Mitsubishi Electric FR-A820-00046 Instruction Manual page 121

Installation and wiring
● 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.
Example 1
Power
supply
Fig. 2-62:
Since the FR-A820-00630(11K) or higher and FR-A840-00310(11K) or higher are not provided with
the PX terminal, a jumper needs not to be removed.
CAUTION
E
●
If the resistor selection is incorrect, overcurrent may damage the inverter built-in brake
transistor. Besides, 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.
FR-A800
Inverter
MC
R/L1 P/+
(P3)
S/L2
T/L3
PX
T
PR
F
MC
OFF ON
OCR
contact
MC
Protective circuit
Connection of stand-alone option units
Thermal
relay
Example 2
Brake
(OCR)
resistor
R
Power
supply
F
Disconnect jumper
OFF
Inverter Thermal
relay
(OCR)
MC
R/L1 P/+
(P3)
S/L2
T/L3
PX
T
PR
B
Disconnect jumper
MC
ON
C
OCR
contact
MC
Brake
resistor
R
I002406E, I002407E
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