On 11-19-97 Roy J. Tellason wrote to all... 
 
 RJ> I was browsing this catalog offering inverters,  and saw  
 RJ> mention in there that some stuff will run on just about any  
 RJ> type,  some stuff wants a modified sine wave at least,  and  
 RJ> some wants a "pure" sine wave.  I can't find the reference  
 RJ> in that catalog at the moment. 
 RJ>  
 RJ> Can somebody run down what sort of stuff is fussy about its  
 RJ> power,  and perhaps why?  Some of the things on that list  
 RJ> were rather surprising... 
Lemmee know whatcha find Roy.  I had a brand new BJ cannon that 
immediately *fried* when run on a sin wave inverter. seven weeks 
later, the replacement fried just as fast.  Researching the 
cause, I found an article in Electronic Engineering Times from 
some German researchers about disasters with PFC computer power 
supplies.  It seems that the PFCs sample the AC sign wave in the 
same manner that sin wave inverters and switch mode power supply 
designs used in printers, and god nose what else. 
 
When several PFC devices are on a given AC bus, each will pick up 
on a random spike in the line, and in each trying to damp it, all 
at the same time, the feedback over-responds, and catastrophic 
surges have been bounced back to the nearest transformer, which 
shorts out, and the Germans found a lotta fires. 
 
What is more, neither the utility equipment manufacturers would 
admit to any culpability, nor would any of the PFC manufacturers. 
Naturally, the law suits would be considerable. ;}  And, any new 
design changes would be evidence of original defect. 
 
So, such a list as you propose, would not be a popular item with 
the electronic equipment manufacturers and vendors. 
 
SO: I for one, would not use any inverter at all on any device with 
a switch mode power supply; the feedback overload may not appear 
initially, nor soon, but *can* at any time.  Lacking a choice, If 
I had to use one, I would employ an isolation transformer, the 
bigger the better, hoping the hysteresis would be sufficient to 
damp the resonant harmonics that otherwise break into feedback, 
much as a high school gym PA breaks into a squeeeeel. 
___ 
 * OFFLINE 1.58 * You finally know what women want- you aint got it anymore. 
--- Maximus 3.01
---------------