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. 15, 1980
Filed:
Mar. 23, 1978
Hans Laber, Erlangen, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
Three voltage transformers have primary windings whose first ends are connected, respectively, to three a-c leads of a static converter and whose second ends are connected together to form an artificial neutral point. A high value resistor is connected between the neutral point and ground and a current-measuring means measures the current flowing in the resistor and generates an alarm signal in the event such current indicates a ground in the converter. Also disclosed is an arrangement including two high voltage converters connected to each other through smoothing chokes to form a frequency changer or converter in which the two converters have substantially identical circuit arrangements for detecting grounds with the circuit arrangements for detecting grounds having their outputs connected to each other.