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:
Apr. 18, 1989
Filed:
Dec. 10, 1985
Wolfgang Millauer, Munich, DE;
Hilti Aktiengesellschaft, , US;
Abstract
A circuit for phase control of an AC-DC motor for a machine operated in defined (preferably two) load conditions with a controllable current flow control valve located in series with the motor and associated triggering pulse stage. The circuit includes a measuring circuit designed as a rectifier circuit with filter link for detection of the load current flowing through the load path of the current flow controller or through the motor as well as a threshold value circuit which determines a first basic desired value of the triggering voltage level at the triggering pulse stage at low load current values (idling). If a triggering threshold, adjustable at the triggering value circuit, is exceeded, then the triggering voltage level is switched over onto a second firmly or permanently adjusted value, so that the motor now operates at nominal load with nominal rpm through the current flow control valve, now controlled to be fully advanced. The circuit does not require any information about the instantaneous rpm and is distinguished by its simple construction and reliable operation. It is particularly suitable for utility machines, which operate either in idling or under nominal load conditions.