Reefer Vent fan

[hdavis]

>GMCers
>
>Some time back I mentioned the idea of putting a computer fan
>in the vent over the reefer. Some concern was expressed about
>the heat it would be exposed to. So I thought I had better do some
>more research. The Tech America fan #900-2514 has a design
>temperature range of-22 to 170 degrees F. They are ball bearing
>fans not the bronze sleeve type.

Arch,

you might want to ask them for the MTBF for the fan at various temps. I
consulted to a company that makes CPU fans and know from that experience
that different fan manufacturers have vastly different MTBFs. From what I
saw of actual failure rates, a good sealed ball bearing fan will
significantly outlast a sleeved fan.

Henry

Henry Davis Consulting, Inc / new product consulting
PO Box 1270 / product readiness reviews
Soquel, Ca 95073 / IP reviews
ph: (831) 462-5199 / full service marketing
fax: (831) 462-5198
http://www.henry-davis.com/ http://www.henry-davis.com

 

[chuck blanford]

>What is a MTBF?
>
>Take Care
>Arch

Arch

I believe it is an acronym for Mean Time Before Failure.

Chuck
77 Kingsley
North Idaho

 

[hdavis]

>In a message dated 9/8/99 9:37:46 PM Central Daylight Time,

>
>>
>> you might want to ask them for the MTBF for the fan at various temps. I
>> consulted to a company that makes CPU fans and know from that experience
>
>Henry
>
>What is a MTBF?

Mean TIme Between Failures

It gives you an idea of how long you should expect the part to last under
specific conditions. Since it's "Mean Time", there's a distribution of
failures to be expected over time. Some will fail "early" under the same
conditions as others will fail "late."

In the early to mid 1980s many of the electronics divisions of car
companies that I worked with had a design goal of 2000 power on engine
hours before major repair. That meant that if you sat in a parkling lot for
2000 hours running your engine there should be no major failure. Likewise,
if you charged down the road at 55 MPH for 2000 hours there should also be
no major repairs. Bottom line for this goal was that individual components
had to have failure rates much lower than the 2000 hour mark. The reason
has to do with the probability of failure of the assembled product being
determined by the sum of the individual components. Each individual
component had its own failure rate which was combined with all of the other
failure rates in the product to determine the expected life (or failure
rate) of the whole product.

BTW, this emphasis on 2000 power on engine hours led many engineering
groups to adopt a design methodology that optimized parts to last 2000
hours with significant failures past that point.

Henry

Henry
Henry Davis Consulting, Inc / new product consulting
PO Box 1270 / product readiness reviews
Soquel, Ca 95073 / IP reviews
ph: (831) 462-5199 / full service marketing
fax: (831) 462-5198
http://www.henry-davis.com/ http://www.henry-davis.com