Emc Question And Solution - Veikong VFD500 Series Operation Manual

VFD500 high performance vector control frequency inverter user manual
3.3EMCquestion and solution
The working principle of the inverter determines that it will certainly produce electromagnetic interference,
affecting and interfering with other equipment. In the meantime, the frequency converter usually works under the
industrial environment with very strong noise,its internal weak signal is also easily disturbed. For safe and
trouble-free operation of the frequency converter, as well as the normal and orderly operation of other equipment,
install the equipment according to the following rules.。

Install the input noise filter,the filter to the inverter input power supply side of the wiring should be as short
as possible.

Filter shell and the installation of the cabinet should be a large area of reliable connection, in order to
reduce the noise current loop impedance.

The wiring distance between inverter and motor should be as short as possible. The motor cable adopts
4-core cable. One end of the ground wire is grounded at the inverter side and the other end is connected
with the motor case. The motor cable is sheathed into the metal pipe.

Input power line and output motor line should be far away from each other.

Easily affected equipment and signal lines should be installed away from the inverter.

The key signal cable should use shielded cable. It is suggested that the shielded cable layer should be
grounded by 360 degree grounding method and set in the metal pipe. As far as possible from the inverter
input power cable and output motor cable, if the signal cable must cross the input power cable or output
motor cable, the two should be orthogonal.

When using the analog voltage and current signals for remote frequency setting, double-stranded,
shielded and shielded cables should be used, and the shield should be connected to the grounding
terminal PE of the inverter. The longest signal cable should not exceed 50 meters.

The control circuit terminals T1A / T1B / T1C, T2A / T2B / T2C and other control circuit terminals should be
separated wiring.

It is forbidden to short-circuit the shield with other signal lines and equipment.

When connecting the inductive load device (magnetic contactor, relay, solenoid valve, etc.) to the inverter,
be sure to use the surge suppressor on the load device coil.

Correct and reliable grounding is safe and reliable operation of the foundation:
(1) Inverter will generate leakage current, the greater the carrier frequency, the greater the leakage current.
Inverter leakage current greater than 3.5mA, the size of the leakage current by the conditions of use, in order to
ensure safety, inverter and motor must be grounded;
(2) Grounding resistance should be less than 10 ohms. Grounding cable diameter requirement, refer to the
same type of input and output cables half of the cross-sectional area selection;
(3) Do not share the ground wire with welding machines and other power equipment;
(4) When using more than two inverters, do not make the ground wire loop.。
Inverter1
 Frequency converter to motor cable length and carrier frequency to maintain the appropriate
relationship
When the cable between the inverter and the motor is long, due to the influence of distributed capacitance, it is easy
to produce electrical resonance, thus generating a large current so that the inverter over-current protection. It is
Invert1
inverter2 inverter3
Correctincorrect
3-6Ground wire connection diagram
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Chapter3 Product appearance and wiring
Inverter2 inverter3