Electronic overload relay having intrinsic power supply operable from power applied to contactor coil
US5715129A · kind A · utility
4Cited by
8References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 5, 1995 |
| Grant date | Feb 3, 1998 |
| Priority date | — |
| Expiry date | Dec 5, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/0816
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic overload relay has an intrinsic power supply connected in parallel with the NC contact of the relay between wire attachment terminals. The power supply is a parallel connected zener diode and capacitor, connected to the processor in parallel with a low voltage sensing circuit that detects the charge on the capacitor, whereby the processor operates to turn on a unijunction transistor for low voltage coil applications to shunt the power supply during contactor closing and turn off a predetermined interval later by which time the contactor should have closed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.