2-12
Chap. 2 MOUNTING AND WIRING THE INVERTER
Primary grounding terminal ( G) for inverter enclosure
Two grounding terminals (
G) are not exclusive to the power supply wiring (primary circuit) or motor wiring (secondary
circuit). Be sure to ground either of the two grounding terminals for safety and noise reduction. The inverter is designed for
use with safety grounding to avoid electric shock, fire and other disasters.
The grounding terminal for inverter enclosure should be grounded as follows:
1) Ground the inverter in compliance with the national or local electric code.
2) Use a thick grounding wire with a large surface area and keep the wiring length as short as possible.
An EMC filter built-in type of inverters with a capacity of 5.5 to 11 kW (both 200 V and 400 V class series) has
three grounding terminals. For effective noise suppression, connect grounding wires to the specified grounding
terminals. (Refer to Chapter 9, Section 9.3.2 "Recommended installation procedure.")
Inverter output terminals U, V, and W and secondary grounding terminals ( G) for motor
Inverter’s output terminals should be connected as follows:
1) Connect the three wires of the 3-phase motor to terminals U, V, and W, aligning the phases each other.
2) Connect the secondary grounding wire to the grounding terminal (
G).
When there is more than one combination of an inverter and motor, do not use a multicore cable for the purpose o
handling their wirings together.
DC reactor terminals P1 and P(+)
Connect a DC reactor (DCR) to these terminals for power factor correction.
1) Remove the jumper bar from terminals P1 and P(+).
2) Connect an optional DCR to those terminals.
• The wiring length should be 10 m or below.
• Do not remove the jumper bar when a DCR is not used.
• Inverters with a capacity of 55 kW in LD mode and inverters with 75 kW or above require a DCR to be
connected. Be sure to connect it to those inverters.
• If a PWM converter is connected to the inverter, no DCR is required.
Be sure to connect an optional DC reactor (DCR) when the capacity of the power supply transformer exceeds 500 kVA
and is 10 times or more the inverter rated capacity.
Otherwise, a fire could occur.
DC braking resistor terminals P(+) and DB (for inverters with a capacity of 22 kW or below)
Capacity (kW) Braking transistor
Built-in DC braking
resistor (DBR)
Optional devices
Option mounting
steps required
0.4 to 7.5 Built-in Built-in
External DC braking resistor
(with a larger capacity)
1), 2), 3)
11 to 22 Built-in None External DC braking resistor 2), 3)
In inverters with a capacity of 7.5 kW or below, if the capacity of the built-in DC braking resistor (DBR) is insufficient since
the inverter undergoes frequent start/stop or heavy inertial load, mount an optional external DC braking resistor (DBR) with a
larger capacity to increase the braking capability, using the following steps. Before mounting the external DBR, remove the
built-in DBR.
1) For inverters with a capacity of 0.4 to 3.7 kW, disconnect the wiring of the built-in DBR from terminals P(+) and DB; for
inverters with a capacity of 5.5 and 7.5 kW, disconnect the wiring from terminal DB and the internal relay terminal (see
the figure below).
Insulate the terminals of the disconnected wires with insulating tape or other materials.
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