Mitsubishi Electric FR-F800 Series Instruction Manual page 83

2.8.2 Connection of the brake unit (FR-BU)
Connect the brake unit (FR-BU(-H)) as follows to improve the braking capability during deceleration. The FR-BU is compatible
with the FR-F820-02330(55K) or lower and the FR-F840-01160(55K) and lower.
*1 When wiring, make sure to match the terminal symbols (P/+, N/-) on the inverter and on the brake unit (FR-BU(-H)). (Incorrect connection will
damage the inverter.)
*2 When the power supply is 400 V class, install a stepdown transformer.
*3 The wiring distance between the inverter, brake unit (FR-BU) and resistor unit (FR-BR) must be within 5 m. Even when the cable is twisted, the
wiring length must be within 10 m.
*4 A jumper is installed across terminals P/+ and P1. Do not remove the jumper except when connecting a DC reactor (FR-HEL).
NOTE
• If the transistors in the brake unit should become faulty, the resistor will overheat. Install a magnetic contactor on the inverter's
input side and configure a circuit that shut off the current in case of a fault.
2.8.3 Connection of the brake unit (BU type)
Connect the brake unit (BU type) correctly as follows. Incorrect connection will damage the inverter. Remove the jumpers
across terminals HB and PC and terminals TB and HC on the brake unit, and fit one across terminals PC and TB. The BU type
brake unit is compatible with the FR-F820-02330(55K) or lower and the FR-F840-01160(55K) or lower.
Three-phase
AC power
supply
*1 When the power supply is 400 V class, install a stepdown transformer.
*2 A jumper is installed across terminals P/+ and P1. Do not remove the jumper except when connecting a DC reactor (FR-HEL).
NOTE
• The wiring distance between the inverter, brake unit, and discharging resistor must be within 2 m. Even when the cable is
twisted, the wiring length must be within 5 m.
• If the transistors in the brake unit should become faulty, the resistor will overheat and result in a fire. Install a magnetic
contactor on the inverter's input side and configure a circuit that shut off the current in case of a fault.
82
2. INSTALLATION AND WIRING
2.8 Connection of stand-alone option units
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MCCB
Three-phase AC
power supply
MC
MCCB
search engine
T 
MC
Motor
R/L1 U
S/L2 V
T/L3 W
Inverter
P1
P/+ 
N/-
10 m or less
T 
Inverter
Motor
U
R/L1
V M
S/L2
W
T/L3
N/-

P/+
P1
Discharging
resistor
ON OFF
MC
MC
FR-BR
P TH1
M
PR
TH2
FR-BU
PR
HA
P/+
HB

N/- HC

ON OFF
MC
MC
Brake unit
Remove the
(BU type)
jumper
TB
N
HC
OCR
HB
HA
OCR
PC
PR
Fit a jumper
P