Omron RX2 Series User Manual page 110

2 Design
 200 V Class Models with 30 kW or Higher/400 V Class Models with 45 kW or
Higher
These models have no built-in regenerative braking circuit.
To improve the braking capacity, use the optional external braking resistor(s) and regenerative brak-
ing unit(s). In this case, connect the terminals (P, N) of the regenerative braking unit to the inverter's
terminals (P, N).
Braking unit
(option)
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 Regen-
erative 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.
• Wiring diagram for connecting one Regenerative Braking Unit (Model: 3G3AX-RBU23)
MCCB
R
S
T
3-phase 200 V
*1. For RY, select the contact rating according to the ratings of the coils MC1 and MC2.
*2. MC1 and MC2 are used not only to provide redundancy, but also to meet safety standards.
2 - 56
Short bar
MC1 MC2
ON
Fuse
Inverter
MC1 *2
MC2
R/L1 U/T1
S/L2 V/T2
T/L3 W/T3
P/+
N/-
RY
OFF
Motor
SL1 SL2 AL1 AL2 RB
P
P
3G3AX-RBU23
N
Master
MA1 MA2
Regenerative braking unit
High-function General-purpose Inverter RX2 Series User's Manual
*1
RY
MC1
MC2
3G3AX-RBA
/RBB/RBC
1(AL1) RB
2(AL2)
P