Electrical motor e.g. commutator motor with thermal protector, has cutoff contact which makes contact with external edge of brush holder in case of overload causing softening of brush spring and displacement of brush holder

摘要

A bearing shield (26) has a tongue forming an inwardly bent cutoff contact (50) at a gap (f) from an external edge (52) of a metallic brush holder (32). The heat generated by overloading of motor softens a thermoplastic brush carrier (46) such that the force of a brush spring (34) displaces the brush holder radially of a motor shaft (18) towards outside, thus, causing the cutoff contact to come into contact with the external edge of the brush holder to initiate a short circuit and disconnect power supply from the motor.