prEN IEC 60034-11:2020

This part of IEC 60034 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. Not included are: • direct protection of the rotor winding; the methods of protection only protect rotor windings indirectly; for large motors (particularly 2 pole motors) and for motors starting large inertia loads, special attention needs to be given to rotor heating both when starting and especially after a "trip" has occurred; • the protection of bearings and other mechanical parts; • the protection methods to be used for particular applications. NOTE 1 Although temperature values given in this standard are higher than those specified in IEC 60034-1, they are not in conflict. NOTE 2 Additional requirements may apply to particular motor types such as those used in household appliances, or for motors used in explosive atmospheres.