Thermal motor protection

Thermal motor protection avoids overheating and, therefore, prevents irreparable damage to the motor. For this purpose, temperature sensors detect the winding temperature. As standard, the inverters can evaluate the following temperature sensors.

Note that the KY/KTY, PK, and PI temperature sensors cannot be connected in series by several motors. For further information, refer to chapter Group drive and multi-motor drive.

Motor protection

Number of sensors

SEW-EURODRIVE
designation

PTC thermistor

3

TF

Bimetallic temperature switch

3

TH

Semiconductor temperature sensor KTY84-130

1

KY/KTY

Pt1000 platinum temperature sensor,
mounted in winding

1

PK

Pt1000 platinum temperature sensor,
mounted in stator housing

1

PI

Motor series

Number of sensors

Motor protection

CM..

KTY84-130 (KY/KTY), Pt1000 (PK)

Comprehensive protectionComprehensive protection, as a thermal model protects the winding in addition to the measured value.

PTC thermistor (TF)

Limited protectionDepending on the motor size.

DR..

PTC thermistor (TF)
Bimetallic temperature switch (TH)

Comprehensive protectionComprehensive protection due to one sensor per motor phase.

Semiconductor temperature sensor KTY84-130 (KY/KTY)

Limited protectionIf the temperature measured by the temperature sensor exceeds the limit temperature of the set thermal class of the motor, the inverter issues a fault message. There is no evaluation of the motor model. Thermal overload of windings is possible since the sensor is only installed in one winding.

Pt1000 platinum temperature sensor
Mounted in winding (PK)

Limited protectionIf the temperature measured by the temperature sensor exceeds the limit temperature of the set thermal class of the motor, the inverter issues a fault message. There is no evaluation of the motor model. Thermal overload of windings is possible since the sensor is only installed in one winding.

Pt1000 platinum temperature sensor
Mounted in stator housing (PI)

Comprehensive protectionComprehensive protection, as a thermal model protects the winding in addition to the measured value.

Third-party motors

PTC thermistor,
bimetallic temperature switch

Comprehensive protectionComprehensive protection due to one sensor per motor phase.

KTY84-130, Pt1000

Limited protectionIf the temperature measured by the temperature sensor exceeds the limit temperature of the set thermal class of the motor, the inverter issues a fault message. There is no evaluation of the motor model. Thermal overload of windings is possible since the sensor is only installed in one winding.

For additional information on the thermal motor protection, refer to the documentation of the motors.