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Old 13th October 2003, 12:02 PM   #1
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Default PSU capacitor max.voltage question

Hello,

Is it safe to use 400v rated capacitors in PSU like below??? - according to my knowledge the maximum voltage on caps will be less than 360V.

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Old 13th October 2003, 12:24 PM   #2
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I don't have data of this power transformer but secondary for B+ are at about 250-260V.

Any help?
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Old 13th October 2003, 12:41 PM   #3
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Hi,

Assuming a 0-260VAC secundary you'll be perfectly safe.


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Old 13th October 2003, 12:43 PM   #4
Jennice is offline Jennice  Denmark
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Hi...

I've never worked with tupe audio, but as I see it, there's a potential risk for the capacítor located between the bridge rectifier and the inductor. Ripple voltage peaks will be much higher there than after the inductor. Just a consideration. Maybe a computer simulation could solve the mystery.

anyone up for the task?

Jennice.
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Old 13th October 2003, 01:06 PM   #5
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So maybe the good solution is to have 450V rated cap before choke and after the choke - 400V rated caps?

Thx. for answers....
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Old 13th October 2003, 02:23 PM   #6
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Quote:
Originally posted by Jennice
I've never worked with tupe audio, but as I see it, there's a potential risk for the capacítor located between the bridge rectifier and the inductor. Ripple voltage peaks will be much higher there than after the inductor. Just a consideration. Maybe a computer simulation could solve the mystery.
Is this only an idea or have you practical experience of it?
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Old 14th October 2003, 12:31 AM   #7
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Hi,

Quote:
Is this only an idea or have you practical experience of it?
I'd suggest you guys fight Viking batlles outside the classroom/forum?

Per-Anders, I know what you mean, but do we have to bite other people's head of?

Please?
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Old 14th October 2003, 12:37 AM   #8
badman is offline badman  United States
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Default cap voltage

Electrolytic capacitors operate best close to their rated voltage. If B+ is no more than 250-260, then 300V caps would be appropo, and perform better than 400-450V caps. If you're worried about post rectifier ripple, use a HV poly after the rectifier, and electrolytics after the inductors.
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Old 14th October 2003, 12:50 AM   #9
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Hi,

Quote:
Electrolytic capacitors operate best close to their rated voltage.
Yes...But what about safety margins?

Now do your sims at what cap values really are at operating voltages and feel as smug as you think you are.

Feeling kinda Freddish,
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Old 14th October 2003, 04:23 AM   #10
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Don't forget that caps are rated for a good bit of overvoltage too. And I personally have ran a 350V rated cap (60s-era octal based, no less) at 450V with no ill effects

*Don't do that on purpose BTW*

Tim
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