Omron RX User Manual page 38

2-2 Wiring
• In the following cases, the internal converter module may be damaged. Use caution to avoid
them:
Imbalance of power supply voltage is 3% or more.
Power supply capacity is ten times or more than the Inverter capacity, and also 500 kVA or more.
Rapid change in power supply voltage.
2
Example) When several Inverters are connected with a short bus.
• Do not turn power on/off more than once every 3 minutes.
Doing so may damage the Inverter.
Inverter Output Terminals (U/T1, V/T2, W/T3)
• For connection of the output terminal, use the applicable cable or a cable with a larger diameter.
Otherwise, the output voltage between the Inverter and the motor may drop.
Particularly during low-frequency output, a voltage drop occurs with the cable, resulting in motor
torque reduction.
• Do not mount a phase advance capacitor or surge absorber. These devices cause the Inverter to
trip, or may cause damage to the capacitor or surge absorber.
• If the cable length exceeds 20 m (particularly, with 400-V class), a surge voltage may be
generated at the motor terminal due to stray capacitance or inductance of the cable, causing the
motor to burn out.
• To connect several motors, provide a thermal relay for each.
• The RC value of each thermal relay should be 1.1 times of the motor rated current. The relay may
trip easily depending on the cable length. In this case, connect an AC reactor to the Inverter
output.
DC Reactor Connection Terminal (PD/+1, P/+)
• This terminal is used to connect the optional DC reactor for power factor improvement.
By factory default, a short-circuit bar has been connected between the terminals PD/+1 and P/+.
Before connecting the DC reactor, remove this short-circuit bar.
• The length of the DC reactor connection cable should be 5 m or less.
If the DC reactor is not used, do not remove the short-circuit bar.
If you remove the short-circuit bar without connecting the DC reactor, no power is supplied to
the Inverter main circuit, disabling operation.
External Braking Resistor Connection Terminal (P/+, RB)/Regenerative Braking
Unit Connection Terminal (P/+, N/-)
• The Inverters with 22 kW or lower capacity incorporate a regenerative braking circuit.
To improve braking capability, mount the optional external braking resistor to this terminal.
Do not mount a resistor whose resistance is lower than the specified value. Doing so may damage
the regenerative braking circuit.
• The Inverters with 30 kW or higher capacity do not incorporate a regenerative braking circuit.
To improve braking capability, the optional regenerative braking unit and braking resistor are
required. In this case, connect the regenerative braking unit terminals (+, -) to the Inverter
terminals (P/+, N/-).
• The cable length should be 5 m or less. Twist the two wires.
• Do not connect any device other than the optional regenerative braking unit or external braking
resistor to this terminal.
2-13
When the phase advance capacitor is turned on/off.