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HV power supply capacitors

PostPosted: Mon Aug 19, 2013 10:04 pm
by RidgeRunner
I'm looking for capacitors for my high voltage power supply. I need about 50,000-80,000 MFD rated somewhere around 160-200 volts. I've been checking around new, but wondering if anyone has a stash around for sale. NEAR-fest is coming up too so I'm hopeful something comes up there too.

Thank you

Re: HV power supply capacitors

PostPosted: Tue Aug 20, 2013 12:17 am
by kf1z
Must be for a Class-H modulator maybe?
Wouldn't need that much for PWM...

I have 6 or 8 ( thinking 6) of those HUGE telco caps.
I think they are 75v @ 30,000uF
All 6 in series/parrallel would do it, but take a LOT of space. :-)

They are like 3" diameter and 8" tall!

Unless you find a real deal on something, you're probably going to find the
2,200uF @160 or 200v the best buy.
Even though you'd have to string a passel of them in parallel to get the capacity you want.

Ebay: ... 35cacbf909

Those are 160v, 3,300uF at $8 each.... not bad compared to the US suppliers

Big caps aren't cheap!

Re: HV power supply capacitors

PostPosted: Tue Aug 20, 2013 10:57 am
by RidgeRunner
I plan on building a 24 FET xmitter and plan on going PWM. From talking with Steve (QIX) he suggested about 48000 MFD and I've talked to other people running up to 80000 MFD so I just put a range. I'm not totally sure so I am going off the suggestions of others.

After looking at that link you posted those 4700 MFD caps could work I would have to get like 10 or 11 to get into that range I'm looking for.

Re: HV power supply capacitors

PostPosted: Wed Aug 21, 2013 12:11 am
by kf1z
If you're going with Steve's PWM generator board, 48000uF is more than enough. ( that's how Steve is. :-) )
It has a feed-foreward circuit that will pretty much eliminate any PS ripple with careful adjustment.

of course, with a transmitter putting out 1200 watts carrier, and between 4800 to 6000 watts pep... maybe a little
extra capacity is a good idea :lol:

And yes, you would need multiple caps, but believe me, unless you stumble on a deal, it is the cheapest way to go.
and those types of caps don't take up much room.

Re: HV power supply capacitors

PostPosted: Fri Jan 10, 2014 9:48 am
by steve_qix
I used 20 2200uF 160V capacitors. These types of caps are reasonably available from Ebay and other surplus types of sources. I think I paid something like $1.50 each for them.