Method and apparatus for measuring the current flowing in a workpiece
US4059798A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 8, 1976 |
| Grant date | Nov 22, 1977 |
| Priority date | — |
| Expiry date | Mar 8, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/025
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Magnetic cores of clamp-on type current measuring devices having a Hall-effect device for measurement of D.C. currents are provided with stabilizing coils which are periodically energized to substantially eliminate the characteristic hysteresis effect of the core material. A magnetic core of the type which is split to permit opening and subsequent clamping onto a conductor, has one section thereof provided with an air gap in which the Hall-effect device is positioned. A stabilizing coil is positioned on one section of the magnetic core and the coil and is periodically energized with a damped oscillatory current. This damped oscillatory current is at least applied immediately prior to the taking of any current measurement and is preferably applied periodically to maintain the stability of the magnetic core.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.