3.3.10 PTC Thermistor Connection
Motor protection can be implemented using a range of
techniques: PTC or KTY sensor (see also section
KTY Sensor
Connection
) in motor windings; mechanical thermal switch
(Klixon type); or Electronic Thermal Relay (ETR).
Using a digital input and 24 V as power supply:
Example: The adjustable frequency drive trips when the
motor temperature is too high.
Parameter set-up:
Set
Thermistor Trip
[2]
Set
to
Digital Input
[6]
Using a digital input and 10 V as power supply:
Example: The adjustable frequency drive trips when the
motor temperature is too high.
Parameter set-up:
Set
Thermistor Trip
[2]
Set
to
Digital Input
[6]
Using an analog input and 10 V as power supply:
Example: The adjustable frequency drive trips when the
motor temperature is too high.
Parameter set-up:
Set
to
Thermistor Trip
[2]
Set
Analog Input 54
[2]
Input
Digital/analog
Supply Voltage
Threshold
Cut-out Values
Digital
24 V
< 6.6 k
Ω
- > 10.8 k
Ω
Digital
10 V
< 800
Ω
- > 2.7 k
Ω
Analog
10 V
< 3.0 k
Ω
- > 3.0 k
Ω
NOTE!
Ensure that the chosen supply voltage follows the specifi-
cation of the thermistor element utilized.
Parameter Descriptions
FC 300 Programming Guide
MG.33.MA.22 - VLT
®
is a registered Danfoss trademark
3-25
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