Wiring Of The Main Circuit - Hitachi SJ700D-004L Instruction Manual

Chapter 2

2.2.2 Wiring of the main circuit

(1) Wiring instructions
Before wiring, be sure to confirm that the Charge lamp on the inverter is turned off. When the inverter power has
been turned on once, a dangerous high voltage remains in the internal capacitors for some time after power-off,
regardless of whether the inverter has been operated. When rewiring after power-off, always wait 10 minutes or
more after power-off, and check with a multimeter that the residual voltage across terminals P and N is zero to
ensure safety during rewiring work.
(note) As for the 5.5kW and 7.5kW inverters, the washer on the main terminal screw (R, S, T, PD, P, N, U, V, W, RB)
has two cutouts. Since those cutouts are to avoid the cable fixing portion of crimp terminal goes under the
washer, it should be fixed in direction with those two cutouts in line with cable as described below.
Otherwise, you run the risk of loose connection and fire.
washer of the terminal screw
1) Main power input terminals (R, S, and T)
- Install an earth-leakage breaker for circuit (wiring) protection between the power supply and main power input
terminals (R, S, and T).
- Use an earth-leakage breaker with a high rating of a high-frequency sensitive current to prevent the breaker
from malfunctioning under the influence of high frequency.
- When the protective function of the inverter operates, a fault or accident may have occurred in your system.
Therefore, you are recommended to connect a magnetic contactor that interrupts the power supply to the
inverter.
- Do not use the magnetic contactor connected to the power input terminal (primary side) or power output
terminal (secondary side) of the inverter to start or stop the inverter. To start and stop inverter operation by
external signals, use only the operation commands (FW and RV signals) that are input via control circuit
terminals.
- This inverter does not support a single-phase input but supports only a three-phase input.
If you need to use a single-phase power input, contact your supplier or local Hitachi Distributor.
- Do not operate the inverter when an input phase is lost (input phase loss), otherwise the inverter may be
damaged. Since the factory setting of the inverter disables the phase loss input protection, the inverter will go
into the following status if a phase of power supply input is interrupted and not supplied to the inverter:
 R or T phase interrupted: The inverter does not power up.
 S phase interrupted: The inverter goes into single-phase operation, and may trip because of insufficient
voltage or overcurrent, or be damaged.
Internal capacitors remain charged, even when the power input is under a phase loss condition. Therefore,
touching an internal part may result in electric shock and injury.
When rewiring the main circuit, follow the instructions given in Item (1), "Wiring instructions."
- Carefully note that the internal converter module of the inverter may be damaged if:
- The imbalance of power voltage is 3% or more,
- The power supply capacity is at least 10 times as high as the inverter capacity and 500 kVA or more, or
- The power voltage changes rapidly.
Example: The above conditions may occur when multiple inverters are connected to each other by a short bus
line or your system includes a phase-advanced capacitor that is turned on and off during operation.
- Do not turn the inverter power on and off more often than once every 3 minutes. Otherwise, the inverter may
be damaged.
2-11
Installation and Wiring