Mitsubishi Electric FR-A720-0.4K Instruction Manual page 58

Connection of stand-alone option units
(2) Connection with the MT-BU5 (75K or more)
After making sure that the MT-BU5 is properly connected, set the following parameters.
Pr. 30 Regenerative function selection = "1"
Pr. 70 Special regenerative brake duty = "10%" (Refer to page 197)
MCCB
Three-phase
AC power
supply
*1 When the power supply is 400V class, install a step-down transformer.
*2 The wiring length between the resistor unit and brake resistor should be 10m maximum when wires are twisted and 5m
maximum when wires are not twisted.
CAUTION
⋅ Install the brake unit in a place where a cooling air reaches the brake unit heatsink and within a distance of the cable supplied
with the brake unit reaches the inverter.
⋅ For wiring of the brake unit and inverter, use an accessory cable supplied with the brake unit. Connect the main circuit cable to
the inverter terminals P and N and connect the control circuit cable to the CN8 connector inside by making cuts in the rubber
bush at the top of the inverter for leading the cable.
⋅ The brake unit which uses multiple resistor units has terminals equal to the number of resistor units. Connect one resistor unit
to one pair of terminal (P, PR).
<Inserting the CN8 connector>
Make cuts in rubber bush of the upper portion of the inverter and lead a cable.
1) Make cuts in the rubber bush for leading the CN8 connector cable with a nipper or cutter knife.
2) Insert a connector on the MT-BU5 side through a rubber bush to connect to a connector on the inverter side.
CN8 connector
CAUTION
Clamp the CN8 connector cable on the inverter side with a wire clamp securely.
Do not connect the MT-BU5 to a CN8 connector of the FR-A740-55K.
48
MC
R/L1
S/L2
T/L3
Inverter
CN8
Make cuts in
rubber bush
Wire clamp
T
*1
Motor
U
V
IM
W
P/+
P
N/
PR
P
PR
Brake unit
MT-BU5
Rubber bushes
ON OFF CR1 CR2
MC
MC
5m or
*2
less
TH1
P
PR
TH2
TH1
P
PR
TH2
Resistor unit
MT-BR5
Insert the connector until
you hear a click sound.
CR1
CR2