IMO Jaguar CUB, Instruction Manual

Page: 42 / 170

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2.3.11 Cautions Relating to Harmonic Component, Noise, and Leakage Current
(1) Harmonic component
Input current to an inverter includes a harmonic component, which may affect other loads and
condensive capacitors that are connected to the same power source as the inverter. If the harmonic
component causes any problems, connect a DC reactor (option) to the inverter. It may also be
necessary to connect an AC reactor to the condensive capacitors.
(2) Noise
If noise generated from the inverter affects other devices, or that generated from peripheral equip-
ment causes the inverter to malfunction, follow the basic measures outlined below.
1) If noise generated from the inverter affects the other devices through power wires or grounding
wires:
- Isolate the grounded metal frames of the inverter from those of the other devices.
- Connect a filter to the inverter power wires.
- Isolate the power system of the other devices from that of the inverter with an EMC isolating
transformer.
2) If induction or radio noise generated from the inverter affects other devices through power wires
or grounding wires:
- Isolate the main circuit wires from the control circuit wires and other device wires.
- Put the main circuit wires through a metal conduit and connect the pipe to the ground near the
inverter.
- Mount the inverter onto a metal board and connect the whole board to the ground.
- Connect an EMC filter to the inverter power wires.
3) When implementing measures against noise generated from peripheral equipment:
- For the control circuit wires, use twisted or shielded-twisted wires. If using shielded-twisted
wires, connect the shield of the shielded wires to the common terminals of the control circuit.
- Connect a surge absorber in parallel with a coil or solenoid of the magnetic contactor.
(3) Leakage current
Harmonic component current generated by transistors (IGBTs) switching on/off in the inverter forces
leakage current through stray capacitors of inverter input and output wires or a motor. If any of the
problems listed below occur, take appropriate measures against them.
Table 2.9 Leakage Current Countermeasures
Problem Measures
An earth leakage circuit
breaker* that is connected
to the power supply has
isolated the inverter from the
power supply.
* With the exception of those
exclusively designed for pro-
tection from ground faults
1) Decrease the carrier frequency.
2) Make the wires between the inverter and motor shorter.
3) Use an earth leakage circuit breaker that has a larger cur-
rent sensitivity than one currently being used.
4) Use an earth leakage circuit breaker that features measures
against harmonic component.
An external thermal relay
was activated. 1) Decrease the carrier frequency.
2) Increase thermal time constant.
3) Use the thermal relay built in the inverter.