Multiple fan having means for reducing beat frequency oscillations
AssigneeDell USA, L.P.
InventorsKeith Alan Lyszkowski, Douglas E. Wallace, Jr.
Life of this patent
Estimating the term…
Abstract
A multiple fan system including at least two simultaneously operated fans. Each of the fans are operable as a constant speed fan and as an oscillating speed fan. Not more than one of the fans is operated as a constant speed fan. Each fan not being operated as a constant speed fan is operated as an oscillating speed fan. A fan controller operates each oscillating speed fan in a mode whereby a respective acoustic emission having a range of frequency different than any other oscillating speed fans is produced.
Claims9
A multiple fan system, comprising
- at least two simultaneously operated fans, each fan being capable of operating as a constant speed fan or as an oscillating speed fan, only one of the fans being operated as a constant speed fan, each other fan being operated as an oscillating speed fan;
- and
- one fan controller capable of controlling a plurality of oscillating speed fans for controlling a plurality of the oscillating speed fans within a different range of speed from each other oscillating speed fan, the means for controlling providing an output voltage having a varying duty cycle and providing an oscillating fan speed profile having an oscillating speed range.
A multiple fan system, comprising:
- at least two simultaneously operated fans, each fan being capable of operating as a constant speed fan or as an oscillating speed fan, only one of the fans being operated as a constant speed fan, each other fan being operated as an oscillating speed fan;
- and
- one fan controller capable of controlling a plurality of oscillating speed fans connected to each of the oscillating speed fans, the fan controller operating each fan to produce a respective acoustic emission having a range of frequency different than each of the other oscillating speed fans, and the fan controller providing an output voltage having a varying duty cycle and providing an oscillating fan speed profile having an oscillating speed range.
A multiple fan system, comprising:
- a constant speed fan;
- at least one oscillating speed fans operated simultaneously with the constant speed fan;
- and
- one fan controller capable of controlling a plurality of oscillating speed fans operating each of the oscillating speed fans within a different range of speed from each other oscillating speed fan, the fan controller providing an output voltage having a varying duty cycle and providing an oscillating fan speed profile having an oscillating speed range, the fan controller further including a waveform generating portion coupled to a duty-cycle modulator portion.
Dependencies are inferred from the claim text.