Weld current sensor
US5221894A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 2, 1992 |
| Grant date | Jun 22, 1993 |
| Priority date | — |
| Expiry date | Mar 2, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/16509
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A weld current switch includes a channel-shaped core, a shunt, and a magnetic reed switch. The magnetic reed switch and shunt are placed across the core poles. An electrical conductor carrying high current passes through the core. Upon deenergization of the electrical current, a residual magnetism remains in the core. The residual magnetism is normally high enough to prevent the magnetic reed switch from opening. However, the shunt directs sufficient magnetic flux from the switch such that the switch senses a much lower level of magnetic flux than if the shunt were not present. As a result, the switch opens, even with the high residual flux in the core. The increased reliability of the switch upon decreasing current at electrical conductor deenergization enables the weld current switch to use a higher sensitivity switch than was formerly possible. The higher sensitivity switch reduces the level of magnetic flux at which the reed switch will close on increasing current upon energization of the electrical conductor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.