Re: [Amps] 50 or 60 Hz, a problem?

[R.Measures <r@somis.org>]

On Jan 10, 2005, at 11:51 PM, Steve Thompson wrote:

> Will Matney wrote:
> > Bob,
> >
> > That settles it then, I'd say Heath built about everything with 50 Hz
> > transformers, or at least after a certain year I imagine.
>
> In amps where it matters (probably those with external anode tubes 
> rather
> than Heath stuff), beware of blower ratings. The loss of pressure and
> airflow at 50Hz instead of 60Hz can be significant if the cooling 
> capacity
> is marginal.

The speed of the shaded-pole, current-limiting fan motor in a SB-220 is 
largely a function of air-resistance to the fan blade.  Hence, a 
SB220's fan blade spins faster in 12,000ft high, 50Hz La Paz than it 
does in sea-level 60Hz Boston.  And, as a result, the CFM is 
semi-constant with changes in air-density.  As I see it, the SB-220's 
design is simple, yet sophisticated.

cheers, Steve
> Steve
>
>
>
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org

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