IEC 60034-11:2020 specifies requirements relating to the use of thermal protectors and thermal detectors incorporated into the stator windings or placed in other suitable positions in induction machines in order to protect them against serious damage due to thermal overloads. It applies to single-speed three-phase 50 Hz or 60 Hz cage induction motors in accordance with IEC 60034-1 and IEC 60034-12 that:
- have a rated voltage up to 1 000 V;
- are intended for direct-on-line or star-delta starting.
The main changes with respect to the previous edition are:
- the additional specification of winding temperature limits for temperature class 200 (N),
- the increased limits of maximum winding temperatures for overloads with rapid variation,
- the clarification that the motor winding may be permanently damaged after it has been exposed to temperatures
- a clarification of the definition of indirect thermal protection,
- a clarification on the test methods for larger motors.