Mitsubishi Electric 800 Series Instruction Manual (Function page 283

• Outputs from the motor's built-in PTC thermistor can be input to terminals 2 and 10. If the input from the PTC thermistor
reaches the resistor value set in Pr.561 PTC thermistor protection level, E.PTC (PTC thermistor operation) shuts off the
inverter output.
• Confirm the characteristic of the PTC thermistor to be used, and set the resistance for Pr.561 around the center of the R1
and R2 values shown on the figure above so that it does not deviate from the protective function activating temperature
TN. If the Pr.561 setting becomes too close to R1 or R2, the protective function activating temperature may be too hot
(protection is delayed), or too cold (too much protection).
• When the PTC thermistor protection is enabled (Pr.561 ≠ "9999"), the resistance value for the PTC thermistor can be
displayed on the operation panel or via RS-485 communication. (Refer to
• When the PTC thermistor protection level setting is used, use Pr.1016 PTC thermistor protection detection time to set
the time from when the resistance of the PTC thermistor reaches the protection level until the protective function (E.PTC)
is activated.
• If the resistance of the PTC thermistor falls below the protection level within the protection detection time, the elapsed time
count is cleared.
NOTE
• When using terminal 2 for PTC thermistor input (Pr.561 ≠ "9999"), terminal 2 does not operate as an analog frequency
command terminal. When a function for the PID control or dancer control is assigned to terminal 2, the function is disabled.
Use Pr.133 PID action set point to set the set point for the PID control. When the PID control and dancer control are disabled
(Pr.128 PID action selection = "0") and Pr.858 = "0", terminal 4 operates as follows.
Pr.79 = "4" or External operation mode is selected: Terminal 4 input is valid regardless of ON/OFF state of the AU signal.
Pr.79 = "3": Frequency command given via terminal 4 is valid only when the AU signal is ON.
• To input power to the PTC thermistor power supply, always use the terminal 10 and do not use any other terminals or an
external power supply. Otherwise, E.PTC (PTC thermistor protection) does not operate properly.
• When E.PTC is activated, the alarm display, "External protection (AU terminal)", may appear on the parameter unit (FR-PU07),
but it is not a fault.
 Overheat protection to match the characteristic of the motor (Pr.600 to
Pr.604, Pr.692 to Pr.696)
• The activation level of the electronic thermal O/L relay can be varied to match the motor temperature characteristic.
• The electronic thermal O/L relay operation level can be set with the combination of three points (Pr.600, Pr.601), (Pr.602,
Pr.603), (Pr.604, Pr.9). Two or more points are required for setting.
282
12. (H) Protective Function Parameters
12.1 Motor overheat protection (electronic thermal O/L relay)
PTC thermistor resistance
The elapsed time count is cleared.
Pr.561
setting
ALM
page 310.)
Time
Pr.1016
E.PTC