madmark1
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50 amp home made supply
this is my main supply, its fixed at 13.8v runs peak at 50 amps, its current limited with soft start and crowbar overvoltage, took a few weeks to build, its been up and running without any problems for more than 4 years now....fingers crossed.
http://i925.photobucket.com/albums/ad100/madmark42/powersupplyinternals.jpg
Last edited by madmark1, 1/Nov/2009, 2:48 pm
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1/Nov/2009, 2:28 pm
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26FB332
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Re: 50 amp home made supply
I like that, Is Heat and coolin a problem?
---
Yaesu FT-847. MD-100 Mike. MA5B beam. Yaesu G-250. MFJ-929 Intellituner. SP-8
26SW766. The Shiner.
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2/Nov/2009, 6:18 pm
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madmark1
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Re: 50 amp home made supply
hi shiner, no heat isnt a problem at all, when i built the supply i added a fan to the rear heat sink but it really isnt needed at all for ssb use, the supply is 17 inch long, 10 inch wide and 8 inch high, so its not really to big... the main voltage control board came from a 3 amp cb type supply, thats the board closest to you in the photo, just behind that is the crowbar circuit this is home etched and made using a mc3423 overvoltage ic, this monitors the voltage ive set it at 14.0 volts this fires an 14.0 volts this inturn triggers a thyristor that triggers the main relay in the photo and disconnects the mains, at the same time the main capacitor is discharged through a resistor bank on the board that empties the main capacitor, its a copy of the marchwood..sort of.
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2/Nov/2009, 7:20 pm
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Hot Fusion
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Re: 50 amp home made supply
Nice one. I think I'd have simplified the overvoltage bit to a zener feeding a thyristor fed from the unregulated supply, operating the relay to open the contacts, breaking the circuit between the electrolytic and the regulator circuitry - this is what I'm planning for mine.
The only issue with this seems to be finding a relay with hefty enough contacts on the N/O side to carry the current. Hmmm...
Anyhow, good to see there are still avid constructors out there!
Last edited by Hot Fusion, 2/Nov/2009, 8:44 pm
---
Andy - 26 FB107
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2/Nov/2009, 8:42 pm
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madmark1
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Re: 50 amp home made supply
hi andy, theres lots of different ways to use a crowbar circuit, but ive used this circuit in other supplies and its always worked without any problems..... so ive used it again, best stick with what works for you , or so ive found.......next project on the supply is twin digital meters one for volts and one for amps, this may be my winter project, after the completion of my rebuild of my FL-2100B. 163trc20
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2/Nov/2009, 10:26 pm
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Steve 94
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Re: 50 amp home made supply
Nice job Marc, my PSU is very similar to yours, built by a company called Merlin systems back in the early 90's, who are no longer in business, belt and braises job built to last.
Have you heard of this company before?, every body I have ever spoken to has never seen or heard of them.
Steve
30FB007.
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9/Nov/2009, 9:57 pm
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madmark1
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Re: 50 amp home made supply
hi steve, sure i know merlin, they used to be based in somerset, they made the wizard psu, ive a brand new toroid transformer for the wizard psu, i bought it years ago now.....was going to make yet another supply, maybe i will next year, i hope to make a few more mods to the supply in the next few months......lcd meters 'maybe' ....temp switched fan control definatlly, and maybe just uprate the wiring abit, the transformer is rated at 50 amps the cable though is about 30 amps, i do get abit of voltage drop, 13.8 drops to 13.6 at 30 amps. not bad though.
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11/Nov/2009, 8:29 pm
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simo276
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Re: 50 amp home made supply
Hey just wondering where you got the transformer from , if i could get one i would consider makink onw with a varible output also
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21/Nov/2009, 2:40 pm
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madmark1
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Re: 50 amp home made supply
the transformer came from a radio rally a few years ago, i know that it would be very expensive to buy new at todays prices.
regards from mark 163fb20.
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22/Nov/2009, 4:06 pm
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