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Chapter 3 Wiring of Inverter
17
3.2 Description of Peripheral Devices for Main Circuit
Circuit breaker
The capacity of the circuit breaker shall be 1.5 ~ 2 time of the rated current of the inverter.
The time features of the circuit breaker shall fully consider the time features of the inverter
overload protection.
Leakage circuit
breaker
Because the inverter output is the high-frequency pulse, there will be high-frequency leakage
current. Special leakage circuit breaker shall be used when installing leakage circuit breaker
at the input end of the inverter.
It is suggested that B type leakage circuit breaker be used, and the leakage current value
shall be set as 300mA.
Contactor
Frequent open and close of contactor will cause inverter failure, so the highest frequency for
the open and close of contactor shall not exceed 10 times/min.
When braking resistor is used, to void the overtemperature damage of the braking resistor,
thermal protection relay with braking resistor overtemperature detection shall be installed to
disconnect the contactor at the contact control power side of the thermal protection relay.
Input AC reactor
or DC reactor
1. The inverter power supply capacity is more than 600kVA or 10 times of the inverter capacity.
2. If there is switch type reactive-load compensation capacitor or load with silicon control at
the same power node, there will be high peak current flowing into input power circuit,
causing the damage of the rectifier components.
3. When the voltage unbalancedness of the three-phase power supply of the inverter
exceeds 3%, the rectifier component will be damaged.
4. It is required that the input power factor of the inverter shall be higher than 90%.
When the above situations occur, install the AC reactor at the input end of the inverter or DC
reactor to the DC reactor terminal.
Input noise filter
The noise input from the power end to the inverter and output from the inverter to the power
end can be reduced.
Thermal protection
relay
Although the inverter has motor overload protection function, when one inverter drives two or
more motors or multi-pole motors, to prevent the motor overtemperature failure, thermal
protection relay shall be installed between the inverter and each motor, and the motor
overload protection parameter P9.16 shall be set as “2” (motor protection disabled).
Output noise filter
When the output end of the inverter is connected with noise filter, the conduction and
radiation interference can be reduced.
Output AC reactor
When the cable connecting the inverter and the motor is longer than 100m, it is suggested to
install AC output reactor to suppress the high-frequency oscillation to avoid the damage to
motor insulation, large leakage current and frequent inverter protective action.
3.3 Lectotype of mMain Circuit Peripheral Devices
Inverter model
Circuit
Breaker
(A)
Contactor
(A)
R/L1, S/L2, T/L3,
⊕
1,
⊕
2/B1, B2,
Ө
, U/T1, V/T2, W/T3
Grounding terminal
PE
Terminal
screw
Tightenin
g torque
(N·m)
Wire
specificatio
n (mm
2
)
Terminal
screw
Tightening
torque
(N·m)
Wire
specification
(mm
2
)
V5
−
H
−2T0.4G
16
10
M4
1.2~1.5
2.5
M4
1.2~1.5
2.5
V5
−
H
−2T0.75G
25
16
M4
1.2~1.5
2.5
M4
1.2~1.5
2.5
V5
−
H
−2T1.5G
32
25
M4
1.2~1.5
4
M4
1.2~1.5
2.5
V5
−
H
−2T2.2G
40
32
M4
1.2~1.5
6
M4
1.2~1.5
4
V5
−
H
−4T0.75G/1.5L
10
10
M4
1.2~1.5
2.5
M4
1.2~1.5
2.5
V5
−
H
−4T1.5G/2.2L
16
10
M4
1.2~1.5
2.5
M4
1.2~1.5
2.5
V5
−
H
−4T2.2G/3.7L
16
10
M4
1.2~1.5
2.5
M4
1.2~1.5
2.5
V5
−
H
−4T3.7G/5.5L
25
16
M4
1.2~1.5
4
M4
1.2~1.5
4
V5
−
H
−4T5.5G/7.5L
32
25
M4
1.2~1.5
6
M4
1.2~1.5
6
V5
−
H
−4T7.5G/11L
40
32
M4
1.2~1.5
6
M4
1.2~1.5
6
