Method and apparatus for determining the power factor of a circuit
US4851635A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 14, 1988 |
| Grant date | Jul 25, 1989 |
| Priority date | — |
| Expiry date | Jul 14, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K11/252
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Structure for and method of controlling the firing point of thyristors in a phase controlled contactor in a resistance welding circuit in accordance with variations in current line voltage and/or one of resistance and inductive impedance in the welding circuit including structure for and the method of determining the firing point in a cycle of alternating electrical energy fed to the welder in terms of its distance from zero voltage cross over point and determining the current lag after a subsequent zero voltage cross over point of the voltage signal, determining the power factor of the welding circuit from these angular measurements and selecting a new firing delay for the contactor in accordance with the circuit power factor and the percent heat selected in the welding circuit, and subsequently correcting the firing delay in accordance with the percent heat selected in view of changes in the line voltage and circuit current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.