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. 22, 1989
Filed:
Jan. 19, 1988
David A Wolze, San Jose, CA (US);
Impact Systems, Inc., San Jose, CA (US);
Abstract
A controller for a load such as the heater elements of an actuator for drying the various zones or slices of a moving sheet of a papermaking machine includes silicon controlled rectifiers for each zone or slice of the moving sheet whose firing angle is controlled by an external power command signal. This power command signal is processed by a digital signal processor which strobes at a high rate the line voltage and load current to provide a closed loop feedback control technique for power being applied to the load and in addition, the processor, at the same time, has an open loop firing angle control routine which has a fast response time to protect against abnormal conditions within one-half cycle of load voltage.