The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 12, 1986
Filed:
Feb. 17, 1984
In S Kim, Kangnam-ku, Samig, KR;
Other;
Abstract
The switching device of the present invention electrically connects a single-phase induction motor's starting winding to the motor's circuitry upon start-up, and disconnects it once the motor reaches a first predetermined speed. If the motor's speed drops below a second predetermined speed, the switching device reconnects the starting winding to the motor's circuitry until the motor again reaches the first predetermined speed. At start-up, diode bridge D1 turns ON, turning ON SCR S2. With the SCR ON, the diode bridge is short-circuited, drawing a large current through the bridge's a.c. side. This current flows through resistor R8, and the voltage drop across R8 is large enough to turn triac S1 ON. Thus, current flows through starting coil L2. When the motor reaches a first predetermined speed, the voltage across the starting coil is large enough to turn NPN transistor TR2 ON, turning PNP transistor TR1 ON. Accordingly, the SCR turns OFF, eliminating the large current drawn through the a.c. side of the diode bridge, and the triac turns OFF. If the motor speed dips below a second predetermined value, lower than the first, transistor TR1 is cutoff, and the triac subsequently turns back ON until the first predetermined speed is reached.