At 19:53 11/3/97 +0200, you wrote:
>Hi Rich, Peter and all,
>
>Concerning blower performance, this is what I found in an excellent
>article by G8WRB in October QEX:
>
>Free air-flow rate is proportional to N (rpm), therefore proportional
>with f (Hz)
>Cutoff back pressure is proportional to N square
============================================
Flow volume is proportional to thr speed change ratio N1/N2.
Pressure is proportional to the speed change ratio squared.
The actual Horsepower load on the blower motor is proportional to the
speed change cubed power.
And yes, you are correct, speed change is a function of frequency and
motor poles in the winding.
>I'm familiar with the problem reported by the SM amateur. I encountered
>the same with a MLA2500 from USA, but with a twist: in addition to
>reduced plate voltage (due to 220V versus 240V mains and no primary
>taps), the main transformer runs pretty hot, even on standby.
=============================================>
50 Hertz speed makes the transformer less efficient, therefore more
power is generated within,
in the the form of heat.
73,
N5RP
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|