INSTRUCTIONS AND MAINTENANCE MANUAL
MAC R MOTORS
PAGE:
27
CODE: CTT12 EDITION: 01 DATE: MAY 2013
Subject to technical changes without prior notice
3.7.4
Standard thermal protection
MAC R motors include a PTC140-type thermistor on their stator windings. It is a solid-state device of the variable
resistive type that provides a
Contact Open (OFF) / Contact Closed (ON)
type logical signal depending on
whether or not the temperature of the motor windings exceeds the reference temperature of the sensor, in this
case 140°C.
Its operation curve is as follows:
Figure 6: Characteristic curve of a PTC140
Said ON/OFF logical signal can be used by an external control circuit to process an alarm system to prevent the
motor from overheating.
