Thermal Protection; Alarm Tripping With Ptc Thermistors - Parker MGV Series Technical Manual

3.6. Thermal Protection

Protection against thermal overloading of the motor is provided by one PTC
thermistors and one KTY temperature sensor (and one more in case of KTY failure)
built into the stator winding as standard. All thermal protection wires section is
AWG26.
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3.6.1.
The thermal probes (PTC thermistors) fitted in the servomotor winding trip the
electronic system at 150° ± 5° C. When the rated tripping temperature is reached, the
PTC thermistor resistance changes very quickly. This resistance can be monitored by
the drive to protect the motor.
The graph and tab below
shows the PTC resistance
as a function of temperature
(TN is nominal temperature)
Temperature
-20°C up to TN-20°C R≤250Ω
TNF-5°C
TNF+5°C
TNF+15°C
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Alarm tripping with PTC thermistors :

Resistance (Ω)
4000Ω
Resistance
1330Ω
value
R≤550Ω
550Ω
R≥1330Ω
R≥4000Ω
250Ω
57 - PVD3627-August 2011
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-
-
+ +
Brown
Temperature (°C)