Appendix C How to Select the Right AC Motor Drive
VFD-EL-W
C-3
Symbol explanation
Motor shaft output for load (kW)
η Motor efficiency (normally approx. 0.85)
Motor power factor (normally approx. 0.75)
Motor rated voltage (V)
Motor rated current (A), for commercial power
Correction factor calculated from the current distortion factor
(1.05–1.1, depending on PWM method)
Continuous motor capacity (kVA)
Starting current/rated current of the motor
Number of motors in parallel
Number of simultaneously started motors
Total inertia (GD
2
) calculated back to motor shaft (kg m
2
)
Load torque
Motor acceleration time
N Motor speed