2.4.9. 1-9* Motor Temperature
Parameters for setting the temperature protection features for the motor.
1-90 Motor Thermal Protection
Option:
Function:
The frequency converter determines the motor temperature for motor protection in two different ways:
•
Via a thermistor sensor connected to one of the analog or digital inputs (par. 1-93
Thermistor
Source
).
•
Via calculation (ETR = Electronic Terminal Relay) of the thermal load, based on the actual load and
time. The calculated thermal load is compared with the rated motor current I
M,N
and the rated motor
frequency f
M,N
. The calculations estimate the need for a lower load at lower speed due to less cool-
ing from the fan incorporated in the motor.
[0]
*
No protection
Continuously overloaded motor, when no warning or trip of the frequency converter is required.
[1]
Thermistor warning
Activates a warning when the connected thermistor or KTY-sensor in the motor reacts in the event of motor
over-temperature.
[2]
Thermistor trip
Stops (trips) frequency converter when connected thermistor in motor reacts in the event of motor over-tem-
perature.
The thermistor cut-out value must be > 3 k
Ω
.
Integrate a thermistor (PTC sensor) in the motor for winding protection.
[3]
ETR warning 1
[4]
ETR trip 1
[5]
ETR warning 2
[6]
ETR trip 2
[7]
ETR warning 3
[8]
ETR trip 3
[9]
ETR warning 4
[10]
ETR trip 4
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 frequency converter trips when the motor temperature is too high
Parameter set-up:
Set Par. 1-90
Motor Thermal Protection
to
Thermistor Trip
[2]
Set Par. 1-93
Thermistor Source
to
Digital Input
[6]
FC 300 Programming Guide
2. How to Programme
MG.33.M3.02 - VLT
®
is a registered Danfoss trademark
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