Connection Of Stand-Alone Option Units; Connection Of The Brake Unit (Fr-Bu2) - Mitsubishi Electric FR-F740-00023 Instruction Manual

2.4 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 accident. Connect and operate the option unit carefully in
accordance with the corresponding option unit manual.
2.4.1

Connection of the brake unit (FR-BU2)

Connect the brake unit (FR-BU2) as shown below to improve the braking capability at deceleration.
(1) Connection example with the GRZG type discharging resistor
Three-phase AC
power supply
*1 Connect the inverter terminals (P/+, N/-) and brake unit (FR-BU2) terminals so that their terminal names match with each other.
(Incorrect connection will damage the inverter and brake unit.)
*2 When the power supply is 400V class, install a step-down transformer.
*3 Keep a wiring distance of within 5m between the inverter, brake unit (FR-BU2) and discharging resistor. Even when the wiring
is twisted, the cable length must not exceed 10m.
*4 It is recommended to install an external thermal relay to prevent overheat of discharging resistors.
*5
Refer to FR-BU2 manual for connection method of discharging resistor.
<Recommended external thermal relay>
Brake Unit Discharging Resistor
GRZG 200-10
FR-BU2-H7.5K
GRZG 300-5
FR-BU2-H15K
GRZG 400-2
FR-BU2-H30K
CAUTION
Set "1" in Pr. 0 Brake mode selection of the FR-BU2 to use GRZG type discharging resistor.
Do not remove a jumper across terminal P/+ and P1 except when connecting a DC reactor.
T
MC
MCCB
R/L1
S/L2
T/L3
Inverter
Recommended External Thermal Relay
(six in series)
(eight in series)
(twelve in series)

Connection of stand-alone option units

*2
GRZG type
discharging resistor
OCR
MC
R
External thermal
Motor
U
relay
*4
V
IM
W
FR-BU2
*3
PR
P/+
P/+
*1
N/-
N/-
BUE
PC
*3
5m or less
TH-N20CXHZ 3.6A
TH-N20CXHZ 6.6A
TH-N20CXHZ 11A
ON OFF OCR contact
MC
R
A
B
C
1/L 5/L
1 3
TH-N20
2/T 6/T
1 3
To a resistor
To the brake
unit terminal P/+
2
31