Electromechanical and solid-state AC relay with reduced arcing
US7660083B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 2007 |
| Grant date | Feb 9, 2010 |
| Priority date | — |
| Expiry date | Aug 5, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H9/542
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electromechanical/solid-state AC relay has an electromechanical winding coil that moves an armature to force mechanical contacts to open or close. Electrical arcing across the mechanical contacts that occur as the contacts are opening or closing can damage and severely reduce the lifetime of the relay. Contact arcing is prevented by pulsing a triac on for a short period of time just before and after the mechanical contacts make or break contact. The triac limits the voltage difference across the mechanical contacts to less than one volt to prevent arcing. The triac is turned off after the mechanical contacts finish moving, reducing the heating and average power through the triac. A zero-sampling circuit that detects when the AC input voltage switches across 0 volts and activates a control integrated circuit to switch on the triac during zero-crossings to minimize power surges.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.