EM11 User’s Manual
3. Installation of Frequency Inverter
25
3.8.1.4 Main Circuit Terminals Sketch of Model with optional internal braking units
Including model:
Three-phase 220V: EM11-G2-011
～
EM11-G2-037
Three-phase 380V: EM11-G3-018/P3-022
～
EM11-G3-075/P3-090
Terminal symbol
Function description
R/L1
、
S/L2
、
T/L3
Three-phase AC power input terminals
P+
、
P-
DC power input terminals
P+
、
PB
Braking resistor connecting
U/T1
、
V/T2
、
W/T3 Three-phase AC power output terminals
/ E
Grounding terminal
Note:
Product with standard built-in unit can realize DC bus and braking function at the same time, if
external DC reactor and braking function is needed, please contact the manufacturer.
3.9 Cautions for Main Circuit Wiring
3.9.1 Power Supply Wiring
It is forbidden to connect the power cable to the inverter output terminal, otherwise, the internal
components of the inverter will be damaged.
To facilitate the input side over current protection and maintenance after power off, the inverter shall
connect to the power supply through the circuit breaker or leakage circuit breaker and contactor.
Please confirm that the power supply phases, rated voltage are consistent with that of the nameplate,
otherwise, the inverter may be damaged.
3.9.2 Motor Wiring
It is forbidden to short circuit or ground the inverter output terminal, otherwise the internal components
of the inverter will be damaged.
Avoid short circuit the output cables or with the inverter enclosure, otherwise there exists the danger of
electric shock.
It is forbidden to connect the output terminal of the inverter to the capacitor or LC/RC noise filter with
phase lead, otherwise, the internal components of the inverter may be damaged.
When contactor is installed between the inverter and the motor, it is forbidden to switch on/off the
contactor during the running of the inverter, otherwise, there will be large current flowing into the
inverter, triggering the inverter protection action.
Length of cable between the inverter and motor
If the cable between the inverter and the motor is too long, the higher harmonic leakage current of the
output end will produce by adverse impact on the inverter and the peripheral devices. It is suggested that
when the motor cable is longer than 100m, output AC reactor be installed. Refer to the following table
for the carrier frequency setting.
Length of cable between the inverter and motor
Carrier frequency (d6-00)
Less than 50m
Less than 15kHz
Less than 100 m
Less than 10kHz
More than 100m
Less than 5kHz
3. Installation of Frequency Inverter
EM11 User’s Manual
26
3.9.3 Grounding Wiring
The inverter will produce leakage current. The higher the carrier frequency is, the larger the leakage
current will be. The leakage current of the inverter system is more than 3.5mA, and the specific value of
the leakage current is determined by the use conditions. To ensure the safety, the inverter and the motor
must be grounded.
The grounding resistance shall be less than 10ohm. For the grounding wire diameter requirement, refer
to 2.6 electrotype of main circuit peripheral devices.
Do not share grounding wire with the welding machine and other power equipment.
In the applications with more than 2 inverters, keep the grounding wire from forming a loop.
Diagram 3-8 Grounding Wire Connection Sketch Map
3.9.4 Countermeasures for Conduction and Radiation Interference
Diagram 3-9 Connection of conduction and radiation interference solutions
When the input noise filter is installed, the wire connecting the filter to the inverter input power end
shall be as short as possible.
The filter enclosure and mounting cabinet shall be reliably grounded in large area to reduce the back
flow impedance of the noise current Ig.
The wire connecting the inverter and the motor shall be as short as possible. The motor cable adopts
4-core cable, with the grounding end grounded at the inverter side, the other end connected to the motor
enclosure. The motor cable shall be sleeved into the metal tube.
The input power wire and output motor wire shall be kept away from each other as far as possible.
The equipment and signal cables vulnerable to influence shall be kept far away from the inverter.
Key signal cables shall adopt shielding cable. It is suggested that the shielding layer shall be grounded
with 360-degree grounding method and sleeved into the metal tube. The signal cable shall be kept far
away from the inverter input wire and output motor wire. If the signal cable must cross the input wire
and output motor wire, they shall be kept orthogonal.
When analog voltage and current signals are adopted for remote frequency setting, twinning shielding
cable shall be used. The shielding layer shall be connected to the grounding terminal PE of the inverter,
and the signal cable shall be no longer than 50m.
The wires of the control circuit terminals RA/RB/RC and other control circuit terminals shall be
separately routed.
