Omron RX Series - Page 95

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2 Design
High-function General-purpose Inverter 3G3RX-V1 User’s Manual (I578-E1)
2-3 Wiring
2
2-3-4 Wiring for Main Circuit Terminals
When driving a load with a large inertia or a vertical axis, regenerated energy is fed back to the inverter
when it is decelerating or generating downward movement.
If the amount of regenerative energy exceeds the amount allowable for the inverter, an overvoltage is
detected. Use braking resistors or regenerative braking units to prevent this.
 200/400-V class models with 22 kW or lower capacity
The models have a built-in regenerative braking circuit.
To improve the braking capacity, connect the optional external braking resistor to these terminals
(P/+2, RB).
Precautions for Safe Use
• Be sure to install a circuit that detects overheating of the braking resistor via alarm contacts
(thermal relay output terminals) and shuts off the input power supply of the inverter.
• Do not connect a resistor whose resistance is lower than the minimum connection resistance
value specified in the standard specifications table. Doing so may result in damage to the
regenerative braking circuit.
• When using the Braking Resistor (Model: 3G3AX-RBA/RBB/RBC) with a 400-V class inverter,
be sure to connect two braking resistors of the same model in series. Using the inverter with
only one braking resistor connected may cause damage to the braking resistor.
• Wiring diagram
 200/400-V class models with 30 kW or higher capacity
These models have no built-in regenerative braking circuit.
To improve the braking capacity, use the optional external braking resistor(s) and regenerative
braking unit(s). In this case, connect the terminals (P, N) of the regenerative braking unit to the
inverter’s terminals (P/+2, N/–).
Precautions for Safe Use
• Be sure to install a circuit that detects overheating of the regenerative braking unit(s) and
braking resistor(s) via alarm contacts (thermal relay output terminals) and shuts off the input
power supply of the inverter.
• Do not connect a resistor whose resistance is lower than the connection resistance value
specified in the specifications table for that regenerative braking unit. Doing so may result in
damage to the regenerative braking unit.
• When using the Braking Resistor (Model: 3G3AX-RBA/RBB/RBC) with a 400-V class
Regenerative Braking Unit (Model: 3G3AX-RBU41/RBU42/RBU43), be sure to connect two
braking resistors of the same model in series. Using the Regenerative Braking Unit with only
one braking resistor connected may cause damage to the braking resistor.
• When using the Regenerative Braking Unit (Model: 3G3AX-RBU21/RBU22/RBU41) with a
built-in braking resistor with the Braking Resistor (Model: 3G3AX-RBA/RBB/RBC), remove the
built-in resistor according to the manual for the regenerative braking unit. Using the
Regenerative Braking Unit with the built-in resistor connected may cause burnout of the built-in
resistor.
External Braking Resistor Connection Terminal (P/+2, RB)/
Regenerative Braking Unit Connection Terminal (P/+2, N/–)
+1 P/+2
Braking resistors
RBN/–