Re: [Phys-l] glassware needed

[Bernard Cleyet <bernardcleyet@redshift.com>]

>  they suffer just the same
>   deficit as the style of meter that loses narrow power consumption  
> spikes of
>   naive experimenters - it's still a bandwidth issue.

You certain about that?

I thought, well maybe the inertia of wheel and armature absorbs the  
pulse and because of the very low source impedance there's no "over  
shoot", so the  spike will be ignored.  Then I thought of the  
ballistic galvo. wherein the spike (e.g. discharging cap.) is over  
before the armature moves.  OTOH the BG is shunted by a CDRX not way  
over damped (milliOhms).  To test this at some point I'll drive one  
of my d 'Arsonval wattmeters (light bulb loaded) w/ an amp driven by  
a pulse generator, and a filament transformer for Z matching.   
O'scope observation, natürlich.

No that's not exactly the case, hell, use the triac lamp dimmer and  
o'scope.

bc can't wait, but already convinced.


> Variacs are helpful for maintaining power waveforms - but they  
> don't come
> cheap.

p.s. Mark K.  found two and gave me one at the San Francisco City  
College surplus give away a few weeks ago.  At one time RAFT had a  
few for a few $$ ea.



On 2009, Jan 01, , at 19:42, Brian Whatcott wrote:

> Sad to tell, though spinning disk watt-hour meters of the kind used  
> to meter
>   domestic consumption are required to register within 4% at low loads
>   and 3% at higher, even inductive loads - they suffer just the same
>   deficit as the style of meter that loses narrow power consumption  
> spikes of
>   naive experimenters - it's still a bandwidth issue.
>
> Variacs are helpful for maintaining power waveforms - but they  
> don't come
> cheap.
>
> BrianW
>
> At 09:20 PM 1/1/2009, you wrote:
> > This allows me to advertise my collection of aquarium heaters for
> > very little $. ... Aren't variable auto transformers (Variac) in  
> > plentiful
> > supply? AND  at one time (now too?) watt-hour meters were offered by
> > surplus houses.  Since they operate on the principle of one part of
> > the motor sensing the potential and the other the current, no problem
> > w/ PF.
>
> ....
> Brian Whatcott    Altus OK    Eureka!
>
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