Mitsubishi Electric FR-E800, Instruction Manual

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11. (H) Protective Function Parameters
11.1 Motor overheat protection (electronic thermal O/L relay)
• Operational characteristic of the electronic thermal relay function
*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)
• 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 .
Protective function activated area: the area right of the characteristic curve
Normal operation area: the area left of the characteristic curve
Range for the
transistor
protection
80 100 120 140 160 200 220 240 260 280 300
Current [%]
* 1
Minute display in
this region
Second display in this region
Thermal relay
operation time [min]
50
60
70
0
60
120
180
240
Thermal relay operation time [s]
2000r/min
2000r/min
RT
SD
MC
MC
W
V
U
M
M