Mitsubishi Electric 800 Series, Instruction Manual, Page: 66 / 727

Connection of stand-alone option units
INSTALLATION AND WIRING
65
2
2.10
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.
2.10.1
Connection of the brake resistor other than the
provided brake resistor
When an inverter-driven motor is driven by a load or requires rapid deceleration, install a brake resistor. A brake resistor is
provided with the FR-A860-00090 or lower. Fit another brake resistor when the provided brake resistor does not have enough
thermal capability for high-duty operation. For the FR-A860-00027 to 00170, and the FR-A860-00450 to 01080, connect the
brake resistor across terminals P3 and PR. For the FR-A860-00320, connect the brake resistor across terminals P/+ and PR.
(For the locations of terminal P3(P/+) and PR, refer to the terminal block layout (
page 35 ).)
The brake resistor should be as listed in the following table. Selected the rated power of the brake resistor according to the
brake duty. (The rated power indicated below assumes that the brake resistor duty is 10%)

For the FR-A860-00320 or higher, the brake duty is 6%.
Set parameters as below.
•
Pr.30 Regenerative function selection = "1"
• Pr.70 Special regenerative brake duty = "FR-A860-00170 or lower: 10%, FR-A860-00320 or higher: 6%"
(Refer to page 608 .)
• When the regenerative brake transistor is damaged, install a thermal relay as shown in the following sequence diagrams to
prevent overheat and burnout of the brake resistor. Properly select a thermal relay according to the regenerative driving
frequency or the rated power or resistance of the brake resistor.
NOTE
• The brake resistor cannot be used together with a brake unit.
• Do not connect the provided brake resistor when connecting the brake resistor other than the provided brake resistor across
terminals P3(P/+) and PR. Otherwise the inverter may be damaged.
Inverter size Brake resistance Reference rated power at brake duty of 10% (6%)

FR-A860-00027 1000

or more 180 W or more
FR-A860-00061 370

or more 500 W or more
FR-A860-00090 220

or more 800 W or more
FR-A860-00170 110

or more 1600 W or more
FR-A860-00320 60

or more 3600 W or more
FR-A860-00450 40

or more 5500 W or more
FR-A860-00680 24

or more 9000 W or more
FR-A860-01080 16

or more 13500 W or more
CAUTION
 If the resistor selection is incorrect, overcurrent may damage the inverter built-in brake transistor.
Also, the resistor may be burned due to overheat.
 If the selection of the thermal relay is incorrect, the resistor may be burned due to overheat.
R
Brake resistor
Thermal
relay
(OCR)
Inverter
PR
P3
(P/+)
S/L2
T/L3
R/L1
MC
Power
Supply
T
F
ON OFF
MC
MC
OCR
Contact
<Example 1>
MC
Power
Supply
<Example 2>
S/L2
T/L3
R/L1
Inverter
(OCR)
Thermal
relay
B
C
T
F
ON OFF
OCR
Contact
MC
MC
R
Brake resistor
PR
P3
(P/+)