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:
Jun. 28, 1983
Filed:
May. 26, 1981
Reginald B Tharrington, Broken Arrow, OK (US);
Telex Computer Products, Inc., Tulsa, OK (US);
Abstract
An electronic switching system for inductive loads in A.C. circuits, comprising a triac switch in series with an inductive load such as transformer or motor, etc. across an A.C. voltage. The control voltage for the triac switch is provided by a smaller, lower power triac driver, which has a light emitting diode controlled by an optically isolated transistor. The optically isolated transistor is provided with electrical pulses each a half cycle of voltage by means of a zero crossing detector. Since it is impossible to know precisely what the power factor of the load is, the triggering of the triac driver is provided at zero voltage on both the upward and downward crossing. These pulses, amplified by the transistor, control the triac driver. The load current will lag the voltage by some angle, dependent on the power factor, and the current will stop at its zero point. The triac driver has its control voltage at the zero of voltage and, therefore, has a control ready to ignite the triac as soon as the current in the reverse direction passes to zero.