference data and engineering information about electrical motor voltage imbalance for electrical applications.

electricalmotorvoltageimbalance

Overview

Engineering reference data for Electrical Motor Voltage Imbalance in electrical engineering.

Key Formulas

Ohm's Law

V=IRV = IR

Voltage = Current × Resistance.

Power

P=VI=I2R=V2/RP = VI = I^2R = V^2/R

Electrical power.

Energy

E=PtE = Pt

Energy = Power × Time.

Variables

SymbolDescriptionUnit
VVVoltageV
IICurrentA
RRResistanceΩ
PPPowerW

Operating Limits

Electrical motors are designed to operate with high efficiency within specified variation limits:

ParameterLimit
Voltage variation±10%
Frequency variation±5%
Combined voltage and frequency variation (arithmetic sum)10%
Voltage imbalance between phases1%

Voltage Imbalance Derating

When voltage imbalance exceeds 1%, motors must be derated to prevent overheating. The derating factor is applied to the motor's rated capacity.

10 rows
Polyphase Motor Voltage Imbalance Derating Factors
Voltage Imbalance(%)
Derating Factor
01
0.51
1.50.97
20.95
2.50.93
30.89
3.50.85
40.82
4.50.78
50.76

Source: engineeringtoolbox.com

Interactive Charts

Polyphase Motor Voltage Imbalance Derating Factors

References