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INSTALLATION AND WIRING
8
2.2.2 Wiring of the main circuit
(
1
)
Wiring instructions
1) Power must not be applied to the output terminals (U, V, W) of the inverter. Otherwise the inverter will be
damaged.
2) After wiring, wire off-cuts must not be left in the inverter.
Wire off-cuts can cause an alarm, failure or malfunction. Always keep the inverter clean.
3) Use thick cables to make a voltage drop of 2% or less.
If the wiring distance is long between the inverter and motor, a main circuit cable voltage drop will cause the
motor torque to decrease especially at the output of a low frequency.
4) Electromagnetic wave interference
The input/output (main circuit) of the inverter includes harmonic components, which may interfere with the
communication devices (such as AM radios) used near the inverter. In this case, use shielded wire cables
as the power cable.
5) Do not install a power capacitor, surge suppressor or radio noise filter (FR-BIF option) in the output side of
the inverter.
This will cause the inverter to trip or the capacitor and surge suppressor to be damaged. If any of the above
devices are installed, immediately remove them.
6) When rewiring after operation, make sure that the POWER lamp has gone off, and when more than
10minutes have elapsed after power-off, check with a tester that the DC bus voltage is zero. After that, start
rewiring work. For some time after power-off, there is a dangerous voltage in the capacitor.
7) Top attachments should be removed before operating because of Air exhaust. Side attachments can be
used for fixing the unit. (See page 44)
Notes on Grounding
• Leakage currents flow in the inverter. To prevent an electric shock, the inverter and motor must be
grounded (grounding resistance: 10Ω or less.)
• Use the dedicated ground terminal to ground the inverter. (Do not use the screw in the case, chassis, etc.)
• The ground cable should have a thickness of 38mm
2
, or more, and be as short as possible. The grounding
point should be as close to the inverter as possible.