Re: [pvusers] The Exceltech Pure Sine waveform is really good

["Scott Willing" <willing@mb.sympatico.ca>]

On 19 Jul 2002 at 18:59, John D'Angelo wrote:

> on 7/19/02 18:10, Scott Willing at willing@mb.sympatico.ca wrote:
> 
> > What kind of acoustic noise do they make? Right off the unit, I mean
> > - hmm, buzz, sizzle? Silence plus fan noise?
> 
> They are virtuialy SILENT unlike the transformer based Trace inverters
> which emmit a constant low level buzz. There is a fan on all the
> Excetech inverters that only turn on when the unit is providing power
> for long periods of peak output. The fans are like those used on
> computers. Very quit.

Great.
 
> The switching is done by transistors which are silent to the human
> ear.

Yeah, I've built a few inverters in my day so I understand the concept. 
Oddly, MOSFET's do make quite a bit of noise when you get outside 
their SOA (safe operating area) and they explode. :-)

It's the magnetics that tend to make racket. I even have a high-
frequency switch-mode battery charger (no 60Hz magnetics) that 
makes a bit of frying noise. Sort of unsettling, actually, but seems to be 
normal for this unit.

> Another thing I love about the Exceltech is the 1 K modules
> weight about 7 pounds!
 
Obviously no 60Hz magnetics.

As for your other comment vis-a-vis quality / price, yes, true, I was 
speaking in relative terms. I believe (but don't know) that Etech is more 
expensive/watt than Trace or Statpower machines, neither of which are 
exactly Wallmart-grade hardware either. :-)

-=s



--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*
  List sponsored by CREST/REPP  
	http://solstice.crest.org/   http://www.repp.org/