2 Secondaries@45ACV....Filter Caps 75V Rating

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FBJ

Member
2002-03-12 7:46 am
USA
Hey can someone give an idea if I can used a transformer with secondaries of 45 acv with filter caps of 75vdc with surge of 84vdc. The caps are of good quailty. Newark as the caps for about $40.00ea. I only got two caps and I would like to use them since they were give to me. I had use the transformer for testing a amp before and if I remember right the variac turned up all the way to 120 vac gave secondaries output of 65 vdc. Any help??:confused:
 
Here's a rough estimate.
45vac x 1.414 - 0.7v = 62.9vdc
Also, you might want to consider the regulation factor of the transformer(might be as high as 15%), as the 45vac rating is most likely a fully-loaded rating. And I think it's a good idea to over-rate the caps by at least 20%.
69.2vdc + 20% = 75.5vdc
All told, the 75vdc caps should be fine. Using those would satisfy me(and I'm pretty cautious about ratings), but you might want to get a second opinion if you have any doubts.
 

FBJ

Member
2002-03-12 7:46 am
USA
Thanks guys for posting replies back quick.

But I forgot to mention that when I was doing tests with the transformer while using the Variac at 120 Vac I was using 100 Vdc filter caps driving an amplifier output stage of 4 mosfets per channel. An that how I plan to use the transformer again with the same amount of ouput transistors. So I measured the ACV from the wall and it's 112-117 VAC and I should be alright then.
Thanks again.
:D
 
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