Mitsubishi FR-A800

Connection of stand-alone option units
INSTALLATION AND WIRING
73
2
2.9.2 Connection of the brake unit (FR-BU2)
Connect the brake unit (FR-BU2(H)) as shown below to improve the braking capability during deceleration.
Connection example with the GRZG type discharging resistor
NOTE
• Set "1" in Pr.0 Brake mode selection of the FR-BU2 to use a GRZG type discharging resistor.
• Do not remove the jumper across terminals P/+ and P1 except when connecting a DC reactor (FR-HEL).
 When wiring, make sure to match the terminal symbol (P/+, N/-) at the inverter side and at the brake unit (FR-BU2) side.
(Incorrect connection will damage the inverter and brake unit.)
 When the power supply is 400 V class, install a stepdown transformer.
 Be sure to remove the jumper across terminals PR and PX when using the FR-BU2 with the inverter of FR-A820-
00490(7.5K) or lower, FR-A840-00250(7.5K) or lower.
 The wiring distance between the inverter and brake unit (FR-BU2), and between the brake unit (FR-BU2) and
discharging resistor must be within 5 m. Even when the wires are twisted, the cable length must be within 10 m.
 It is recommended to install an external thermal relay to prevent overheat of the discharging resistor.
 For the connection method of the discharging resistor, refer to the Instruction Manual of the FR-BU2.
• Recommended external thermal relay
∗5
∗1
∗4
∗6
U
V
W
P/+
N/-
R/L1
S/L2
T/L3
Motor
M
Inverter
PR
N/-
BUE
SD
P/+
A
B
C
FR-BU2
GRZG type
discharging
resistor
RR
Three-phase AC
power supply
MCCB
MC
OFFON
MC
T
10 m or less
OCR
contact
MC
External thermal
relay
OCR
∗2
∗1
PR
PX
∗3
∗4
Brake unit Discharging resistor
Recommended
external thermal relay
FR-BU2-1.5K GZG 300W-50 (one) TH-N20CXHZ 1.3A
FR-BU2-3.7K
GRZG 200-10
(three in series)
TH-N20CXHZ 3.6A
FR-BU2-7.5K
GRZG 300-5
(four in series)
TH-N20CXHZ 6.6A
FR-BU2-15K
GRZG 400-2
(six in series)
TH-N20CXHZ 11A
FR-BU2-H7.5K
GRZG 200-10
(six in series)
TH-N20CXHZ 3.6A
FR-BU2-H15K
GRZG 300-5
(eight in series)
TH-N20CXHZ 6.6A
FR-BU2-H30K
GRZG 400-2
(twelve in series)
TH-N20CXHZ 11A
To the brake
unit terminal P/+
To a resisto
r
TH-N20
1/L 1 5/L 3
2/T 1 6/T 3