Abstract: An electric motor inlcudes a slotted collar on the rotor and a temperature sensitive actuator with an attached pin effective when cold to move into an inserted position in which the pin engages the slotted collar to prevent rotor rotation, and when hot to move to a retracted position in which the pin is withdrawn from the collar to allow rotor rotation. The actuator comprises first and second springs having ends connected together and exerting opposing forces on each other, the second spring being made of a temperature sensitive memory metal so as to shorten and lengthen the actuator with changing temperature. The acutator is electrically conducting and inserted in series with the motor commutator, whereby armature current heats the actuator to move to the retracted position, and cessation of armature current allows it to cool and move to its inserted position.