9-3
Name of option
Function and application
DC reactors
(DCRs)
A DCR is mainly used for power supply matching and for input power factor
correction (for reduction of harmonics).
1) For power supply matching
- Use a DCR when the capacity of a power supply transformer exceeds 500
kVA and is 10 times or more than the rated inverter capacity. In this case,
the percentage-reactance of the power supply decreases, and harmonic
components and their peak levels increase. These factors may break
rectifiers or capacitors in the converter section of inverter, or decrease the
capacitance of the capacitor (which can shorten the inverter’s service
life).
- Also use a DCR when there are thyristor-driven loads or when
phase-advancing capacitors are being turned ON/OFF.
2) For input power factor correction (reduction of harmonics)
Generally a capacitor is used to correct the power factor of the load,
however, it cannot be used in a system that includes an inverter. Using a
DCR increases the reactance of inverter’s power supply so as to decrease
harmonic components on the power supply lines and correct the power
factor of inverter. Using a DCR reforms the input power factor to
approximately 90 to 95%.
Note:
At the time of shipping, a jumper bar is connected across the terminals
P1 and P (+) on the terminal block. Remove the short bar when connecting a
DCR.
Output circuit
filters
(OFLs)
Include an OFL in the inverter power output (secondary) circuit to:
1) Suppress the surge voltage at motor terminal
This protects the motor from insulation damage caused by the application of
high surge voltage.
2) Suppress leakage current from the power output lines (due to harmonic
components)
This reduces the leakage current when the motor is hooked by long power
feed lines. It is recommended that the length of the power feed line be kept
to less than 400 m.
3) Minimize emission and/or induction noise issued from the power output
lines
OFLs are effective in reducing noise from long power feed lines, such as
those used in plants, etc.
Note:
Use an output circuit (secondary) filter of OFL-
-
A.
Zero-phase
reactors for
reducing radio
frequency noise
(ACL)
An ACL is used to reduce radio noise emitted by the inverter.
An ACL suppresses the outflow of high frequency noise caused by switching
operation for the power supply (primary) lines inside the inverter. Pass the
power supply lines together through the ACL for 4 turns (coiled 3 times).
Use 4 ACLs and let the power supply lines pass through them when the power
supply lines size are large.
If wiring length between the inverter and motor is less than 20 m, insert an ACL
to the power supply (primary) lines; if it is more than 20 m, insert it to the power
output (secondary) lines of the inverter.
Main opti
on
AC Reactor
(ACR)
•
This optional feature must be connected to the primary side (commercial
power supply side) of the inverter, when the inter-phase unbalance factor of
the commercial power supply is 2% to 3%.
67
×
(V)
voltage
average
phase
-
Three
(V)
voltage
Min.
(V)
voltage
Max.
=
(%)
unbalance
Voltage
In case the inter-phase unbalance factor of the commercial power supply
exceeds 3%, you would need to take other measures such as increasing
the capacity of the inverter. Contact your Fuji Electric representative.
•
In a DC link bus system (using terminals [P (+)] and [N (-)]), the AC reactor
protects the inverter against damage caused by unbalance in current.
Braking resistors
(DBRs)
A braking resistor converts regenerative energy generated from deceleration
of the motor and converts it to heat for consumption. Use of a braking resistor
results in improved deceleration performance of the inverter.
