Patent · US Expired

Fan operating status sensing circuit

US4977375A · kind A · utility

25Cited by
1References
11Claims
0Family size

Assignee

Inventor

Key dates

Filing dateJan 18, 1989
Grant dateDec 11, 1990
Priority date
Expiry dateJan 18, 2009

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01R19/15
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

A direct current fan's status is monitored electronically using a current monitoring circuit. Normally, when a fan is running it exhibits a pulsating current input. The resulting alternating current signal is monitored via the current monitoring circuit to detect whether the fan is running or not.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.