I have acquired a Henry 2K Classic X (domestic model) amplifier. It uses a
pair of 3-500Z's with chimneys. The very loud Dayton blower is driving me nuts.
The Dayton blower is a model 2C915A, 3020 RPM, 230 volts and 140 CFM. This same
blower is used when the larger Plate transformer of the Export model is
installed. I suspect that this blower is much larger than required when
operating at 1500 watts on CW or SSB.
The standard blower in the 2K Classic was a Redmond 80239, 110vac unit. I
cannot find the specs but I suspect it was around 90 CFM.
I have researched several articles on about using a pair of 3-500Z's and the
reference material shows a need for about 13 cfm per tube or 26 cfm total.
Likewise, a 3-1000Z requires 4 cfm. I am aware that back pressure requirements
play into this also.
I read somewhere that it is possible to slow down a blower during standby
periods by using a "split-capacitor" motor. Perhaps I have the phraseology
wrong, but what I would like to do is have a blower slow down in speed
significantly during listening periods and come up to speed during TX. I
operate mostly CW, little SSB, and do not use break-in/QSK so I could switch
relays to do this.
My other alternative is to install a smaller blower and risk shortening tube
life. I do not contest very much nor operate continuous modes such as RTTY and
FT8 at full power.
Your ideas are welcome!
73, Dennis W0JX
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