Mitsubishi Electric FR-A520-0.4K -55K Instruction Manual page 36

( 2 ) Connection of the FR-BU brake unit (option)
Connect the optional FR-BU brake unit as shown below to improve the braking capability during deceleration.
MC
Remove jumper.
Note: 1. Connect the inverter terminals (P, N) 〈+, −〉 and FR-BU brake unit terminals so that their terminal
signals match with each other. (Incorrect connection will damage the inverter.) For model 7.5K or
less, the jumper across terminals PR-PX must be removed.
2. The wiring distance between the inverter, brake unit and resistor unit should be within 5m (16.40
feet). If twisted wires are used, the distance should be within 10m (32.8 feet).
3. 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 a current in
case of failure.
4. For the power supply of 400V class, install a voltage-reducing transformer.
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T (Note 4)
R 〈L 〉
Motor
U
1
S 〈L 〉
V
2 IM
T 〈L 〉
W
3
PR
Inverter
〈+〉 P
PR P/+
〈–〉 N
PX N/-
Brake unit
FR-BU-(H)
25
INSTALLATION AND WIRING
ON
MC
OFF
MC
PR P
HA
TH1
HB
HC
THS TH2
Resistor unit
FR-BR-(H)