Hardware Analysis Community Forums http://www.hardwareanalysis.com/content/topic/2888/ 2008-12-03T15:58:55-05:00 http://www.hardwareanalysis.com/content/topic/2888/ http://media.hardwareanalysis.com/halogo.gif text/html 2002-10-03T17:26:58-05:00 Sander Sassen http://www.hardwareanalysis.com/content/topic/2888/#14199 Okay, that's indeed about accurate. But there's more to it, as the platters spin they do heat up, both from the heat dissipated from the motor as well as the friction with the air. The point I wanted to make is that the air does not cool them, eventhough the rpm is that high. The air is trapped inside the casing and thus the platters get substantially hotter then if they were operating in the open air, which of course is not an option as the platters would become contaminated with dust particles and what not.<br /> <br /> Kind regards,<br /> text/html 2002-10-03T16:26:23-05:00 Mike Asher http://www.hardwareanalysis.com/content/topic/2888/#14190 A 3.5&quot;, single platter 7200 rpm drive has ~19 sq. inches of platter moving at a linear velocity ranging from 0 to 110 ft/sec. Even a pessimistic assumption for the coefficient of friction on that platter gives a heat output on the order of a 10-100 milliwatts. As drives of this type have a power consumption on the order of 10 watts- and all of that electrical power is converted into heat- the amount of heat generated from air friction is less than 1% of total.<br /> <br /> Resistive heating of the spindle windings and internal spindle friction is by far the largest component of the heat generation. Second is heat generated by the internal circuitry.<br /> text/html 2002-10-03T15:33:56-05:00 Sander Sassen http://www.hardwareanalysis.com/content/topic/2888/#14179 Mike, <br /> <br /> I think you then should be getting in touch with a number of harddisk manufacturers as they must've made an error in the design somewhere.<br /> <br /> Kind regards,<br /> text/html 2002-10-03T14:37:09-05:00 Mike Asher http://www.hardwareanalysis.com/content/topic/2888/#0 &lt;i&gt;as the spinning platters get hot due to the friction with the surrounding air...&lt;/i&gt;<br /> <br /> Jeje...hard discs don't heat up from air friction..they heat up from power dissipation, primarily the power consumed by the spindle motor.