A motor driven actuator has a housing enclosing an electric motor having connections for receiving current from a power supply, a control module, a drivetrain for connecting an external device to be actuated to the electric motor, and a temperature sensing device to detect measured temperature T within the housing. The control module receives the measured temperature immediately after the actuator is powered on. If the measured temperature is less than a predetermined temperature TOFF and the actuator is in an inactive state, then a heating programme is initiated. The heating programme passes a current from the power supply through the motor to generate heat within the motor and to control the motor such that the motor remains substantially stationary with no net movement for the duration of the heating programme. The current passing through the motor may be pulsed between first and second directions to drive the motor in first and second directions respectively, where the first and second direction pulses are substantially equal in duration.
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