wrote:


I need to power an amp that draws just under 1.5 amps at 110 volts.
I measured the current it draws when powered from my variac. The
voltage to the amp should be within 5% according to the documentation.
The voltage in my house measures 122 volts to 126 volts, varying
during the day. So bucking 12 volts should be fine.
I am looking at a 120 volt to 12 volt center tapped 5 amp rated
xmfr at PartsExpress. The VA of the xmfr is not listed in the
description. I want to connect this xmfr in buck configuration. Since
I will be bucking 12 volts at approx 1.5 amps this equals 18 VA. At
least that's how I remember how to calculate VA from connecting big
buck xmfrs to one of my machines several years ago. I think the 12
volts at 5 amps secondary means that the xmfr is 60 VA. But I'm not
sure because it is center tapped. It shouldn't make any difference,
right? If I used the center tap and just bucked 6 volts then the VA
rating would be 30, wouldn't it?


** You need to buck 1.5 amps and you have a tranny rated to do 5 amps.

Whether you use the whole or only half the 12V secondary is up to you.



..... Phil