Strictly Linear PSU's

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sureshot
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Re: Strictly Linear PSU's

Post by sureshot » 22 Apr 2018, 23:05

Got side tracked with the graphics card heatsink boards...
Wasn't going to post this, but might interest someone.
Needing a variable testing power supply, it's something in progress. I don't have milling machines or cnc etc.
Have to make do. Will be TO220 lm317, or similar, there MJ2955 and MJ11015 transistors.
Yes the holes for the screws are blind, so isolation seems to be fine that side of the screw. Other holes for regulator, and large centre holes for transistor wires to loop back through. A mm or so off on one hole, it's only feeding wire back through so not critical.
Regulator heatsinks are one side cut off to fit the board. Makes a small package 100 watt or there abouts unit.
Hopefully get an enclosure and meters this time, I'll only end up using one of those in the picture, undecided which yet.
Drilling cutting tapping does take time, precision is not easy with out machine shop tools.
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radio pete
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Re: Strictly Linear PSU's

Post by radio pete » 23 Apr 2018, 10:06

Nice work neat job

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Re: Strictly Linear PSU's

Post by sureshot » 23 Apr 2018, 18:21

radio pete wrote:
23 Apr 2018, 10:06
Nice work neat job
Cheers Pete :)
Anyone else doing anything interesting with linear power ? Post it up if you have. :)
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Re: Strictly Linear PSU's

Post by sureshot » 27 Apr 2018, 23:02

Tiny bit more progress, can't believe it would take so long to mount 4x transistors, solder and heatshrink.
A few years ago I stumbled on a Watson power supply, sadly it had been driven to death. Anyway the two output transistors had been factory mounted with nylon machine screws.
One had partially melted and lost contact with the heatsink.
I have been thinking of giving nylon a go for a while, but added some red loctite to each fastner for a bit more insurance on heat stability.
As long as the heatsink is under 80°C it should hold up. I'm curious to see if nylon holds up.
Through the centre of the heatsinks are the base and emitter leads. Collector off the cases.
Can see the wrap through from behind the heatsinks. Fans to refit.
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Re: Strictly Linear PSU's

Post by stanogs68 » 27 Apr 2018, 23:35

thats top work ,brilliant
computers mess with my brain !

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Re: Strictly Linear PSU's

Post by sureshot » 28 Apr 2018, 10:26

stanogs68 wrote:
27 Apr 2018, 23:35
thats top work ,brilliant
Thanks pal, they don't look much at this stage. The unique attraction is the small foot print for power size. The boards are 100x150mm For a power rating of 100 watts or close to it, that's not a bad footprint at all. It can be scalled up, more of the same cpu heatsinks for greater power handling capabilities.
Its a slow process unfortunately for me, but i will try and see it through to an end usable unit.
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