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93
Selection and protection of a motor
4
PARAMETERS
(4) PTC thermistor protection (Pr. 561)
PTC thermistor input connection
PTC thermistor characteristics
PTC thermistor output can be input to the terminals 2 and 10.
When the PTC thermistor input reaches the resistance value set
in Pr. 561 PTC thermistor protection level, drive unit outputs PTC
thermistor operation error signal (E.PTC) and trips.
Check the characteristics of the using PTC thermistor, and set
the resistance value within a protection providing temperature
TN, just around the center of R1 and R2 in a left figure. If the Pr.
561 setting is closer to R1 or R2, the working temperature of
protection goes higher (protection works later), or lower
(protection works earlier).
PTC thermistor resistance can be displayed in operation panel,
parameter unit (FR-PU07) (Refer to page 117), or RS-485
communication (Refer to page 164) when PTC thermistor
protection is active (Pr. 561 ≠ "9999").
REMARKS
When using terminal 2 as PTC thermistor input (Pr. 561 ≠ "9999"), terminal 2 is not available for analog speed command. Also
unavailable when using terminal 2 for PID control. When PID control is not active (Pr. 128 PID action selection = "0"), terminal 4
functions as follows.
When Pr. 79 = "4" or in External operation mode................Terminal 4 is active whether AU signal is ON/OFF
When Pr. 79 = "3"................................................................Terminal 4 is active for speed command when AU signal is ON
For the power supply terminal of PTC thermistor input, do not use power supply other than terminal 10 (external power supply,
etc). PTC thermistor does not work properly.
Parameters referred to
Pr. 79 Operation mode selection Refer to page 147
Pr. 128 PID action selection
Refer to page 199
Pr. 178 to Pr. 182 (input terminal function selection)
Refer to page 100
Pr. 190, Pr. 192 (output terminal function selection)
Refer to page 106
Drive
unit
Motor
U
V
W
10
2
PTC thermisto
R2
R1
Pr. 561
TN
TN+ΔTTN-ΔT
Thermistor
temperature
TN: Rated operational temperature
Thermistor
resistance
Thermistor curve
Temperature-resistance
existing range