• When using the Mitsubishi Electric constant-torque motor, set "1" in
constant-torque characteristic in the low-speed range.)
Pr. 9 = 50% setting
of inverter rating*
Inverter output power (%)
(% to the inverter rated current)
When setting Pr.9 to a value (current value) of 50% of the inverter rated current
The % value denotes the percentage to the rated inverter current. It is not the percentage to the rated motor current.
When you set the electronic thermal relay function dedicated to the Mitsubishi Electric constant-torque motor, this characteristic curve applies to
operation at 6 Hz or higher. (For selection of the operation characteristic, refer to
Transistor protection is activated depending on the temperature of the heatsink. The protection may be activated even with less than 150%
depending on the operating conditions.
• The internal accumulated heat value of the electronic thermal O/L relay is reset to the initial value by the inverter's power reset
or reset signal input. Avoid unnecessary reset and power-OFF.
• Install an external thermal relay (OCR) between the inverter and motors to operate several motors, a multi-pole motor or a
dedicated motor with one inverter. When setting an external thermal relay, note that the current indicated on the motor rating
plate is affected by the line-to-line leakage current. (Refer to
operation. Use a thermal protector or a motor with built-in thermistor.
• The protective characteristic of the electronic thermal O/L relay is degraded when there is a large difference in capacity
between the inverter and motor, and when the set value is small. In this case, use an external thermal relay.
• Dedicated motors cannot be protected by an electronic thermal O/L relay. Use an external thermal relay.
• The transistor protection thermal O/L relay is activated earlier when the Pr.72 PWM frequency selection setting is increased.
Electronic thermal O/L relay pre-alarm (TH) and warning signal (THP
• If the accumulated electronic thermal value reaches 85% of the
(TH) is displayed and the electronic thermal O/L relay pre-alarm (THP) signal is output. If the value reaches 100% of the
setting, the electronic thermal O/L relay function (E.THM/E.THT) is activated to shut off the inverter output. The inverter
output is not shut off with the TH display.
• For the terminal used for the THP signal, assign the function by setting "8 (positive logic) or 108 (negative logic)" in
(Output terminal function selection)
Electronic thermal O/L
relay alarm (THP)
• Changing the terminal assignment using Pr.195 (Output terminal function selection) may affect the other functions. Set
parameters after confirming the function of each terminal.
Pr. 9 = 100% setting
of inverter rating*
30Hz or more*
Region on the right of
Region on the left of
electronic thermal relay
function for motor
protection is turned off
(When Pr. 9 setting is 0(A))
. (This setting enables the 100%
Pr.71 Applied motor
48.) The cooling effect of the motor drops during low-speed
setting, electronic thermal O/L relay function pre-alarm
5.6 (H) Protective function parameter