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HUX
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Join Date: Jan 2007
Location: UK S.Northants
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Good Answers: 19

DC Fan MTTF and RPM

01/30/2012 4:52 AM

Hi, I wonder does anyone have a formula (and its source) for calculating the improvement to be had by reducing the RPM of a DC fan (via PWM for example) some data sheets say "significant" improvements can be achieved but I can't find out how to calculate this.
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Tornado
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Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
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#1

Re: DC fan MTTF and RPM

01/30/2012 4:55 AM

A reasonable starting assumption might be that the motor's life is so many revolutions. On that basis, life would be inversely proportional to rpm. Then just compute from there.

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HUX
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Join Date: Jan 2007
Location: UK S.Northants
Posts: 485
Good Answers: 19
#2
In reply to #1

Re: DC fan MTTF and RPM

01/30/2012 5:51 AM

Thanks, if I had to guess I would have said if you halve the speed you double the life, but describing it like this explains that and makes sense. (I realize there will be a rate at which lubricant is lost which would complicate it slightly, but I'm happy with this).

Thanks.
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TonyS
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United Kingdom - Member - New Member

Join Date: Aug 2010
Location: Resting under the Major Oak
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#3

Re: DC Fan MTTF and RPM

01/30/2012 2:56 PM

You have to consider the loss of cooling airflow through the motor at low speeds

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muditmah
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Join Date: May 2011
Posts: 84
Good Answers: 1
#4

Re: DC Fan MTTF and RPM

02/08/2012 2:49 AM

search "power saving with VFD"

lots and lots of articles on internet on this..
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