YU26200A - Switch for the protection of monophase electromotor - Google Patents

Abstract

The essence of the invention is the protection of the monophase electromotor from overloading, so that the primary of the transformer (2) is piaced in the series connection with the electromotor, the fall of voltage on it is placed in direct proportion to the power of electricity received by electromotor. The bulb (4) is connected to the primary of the transformer (2), placed in a box together with the photo diode (14), without the influence of outer light, so that photo diode has resistence depending on the power of electricity of electromotor (1). Condenser (17) is charged by electricity conducted by photo diode, from the capacitiveness of this condenser and the resistence of photo diode depends the time that electromotor needs to accomplish nominal speed, without being switched off. The charging of the condenser (20) by way of the resistence (19) determines the time of work of electro motor at nominal load. When the resistence between the coils and the mass is reduced, electromotor should be switched off to prevent further damage. It is achieved by connecting the primary of the transformer (3) to the serial connection with the electromotor and the secundary is connected to the miliampermeter (6), that is, like in the picture 2, connected to transistor (24) and reley (25) for the purpose of switching the electromotor off.