Omron VARISPEED L7 Manual page 45

Wiring the Output Side of the Main Circuit
The following precautions should be considered for the output circuit wiring.
Connecting the Inverter and Motor
The output terminals U/T1, V/T2 and W/T3 must be connected according to the motor lead wires U, V and W.
The motor should rotate forward with the forward run command. If not, two of the motor cable wires can be
switched.
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Never Connect a Power Supply to Output Terminals
A power supply must never be connected to the output terminals U/T1, V/T2, and W/T3. Otherwise the inter-
nal circuits of the Inverter will be damaged.
Never Short or Ground Output Terminals
If the output terminals are touched with bare hands or the output wires come into contact with the Inverter
case, an electric shock or a short circuit may occur.
Do Not Use a Phase Advancing Capacitor
A phase advancing capacitor must never be connected to the inverter output circuit. The high-frequency com-
ponents of the Inverter output may overheat and be damaged and may cause other parts to burn.
Using a Magnetic Contactor
A magnetic contactor (MC) between the Inverter and motor must not be turned ON or OFF during inverter
operation. If the MC is turned ON during the Inverter is operation, a large inrush current will be created and
the inverter's over current protection may operate.
Ground Wiring
The following precautions should be considered for the ground connection.
Always use the ground terminal of the 200 V Inverter with a ground resistance of less than 100 Ω and that
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of the 400 V Inverter with a ground resistance of less than 10 Ω.
Ground wires should not be shared with other devices, such as welding machines or power tools.
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A ground wire, that complies with technical standards on electrical equipment must be used. The length of
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the ground wire should be as low as possible.
Leakage current flows through the Inverter. Therefore, if the distance between the ground electrode and the
ground terminal is too long, potential on the ground terminal of the Inverter will become unstable.
When more than one Inverter is used the ground wires should not be looped.
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OK
Fig 2.6 Ground Wiring
NO