Appendix B. Accessories VFD-EL-W
196
Applications
Connected in input circuit
When more than one AC motor drives are connected to the same mains power and are running, and one
of them is ON during operation.
Issues: When applying power to one of the AC motor drives, the charge current of the capacitors may
cause voltage dip. The AC motor drive may be damaged when over-current occurs during operation.
Correct wiring:
M1
M2
Mn
reactor
AC motor drive
AC motor drive
AC motor drive
motor
motor
motor
A silicon rectifier and AC motor drive are connected to the same power.
Issues: Switching spikes are generated when the silicon rectifier switches ON/OFF. These spikes may
damage the mains circuit.
Correct wiring:
DC
power
reactor
reactor
AC motor drive
motor
Silicon Controlled Rectifier
The power supply capacity is 10 or above times the AC motor drive capacity.
Issues: When the mains power capacity is too large, line impedance is small and the charge current is
too high. This may damage the AC motor drive due to the higher rectifier temperature.
Correct wiring:
large-capacity
power
reactor
small-capacity
AC motor drive
motor