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2
Device
Mounting Location
Function Description
Breaker
Between power and AC
drive input side
MCCB: Cuts off power supply when overcurrent occurs on
downstream devices.
Leakage breaker: Provides protection against potential leakage current
during drive operation to prevent electric shock and fire.
Fuse
Between power and AC
drive input side
Provides protection in case of short circuit.
Contactor
Between breaker and AC
drive input side
Switches the AC drive ON/OFF. Do not start/stop the AC drive
frequently by switching contactor ON/OFF (time interval is at least one
hour) nor use to directly start the AC drive.
AC reactor
AC drive input side
Improves the power factor of the drive as seen by the source.
Reduces harmonics on the line side and minimizes voltage distortion.
Reduces input current imbalance due to voltage imbalance.
EMC filter
AC drive input side
Reduces external conduction and radiation interference of the AC drive.
Decreases conduction interference flowing from power supply to the AC
drive and improves the drive’s immunity to the interference.
AC reactor
AC drive input side
Improves the power factor of the drive as seen by the source.
Reduces harmonics on the line side and minimizes voltage distortion.
Reduces input current imbalance due to voltage imbalance.
Braking
resistor
Brake IGBT included in
drives 100 HP (75kW)
and below. Use external
resistor when required.
Dissipates regenerative energy during motor deceleration.
Above 100 HP (75kW), use external brake unit and resistor, when
required.
Braking unit Above 100 HP (75kW) use
external brake unit and
resistor, when required.
Dissipates regenerative energy during motor deceleration.
Output
reactor
Between AC drive output
side and the motor, close
to the AC drive
If the distance between the drive and motor is between 100 ft. and
300 ft., install an AC output reactor.
Physical distance between the AC drive and connected motor causes
distributed capacitance in the circuit and certain harmonics that may
cause resonance in the circuit.
Install an output reactor to:
(a) Minimize degradation of motor insulation.
(b) Reduce leakage current
(c) Minimize drive nuisance trips
dV/dT
reactor
AC drive output side,
close to the AC drive
If the distance between the drive and the motor is greater than 300 ft.
but less than 1500 ft., install a dV/dT (long lead) filter.
(a) Protects motor insulation
(b) Reduces motor bearing currents
Motor
AC drive output side
Select an appropriate motor.
2. SYSTEM CONNECTION
2.2 BENSHAW POWERPRO
™
HIGH PERFORMANCE SINGLE AC DRIVE SYSTEM COMPOSITION
Table 2-2 Description of peripheral electrical devices used with AC drives. See section 5.2.3
and Appendix A for recommended sizing of these peripheral devices and accessories.
Note: Inputs/Outputs (main circuit) of the AC drive contain harmonics, which may interfere
with the communication device connected to the AC drive. Install reactors and/or other
filters to minimize interference.
CAUTION
• Do not install capacitors or surge
suppressors on the output side of the
AC drive. Otherwise, it may damage the
AC drive.or paper is left on the drive,
the drive may have abnormal heating
due to poor ventilation.
