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Automatically Controlled Air Cooling System for Small Machines

IP.com Disclosure Number: IPCOM000048354D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Falda, A: AUTHOR [+2]

Abstract

For small machines such as modems, air cooling is an important e parameter from both the human factors and technical reliability points of view.

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Automatically Controlled Air Cooling System for Small Machines

For small machines such as modems, air cooling is an important e parameter from both the human factors and technical reliability points of view.

Usually, small machines for which forced cooling is mandatory operate in two modes: 1. Continuous forced cooling.

2. Discontinuous forced cooling.

With continuous forced cooling, the fan is powered simultaneously with the machine and runs continuously until the machine is turned off. In this case, the cooling is sized for the worst-case temperature conditions. As a result, most of the machines are overcooled.

With discontinuous forced cooling, the fan is powered by means of a thermal contact device when the inside temperature reaches a given value.

Thus, in both cases the cooling exceeds the actual requirement, and is an important source of undesired acoustical noise.

It is important to decrease the acoustical noise and improve the reliability of the fan which greatly affects overall machine reliability and the final cost, as well.

All these objectives will be met with the forced cooling system (described hereafter) which allows the inside temperature to be stabilized by controlling the fan speed, the system being mainly characterized in that the fan is used at low speed.

The automatically controlled air cooling system is schematically depicted in the figure. The control circuit comprises a DC amplifier combined with a voltage reference circuit and a comparator (all of which may b...