>Richard wrote:
>>
>>
>>>Richard wrote:
>>>>>I need to know how to determine if the following fans will be adequate
>>>>>for an 4cx1000/1500 amp. While I can find the cfm specs, I cannot
>>>>>find the back pressure specs.
>>>>
>>>>Ordinary fans do not create enough air pressure to cool external anode
>>>>tubes. A centrifugal blower makes more pressure. I like to mount the
>>>>tube/socket in a cardboard box and measure air pressure with a
>>>>manometer.
>>>>
>>>>
>>>Agreed about the cardboard box mock-up, just to see if the blower is big
>>>enough.
>>>
>>>Broadening the answer, it is better to measure the cfm directly by
>>>letting the exhaust air blow up a thin plastic bag, and timing how long
>>>it takes (as recommended here by K6GT).
>>
>>?Ǩ Eimac provides a number of pressure vs cfm points in their spec sheets.
>>
>These pressure figures only relate to the one particular method of
>blowing: upward through the socket, chimney and anode cooler in series.
? for some tubes, air is specified as blown from cathode to anode.
.
>For other methods of blowing, the pressure drops will be different so
>you have to work directly from the cfm specification - remembering that
>it's cfm, not pressure, that actually cools the tube (well, OK, strictly
>speaking it's the mass flow rate, not the volume).
>
>--
>73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
> 'In Practice' columnist for RadCom (RSGB)
> http://www.ifwtech.com/g3sek
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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