Electric motor control

摘要

A start-up switch 50 for an electric motor 1 comprises a resistive element (54) which is so constituted as to be connectable to an electric current path (15) and which has such a characteristic that its resistance value increases by the heat generated by electric current that flows through the electric current path (15) and a thermostatic switch (60) which is connected in series with the resistive element (54). The thermostatic switch (60) has an actuation member (60) which is responsive to temperature so that upon reaching a preselected temperature, said member moves from a closed current path position to an open current path position. The thermostatic switch (60) is positioned to be in direct heat transfer relationship with the resistive element (54) so that the member will (66) rise in temperature as the resistive element (54) rises in temperature.