Railroad track circuit vital relay control
US5737173A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1996 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | Jun 3, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A railroad vital relay control circuit has a first input for receiving a reference alternating current signal of a selected frequency and a second input for receiving a track alternating current signal having the selected frequency of the reference signal and a predetermined phase and magnitude relationship therewith. A magnetic core provides a logical AND function and has two input arms and an intermediate output arm. There is a winding on each of the input arms and a winding on the output arm. There are frequency tuned voltage limiting circuit elements connecting the first input and a first one of the magnetic core input windings and the second input and the second input winding of the magnetic core. The magnetic core has an output winding on the intermediate arm which is connected to a vital relay. The input windings on the magnetic core are connected to produce flux in the same direction in the output arm. In phase signals of the selected frequency at the magnetic core input windings provide sufficient flux in the output arm to induce a signal in the output winding to hold the vital relay in an operated position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.