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:
May. 02, 1978
Filed:
Oct. 01, 1976
Robert W Johnson, Levittown, PA (US);
ESB Incorporated, Philadelphia, PA (US);
Abstract
A system for rapidly substituting one source of AC power for another. A solid-state gated electronic valve is coupled in circuit with a principal power source or 'line' and the current through the valve is monitored. Line voltage is also monitored and a timing signal produced to keep the system in synchronism with the principal power source. When the source voltage decreases or changes abruptly, or if its phase drifts unacceptably, the difference detected between the source and a reference effects the termination of valve gating signals, and allows the application of synchronous enabling signals to a standby power source. If the solid-state valve is non-conducting the standby source starts immediately in synchronism with the previously-supplied load voltage. If current is flowing in the valve, however, a commutating signal is produced which overrides the synchronous standby enabling signal to energize the standby power source with the proper polarity to extinguish current through the valve. When the current decreases below the holding current value the standby source is caused to enter the synchronous mode.