Circuit breaker static trip unit having automatic circuit trimming
US4550360A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 21, 1984 |
| Grant date | Oct 29, 1985 |
| Priority date | — |
| Expiry date | May 21, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/0935
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An analog signal processor used within a static trip unit is provided with an A/D converter, a digital processor and an electrically alterable non-volatile memory (EAROM) for providing trimming and calibration facility to the trip unit. The EAROM provides the ability to store parameters calculated by the user during the manufacturing process of the trip unit. Key measured or environmental variables are created and a correction algorithm is generated and stored along with data. The trip unit is then capable of self-calibration by applying the correction factor to compensate for variations in the component sensitivity. In one application, the current sensing transformer is precalibrated and provided with a correction factor and a correction algorithm. In another application, the thick film resistors within the long term trip mode network, the short term trip mode network and the power supply voltage regulator are "trimmed" by means of stored correction values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.