[R-390] line filter for EAC R390A

[Roy Morgan]

On Jul 27, 2009, at 11:27 PM, Barry wrote:

> Mouser stocks these:
>
> http://www.evoxrifa.com/cap_catalog/emisuppr/pme271y.pdf
>
> However, they're only stocked in the 250V version.  I'm curious if the
> equipment were to be run on 220VAC, if this would be sufficient  
> rating.

Barry,

Line filter/bypass caps are SERIOUSLY under rated. They are safety  
items and cost a bit more because of it.  You can be assured that the  
cap rated at 250 VAC will run just fine forever at 220 Volts line  
voltage.

I remember a tale told by an audio amp builder. He had some motor  
start capacitors rated at 440 volts AC and talked to an engineer at  
the manufacturer about whether he could run them at 550 or 600 volts  
DC safely. The engineer laughed, and said that they are all tested at  
some four times that and he can expect the caps to not fail, period.

Do check the facts on this, but I think the line safety caps are of  
the "self healing" metal film type in that if they do short in a local  
area, the conducting part of the film burns away and leaves an open  
circuit.

The justradios.com web site has further information about this, I seem  
to remember. They also offer dual-rated disk ceramic caps - the self  
healing aspects may not apply to them.

Roy

Roy Morgan
k1lky at earthlink.net
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Groton NY, 13073
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