Mitsubishi Electric 800 Series Instruction Manual (Function page 280

• Operational characteristic of the electronic thermal relay function
70
60
50
240
180
120
60
0
80 100 120 140 160 200 220 240 260 280 300
Protective function activated area: the area right of the characteristic curve
Normal operation area: the area left of the characteristic curve
*1 The % value denotes the percentage to the rated motor current.
NOTE
• The internal accumulated heat value of the electronic thermal relay function is reset to the initial value by the inverter's power
reset or reset signal input. Avoid unnecessary reset and power-OFF.
• When using a PM motor, set the free thermal parameters (Pr.600 to Pr.604) in accordance with the motor characteristic.
• The transistor protection thermal O/L relay is activated early when the Pr.72 PWM frequency selection setting is increased.
 Set two types of electronic thermal O/L relays (Pr.51)
MC
MC
U
V
W
RT
SD
• These settings are used when rotating two motors with different rated current separately by a single inverter. (When
rotating two motors together, use an external thermal relay.)
• Set the rated motor current for the second motor in Pr.51 Second electronic thermal O/L relay.
2000r/min
2000r/min
Range for the
transistor
protection
Current [%]
* 1
M
M
12. (H) Protective Function Parameters
12.1 Motor overheat protection (electronic thermal O/L relay)
11
12
13
14
15
16
17
18
19
20
279