Mitsubishi Electric FR-F800 Series Instruction Manual page 272

NOTE
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) may affect the other functions.
Set parameters after confirming the function of each terminal.
 PTC thermistor input (Pr.561, Pr.1016, E.PTC)
This function is used to protect the motor from overheating by inputting outputs from the motor's built-in PTC thermistor to the
inverter. It is recommended that a PTC thermistor whose resistance increases most rapidly around the rated activating
temperature (TN±DT) is used.
PTC thermistor input connection diagram
• Output from the PTC thermistor, which is built into the motor, 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, the PTC thermistor operation
(E.PTC) shuts off the inverter output.
• To use the PTC thermistor input function, select voltage input (initial setting) for terminal 2 using the voltage/current input
selection switch. (For details on the voltage/current input switch assembly, refer to
• 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.
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Inverter
Motor
U
V
W
10
2
PTC thermistor resistance
The elapsed time count is cleared.
Pr.561
setting
ALM
search engine
Thermistor resistance
R2
Pr.561
R1
Temperature - resistance
TN-DT
existing range
TN: Rated operating temperature
Example of PTC thermistor characteristics
Pr.1016
E.PTC
Thermistor curve
Thermistor temperature
TN+DT
TN
page 349.)
page 305.)
Time
5.7 (H) Protective function parameter
1
2
3
4
5
6
7
8
9
10
271
5. PARAMETERS