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. 12, 1981
Filed:
May. 21, 1979
Richard W Roof, West Columbia, SC (US);
Square D Company, Palatine, IL (US);
Abstract
A pre-step timer circuit for pre-advancing the next timer period (control step) in a DC motor controller, such as in a crane-hoist controller. A sensing resistor module is connected from the line side of a contactor coil of a preceding control step to the input of a timer module in series with the accelerating contactor coil in the next control step. This resistor module sensing the previous coil voltage provides a feed-forward path for the sensed voltage signal to pre-time the next timer module. So, if a master switch is left in the previous control step long enough for the next timer module to time out, then the next control step is actuated immediately when the master switch is advanced thereto.