Siemens SIMOTICS Series Hardware Installation Manual

Motor components, characteristics and options
4.1 Thermal motor protection
SIMOTICS M-1FE2 built-in motors
60 Hardware Installation Manual, 04/2020, A5E50074509B AA
4.1.2 Temperature evaluation using the PTC thermistor triplet (full motor protection)
For special applications (e.g. when a load is applied with the motor stationary or for
extremely low speeds), the temperature of all of the three motor phases must be additionally
monitored using a PTC thermistor triplet.
Note
If water
-cooled built-in motors are operated fo
r longer than one minute at a standstill with the
standstill torque, one phase can be disproportionately loaded thermally.
•
Reduce the permanent standstill torque by up to 20 %.
•
Protect the winding thermally with a thermistor triplet (PTC) with an external tripping unit.
The PTC thermistor triplet can be evaluated using an external tripping unit (this is not
included in the scope of delivery). This means that the sensor cable is monitored for wire
breakage and short-circuit by this unit.
The motor must be de-energized within 1 second when the response temperature is
exceeded.
Table 4- 2 Technical specifications for the PTC thermistor triplet
Designation
Technical specifications
Type (acc. to DIN 44082–M180)
PTC thermistor triplet
Thermistor resistance (20° C)
≤ 750 Ω
Resistance when hot (180° C)
≥ 1710 Ω
Connection
Via an external trip unit
Cable cross-section/outer diameter
0.14 mm
2
/0.9 mm
Response temperature
180 °C
Note:
PTC thermistors do not have a linear characteristic curve and are, therefore, not suitable for
determining the instantaneous temperature.
Note
PTC thermistors are ESD components
Carefully observe the ESD instructions.

Siemens SIMOTICS Series Specifications

General

Brand	Siemens
Model	SIMOTICS Series
Category	Engine
Language	English