Connection Of Stand-Alone Option Units - Mitsubishi Electric FR-E540 K-EC Series Instruction Manual

2.2.5 Connection of stand-alone option units

The inverter accepts a variety of stand-alone option units as required.
Incorrect connection will cause inverter damage or an accident. Connect and operate
the option unit carefully in accordance with the corresponding option unit manual.
(1) Connection of the dedicated external brake resistor (option)
Connect a brake resistor across terminals + and PR. Connect a dedicated brake
resistor only.
(For the positions of terminals + and PR, refer to the terminal block layout (page 19).)
(2) Connection of the BU brake unit (option)
Connect the BU brake unit correctly
as shown on the right. Incorrect
connection will damage the inverter.
Note: 1. The wiring distance between the inverter, brake unit and discharge resistor
should be within 2m. If twisted wires are used, the distance should be within
5m.
2. If the transistors in the brake unit should fail, the resistor will be extremely
hot, causing a fire. Therefore, install a magnetic contactor on the inverter's
power supply side to shut off current in case of failure.
3. When the power supply is 400V class, install a step-down transformer.
INSTALLATION AND WIRING
+ PR
Brake resistor
NFB MC
Inverter
L
1
L
2
L
3
+
T(Note 3)
P
PC
BU brake unit
Brake unit
HC HB
OFF
29
Motor
U
IM
V
W
Remove jumpers.
Discharge resistor
HA HB HC TB
PR
OCR
OCR
Constant-
voltage
power
+
supply
N
Comparator
ON
MC
MC