Connection Of The Brake Unit (Fr-Bu2) - Mitsubishi Electric FR-A720-0.4K Instruction Manual

2.5.2

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 brake resitor
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 Be sure to remove a jumper across terminal PR-PX when using the FR-BU2 with the inverter of 7.5K or less.
*4 Keep a wiring distance of within 5m between the inverter, brake unit (FR-BU2) and brake resistor. Even when the wiring is
twisted, the cable length must not exceed 10m.
*5 It is recommended to install an external thermal relay to prevent overheat of brake resistors.
<Recommended external thermal relay>
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
CAUTION
⋅ To replace the existing BU type brake unit, set "1" in Pr. 0 Brake mode selection of the FR-BU2.
⋅ Do not remove a jumper across terminal P/+ and P1 except when connecting a DC reactor.
T
MCCB MC
R/L1
S/L2
T/L3
Inverter
PR
*3
PX
Brake Resistor
GZG 300W-50Ω
GRZG 200-10Ω
GRZG 300-5Ω
GRZG 400-2Ω
GRZG 200-10Ω
GRZG 300-5Ω
GRZG 400-2Ω
Connection of stand-alone option units
*2
MC
GRZG type
brake resistor
R
Motor
U
V
IM
W
FR-BU2
*4
PR
P/+
P/+
*1
N/-
N/-
BUE
SD
*4
5m (16.4feet) or less
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
ON OFF
MC
R
A
B
C
45
2