103
Selection and protection of a motor
(3) External thermal relay input (OH signal)
(4) PTC thermistor protection (Pr. 561)
To protect the motor against overheat, use the OH signal when using an external
thermal relay or the built-in thermal protector of the motor.
When the thermal relay operates, the drive unit trips and outputs the fault signal
(E.OHT).
For the terminal used for OH signal input, assign the function by setting "7" in any of
Pr. 178 to Pr. 182 (input terminal function selection)
.
External thermal relay input
connection example
NOTE
Changing the terminal assignment using
Pr. 178 to Pr. 182 (input terminal function selection)
may affect the other
functions. Set parameters after confirming the function of each terminal.
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 134)
, or RS-485
communication
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.
Drive unit
U
V
W
OH
SD
Thermal relay
protector
Motor
M
Drive
unit
Motor
U
V
W
10
2
PTC thermistor
R2
R1
Pr. 561
TN
TN+
Δ
T
TN-
Δ
T
Thermistor
temperature
TN: Rated operational temperature
Thermistor
resistance
Thermistor curve
Temperature-resistance
existing range
Содержание FR-D720-0.2K-G
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Страница 294: ...291 APPENDIX This chapter provides the APPENDIX of this product Always read the instructions before using the equipment ...