Thermally protected electric motor

A thermally protected electric motor, comprising:

• a housing having an end cap;
• a rotor, incorporating a commutator, mounted within the housing;
• brushes engaging the commutator, and two terminals for connecting the brushes to an external electrical supply, the brushes and terminals being mounted within the end cap;
• a laminated, metal-polymer-metal PTC resistor mounted within the end cap and having two transversely spaced parts and, on opposite sides, two substantially parallel opposed surfaces;
• two electrically conductive contact members connected, respectively, to one of the brushes and to one of the terminals and respectively having contact portions which make point contact with the two substantially parallel opposed surfaces and which each have a neck portion disposed between the contact portion and the remainder of the contact member;
• said two electrically conductive contact members respectively engaging the two substantially parallel opposed surfaces for making substantial electrical contact at a limited area of contact with the PTC resistor, and exerting a sufficiently low contact pressure on the PTC resistor such that the contact members do not change the electrical characteristics of the PTC resistor, and such that at least one of the contact members provides substantially no support for the PTC resistor against movement perpendicular to said opposed surfaces;
• and
• thermally insulating supporting means in the form of two abutments, in the end cap, which engage and thereby directly support the PTC resistor against movement perpendicular to the substantially parallel opposed surfaces, and cooperate, respectively, with the two contact members to clamp the two parts of the PTC resistor.