Unity gain filter for current transformer
US5519560A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1994 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Mar 1, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R15/183
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electrical device such as an electrical contactor interfaces at least one alternating current transformer having an output providing a signal proportional to changes in alternating current and includes at least one filter for filtering the output signal of the transformer. Each of the filters have an input connected to the transformer and an output having a signal proportional to the transformer output signal and inversely proportional to selected frequencies of the alternating current. The electrical device also has means for determining a value related to the alternating current using the output of each of the filters. The filter may have a resistor and a capacitor for filtering the transformer output signal in order that the filter is a low-pass filter. Alternatively, the filter may be a band-pass filter. The electrical device may include a microcomputer having an integrating capacitor and an analog-to-digital converter for converting the output of each of the filters to a digital value related to, or equal to, the alternating current. Alternatively, the electrical device may have a rectifier for inverting an output signal of each of the filters and a summer for summing only …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.