Connection Of The Brake Unit (Fr-Bu2) - Mitsubishi Electric FR-A820-00046 Instruction Manual

Connection of stand-alone option units
2.10.2

Connection of the brake unit (FR-BU2)

Connect the brake unit (FR-BU2(H)) as shown below to improve the braking capability during decel-
eration.
Connection example with the GRZG type discharging resistor
Three-phase AC
Fig. 2-63:
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 each. 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.
Brake unit
FR-BU2-1.5K
FR-BU2-3.7K
FR-BU2-7.5K
FR-BU2-15K
FR-BU2-H7.5K
FR-BU2-H15K
FR-BU2-H30K
Tab. 2-47:
NOTES 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).
2 - 92
MCCB
power supply
Connection example with the GRZG type discharging resistor
Discharging resistor
GZG 300W-50Ω (one)
GRZG 200-10Ω (three in series)
GRZG 300-5Ω (four in series)
GRZG 400-2Ω (six in series)
GRZG 200-10Ω (six in series)
GRZG 300-5Ω (eight in series)
GRZG 400-2Ω (twelve in series)
Recommended external thermal relay
T
MC
Motor
U
R/L1
S/L2 V
W
T/L3
Inverter
PR
P/+
PX
N/-
≤ 10 m
Recommended
external thermal relay
TH-N20CXHZ 1.3A
TH-N20CXHZ 3.6A
TH-N20CXHZ 6.6A
TH-N20CXHZ 11A
TH-N20CXHZ 3.6A
TH-N20CXHZ 6.6A
TH-N20CXHZ 11A
Installation and wiring
ON OFF
MC
MC
GRZG type
discharging
OCR resistor
R R
External
thermal
M
relay
FR-BU2
PR
A
P/+
B
N/-
C
BUE
SD
To the brake unit
terminal P/+
OCR
contact
I002408E
To a resistor