Thermisch geschützter elektrischer Motor.

摘要

A laminated, metal-polymer-metal PTC resistor (8) is held in the end cap (2) of an electric motor. Opposite transverse surfaces (9 and 10) of the PTC resistor (8) are engaged by electrically conductive members (11 and 12) which are respectively connected to one of the brushes (5) and one of the motor terminals (6) so that the supply of electricity is interrupted when the PTC resistor (8) is heated above a predetermined temperature as a result of excessive current flow. The PTC resistor (8) is supported against movement perpendicular to the transverse surfaces (9 and 10), at least in one direction, and therefore independently of at least one of the contact members (11 and 12) so that, at most, only one of the contact members (11 and 12) is needed for supporting the PTC resistor (8). Both contact members (11 and 12) can therefore make point contact with the PTC resistor (8) and this improves operation by inhibiting the conduction of heat to or from the PTC resistor (8).