Delta Electronics VFD-EL series

Revision 2016/03, 6ELE, V1.14
B-8
B.4.3 Applications
Connected in input circuit
Application 1
Question
When more than one AC motor drive is connected
to the same mains power, and one of them is ON
during operation.
When applying power to one of the AC motor drive,
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
Application 2 Question
Silicon rectifier and AC motor
drive are connected to the same
power.
Switching spikes will be
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
Application 3 Question
Used to improve the input power factor, to reduce
harmonics and provide protection from AC line
disturbances. (surges, switching spikes, short
interruptions, etc.). The AC line reactor should be
installed when the power supply capacity is 500kVA
or more and exceeds 6 times the inverter capacity,
or the mains wiring distance
≤
10m.
When the mains power capacity is too large, line
impedance will be small and the charge current will
be too high. This may damage AC motor drive due to
higher rectifier temperature.
Correct wiring
large-capacity
power
reactor
small-capacity
AC motor drive
motor