Motor Overheat Protection (Electronic Thermal O/L Relay) - Mitsubishi FR-A800 Instruction Manual

5.10.1
Motor overheat protection (electronic thermal
O/L relay)
Set the current of the electronic thermal O/L relay function to protect the motor from overheating. Such settings will
provide the optimum protective characteristic considering the low cooling capability of the motor during low-speed
operation.
Pr. Name
9 Electronic thermal O/L
H000 relay
600 First free thermal reduction
H001 frequency 1
601 First free thermal reduction
H002 ratio 1
602 First free thermal reduction
H003 frequency 2
603 First free thermal reduction
H004 ratio 2
604 First free thermal reduction
H005 frequency 3
607 Motor permissible load
H006 level
51 Second electronic thermal
H010 O/L relay
692 Second free thermal
H011 reduction frequency 1
693 Second free thermal
H012 reduction ratio 1
694 Second free thermal
H013 reduction frequency 2
695 Second free thermal
H014 reduction ratio 2
696 Second free thermal
H015 reduction frequency 3
608 Second motor permissible
H016 load level
561 PTC thermistor protection
H020 level
1016 PTC thermistor protection
H021 detection time

The initial value for the FR-A820-00077(0.75K) or lower and FR-A840-00038(0.75K) or lower is set to the 85% of the rated inverter current.

The setting range for FR-A820-03160(55K) or lower and FR-A840-01800(55K) or lower. The minimum setting increment is "0.01 A".

The setting range for FR-A820-03800(75K) or higher, and FR-A840-02160(75K) or higher. The minimum setting increment is "0.1 A".
Setting
Initial value
range
0 to 500 A
Rated inverter 
current

0 to 3600 A

0 to 590 Hz
9999
9999
1 to 100%
100%
9999
0 to 590 Hz
9999
9999
1 to 100%
100%
9999
0 to 590 Hz
9999
9999
150% 110 to 250%
0 to 500 A

9999 0 to 3600 A

9999
0 to 590 Hz
9999
9999
1 to 100%
100%
9999
0 to 590 Hz
9999
9999
1 to 100%
100%
9999
0 to 590 Hz
9999
9999
110 to 250%
9999
9999
0.5 to 30 kΩ
9999
9999
0 s 0 to 60 s
(H) Protective function parameter
Description
Set the rated motor current.
The electronic thermal O/L relay operation level can be
changed to match the motor temperature
characteristics with the combination of these three
points (Pr.600, Pr.601), (Pr.602, Pr.603), (Pr.604, Pr.9).
9999: Free thermal O/L relay invalid
Set the permissible load according to the motor
characteristics.
Enabled when the RT signal is ON.
Set the rated motor current.
Second electronic thermal O/L relay invalid
The electronic thermal O/L relay operation level can be
changed to match the second motor temperature
characteristics with the combination of these three
points (Pr.692, Pr.693), (Pr.694, Pr.695), (Pr.696,
Pr.51).
9999: Second free thermal O/L relay invalid
Set the permissible load when the RT signal is ON.
The Pr.607 setting is applied even when the RT signal
is ON.
Set the PTC thermistor protection level (resistance).
PTC thermistor protection disabled
Set the time from when the resistance of the PTC
thermistor reaches the protection level until the
protective function is activated.
PARAMETERS
5
GROUP
H
331