C-3
2.3 When it is running continuously
The requirement of load capacity should be less than the capacity of AC motor
drive(kVA)
The requirement of load capacity=
)(_____
cos
kVAdrivemotorACofcapacitythe
Pk M
The motor capacity should be less than the capacity of AC motor drive
)(_____103
3
kVAdrivemotorACofcapacitytheIVk MM
The current should be less than the rated current of AC motor drive(A)
)(______ AdrivemotorACofcurrentratedtheIk M
Symbol explanation
: Motor shaft output for load (kW)
: Motor efficiency (normally, approx. 0.85)
: Motor power factor (normally, approx. 0.75)
: Motor rated current(A), for commercial power
: Correction factor calculated from current distortion factor (1.05-1.1, depending on
PWM method)
: Continuous motor capacity (kVA)
: Starting current/rated current of motor
: Number of motors in parallel
: Number of simultaneously started motors
: Total inertia (GD
2
) calculated back to motor shaft (kg m
2
)
: Motor acceleration time