Low burden visual power-on indicator for a self-powered circuit protection device
US5510773A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 14, 1994 |
| Grant date | Apr 23, 1996 |
| Priority date | — |
| Expiry date | Oct 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H1/066
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides a low burden visual POWER ON indicator for a self-powered electrical circuit protection device. The visual indicator includes a current transformer for producing an induced current in direct proportion to the current supplied to an electrical device protected by the protection device. The induced current is summed and rectified. An energy accumulator stores a predetermined voltage required to operate the protection device. The stored voltage is controlled by an accumulation switch which in turn is controlled by a hysteresis control circuit. The hysteresis control circuit includes an operational amplifier which is biased by a stable reference voltage. When the voltage on the energy accumulator is equal to the stable reference voltage the operational amplifier produces a HIGH output signal. When the voltage on the energy accumulator is less than the stable reference voltage the operational amplifier produces a LOW output signal. A HIGH output signal causes the power accumulation switch to close thereby diverting current away from the energy accumulator. A LOW output signal opens the power accumulation switch causing current to flow to the energy accumul…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.