Browse Prior Art Database

Flexible Cooling Fan Control

IP.com Disclosure Number: IPCOM000108144D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 71K

Publishing Venue

IBM

Related People

Bistline, WR: AUTHOR [+3]

Abstract

Disclosed is a method to allow the optimal fan speed to be selected in a machine to match the cooling requirements of the feature cards and device options. A product's acoustic emissions are generally in direct proportion to the cooling fans' rotational speeds. The method described here permits the fan speeds with proportional acoustic noise to be changed by the operator or serviceperson for the specific machine configuration and therefore keep the fan-induced noise at a lower level.

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This is the abbreviated version, containing approximately 100% of the total text.

Flexible Cooling Fan Control

      Disclosed is a method to allow the optimal fan speed to be
selected in a machine to match the cooling requirements of the
feature cards and device options.  A product's acoustic emissions are
generally in direct proportion to the cooling fans' rotational
speeds. The method described here permits the fan speeds with
proportional acoustic noise to be changed by the operator or
serviceperson for the specific machine configuration and therefore
keep the fan-induced noise at a lower level.

      The circuit shown in the figure is employed for each fan in the
machine to control the fan speed and, therefore, air flow, in each of
the compartments of the product. Only one switch is closed to select
the DC voltage to the fan. S1 is closed for maximum voltage and
therefore maximum fan speed and cooling.  Switches S2 - S5 select
progressively lower voltages as resistors R1 - R4 provide for
increasing resistance to provide the voltage drops.

      The appropriate switch settings for each feature mix are
defined in the operator's manual or setup instructions for each
machine.  This allows the operator or serviceperson to set the
optimum fan speeds for the specific machine configuration.

      Disclosed anonymously.