EN IEC 60730-2-22:2020

Automatic electrical controls - Part 2-22: Particular requirements for thermal motor protectors

Publication date:   Jul 15, 2020

Scope

IEC 60730-2-22:2014 applies to the partial evaluation of thermal motor protectors as defined in IEC 60730-1 for household and similar use, including heating, air conditioning and similar applications as well as for sealed (hermetic and semi-hermetic type) motor-compressors. A thermal motor protector is considered an integrated control since its protective functionality is dependent on the correct mounting and fixing in or on a motor and which can only be fully tested in combination with the relevant motor. This dependency is illustrated by:

- the ability of the thermal motor protector to accurately and reliably sense the heat of the motor windings;

- thus, addressing the over-temperature protection due to motor overload conditions;

- the ability of the thermal motor protector to accurately and reliably sense the current due to motor locked-rotor conditions;

- thus, reducing the response time and not being adversely affected by heat-sink at the assembly spot in the application and the influence of the motor's electromagnetic field on the switch behaviour of the thermal motor protector;

- particularly, affecting the arc direction between the contacts resulting in uneven wear of the contact material and eventually leading to failure of operation. Requirements concerning the testing of the combination of sealed (hermetic and semi-hermetic type) motor-compressors and thermal motor protectors are given in IEC 60335-2-34. This standard applies to thermal motor protectors using NTC or PTC thermistors, additional requirements for which are contained in Annex J.
Key words: Thermal, Motor protectors, Integrated control

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