Patent · US Expired

Method and device for preventing excessive currents in a welding converter

US5570254A · kind A · utility

10Cited by

3References

10Claims

0Family size

Assignee

Robert Bosch GmbH · DE

Inventors

Gerhard Spilger · Beerfelden, DE
Thomas Klinger · Ingolstadt, DE
Dieter Stellwag · Erbach, DE

Key dates

Filing date	Apr 7, 1994
Grant date	Oct 29, 1996
Priority date	—
Expiry date	Apr 7, 2014

Classification

Technology area (CPC H)Electricity
CPC primaryH02H3/44
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

A method for preventing excessive currents in a welding converter that, by use of power semiconductors, generates a two-phase, pulse-width-modulated a.c current from a rectified mains a.c. current supplied to the primary side of a welding transformer. The method includes the following method steps: detecting the current of at least one phase of the primary circuit by a sensor (20); for each detected current signal, forming the time derivation through differentiation according to the time; comparing the time-derived measured signal with a predetermined maximum value; and if the time-derived measured signal exceeds the predetermined maximum value, emitting a signal that leads to deactivation of the power semiconductors (16).

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.