Pool pump fail safe switch
US5172089A · kind A · utility
Inventors
Key dates
| Filing date | Jun 14, 1991 |
| Grant date | Dec 15, 1992 |
| Priority date | — |
| Expiry date | Jun 14, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H36/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fluid detection device designed to detect the presence of fluids in a flowing or non-flowing state and having the ability to energize or de-energize large current devices such as a swimming pool pump motor. It is equipped with a fluid detector tube designed to be mounted to a vertical fluid carrying conduit such as an intake to a pump. The fluid detector tube has an internal float with permanent magnet and a normally open magnetic reed switch mounted to its exterior. The float with permanent magnet at its highest vertical position closes the magnetic reed switch's contacts and activates a phase shift network. The current through the reed switch is less than fifteen millamps. The phase shift network forward biases a diac which in turn forward biases a traic. The traic completes the connection from a power source to a large current device. The de-energize state of the traic is stabilized by a snubber network. The energize state of the traic is stabilized by the phase shift network and diac. Which permits the voltage drop across the traic main terminals to be less than 1.5 vac when operating a large current device at 15 amperes and 120 vac.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.