Author Topic: What to do with a 4000 V power supply (plus mini tear-down)  (Read 7078 times)

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Offline SharpEars

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What to do with a 4000 V power supply (plus mini tear-down)
« on: November 22, 2015, 03:53:41 am »
What to do with a 4000 power supply? That's the question I've been asked countless times since I got it.

Well, I've grown tired of having to think of an answer to that question and here is what I am going to use it for, once and for all:

Click on the images for a screenfull...



That's right 4 kV going right into a red LED. Just kidding of course, it is being current limited (CC mode) to a nice warm and cuddly 10 mA. If I really put 4kV into that LED it would probably blow like no LED has been seen blowing before.

For anyone interested in what goes on inside one of these beasties, here is the first pic on the net of the guts of this particular model (electronics porn warning  >:D ):



Yes, everything is big in Texas (and 4 kV power supplies). The mains transformer is the little one on the left side with the 33k resistor across it. You can probably guess what the mother of all power supply transformers in the center does (covered with poured wax too, with little waxcicles that formed on the bottom of it from the pour).

There is a bit of a bodge in there, because I had to replace a 200k 1% (low ppm?) resistor that had gone bad and was screwing up the voltage setting of the hundreds dial:



This is a temporary solution and those aren't just crappy Chinese 1% resistors I soldered in there, they're actually hand picked low ppm resistors (0.1%, +/-15 ppm) that measure almost exactly 200k together (200,005 ohms if my meter is spot on). Unfortunately, together they're only spec'ed at 0.25 W each for a combined 0.5 W load handling ability across the two of them, so I need to replace them with something more substantial. I believe the correct power rating on the rest of the resistors is 1 W, so the search won't be too bad (and the bodge will survive at least for the short term) - I hate entering unobtainium territory with these old supplies. When used properly with a fixed load, there is only about 25 mW flowing through each of them, but I do intend to replace them with the correct part once I place my next order through DigiKey.

Anyways enough of my rant and I hope you've enjoyed this post.

Update:

You came in here expecting more (i.e., sparks flying)? Well, here is what 3.2 kV flying through an air gap of about 1/16" (1.5 mm) of air looks like. It took me about a hundred picture attempts at high speed to capture it well:


« Last Edit: November 23, 2015, 12:37:52 am by SharpEars »
 

Offline Cubdriver

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Re: What to do with a 4,000 V power supply (plus mini tear-down)
« Reply #1 on: November 22, 2015, 06:06:19 am »
Very cool.  I have its 1kV cousin in my pile-o-stuff-to-be-gone-through; bought it cheap on eBuy a few months ago intending to ultimately use it to re-form electrolytics for tube gear - CC/CV settings with a voltage capability higher than anything I'd encounter as a cap would let it run (relatively) unattended - set voltage and current limits, connect cap, turn on and watch things out of the corner of my eye.  It's a PITA doing them on my Sprague TO-4 as I have to keep checking the leakage current and bumping up the voltage as the oxide layer builds and the current drops off. 

It's nice to see pics of the innards; I haven't yet opened mine up.

-Pat 
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline nbritton

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Re: What to do with a 4,000 V power supply (plus mini tear-down)
« Reply #2 on: November 22, 2015, 06:55:43 am »
 

Offline crispy_tofu

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Re: What to do with a 4,000 V power supply (plus mini tear-down)
« Reply #3 on: November 22, 2015, 09:59:33 am »
Thanks for sharing, really cool!  :-+

If I really put 4kV into that LED it would probably blow like no LED has been seen blowing before.
I would love to see that, entirely new level compared to connecting an LED straight to the mains.  ::)   :popcorn:
 

Offline SeanB

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Re: What to do with a 4,000 V power supply (plus mini tear-down)
« Reply #4 on: November 22, 2015, 11:39:38 am »
Try a glass fluorescent lamp starter. Never was able to find any part aside from the remains of the base with the 2 blackened pins in the bakelite. The dog was skittish the rest of the day as well, after he came back from the bottom of the garden.
 

Offline jeroen79

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Re: What to do with a 4,000 V power supply (plus mini tear-down)
« Reply #5 on: November 22, 2015, 12:31:54 pm »
Topic title is a bit misleading for the members in countries where the , is the decimal separator ;)
 

Offline SharpEars

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Re: What to do with a 4,000 V power supply (plus mini tear-down)
« Reply #6 on: November 22, 2015, 01:54:29 pm »
Topic title is a bit misleading for the members in countries where the , is the decimal separator ;)

Digit grouping comma purged from title...
 

Offline moya034

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #7 on: November 22, 2015, 03:51:47 pm »
What to do with a 4000 power supply?

Easy question! The answer is clear... Plate supply for an RF amplifier in the kW range under development.
 

Offline SharpEars

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #8 on: November 22, 2015, 10:19:25 pm »
What to do with a 4000 power supply?

Easy question! The answer is clear... Plate supply for an RF amplifier in the kW range under development.

I was hoping to find a more practical use case to silence the critics...
 

Offline moya034

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #9 on: November 22, 2015, 10:27:41 pm »
Well if you are ham radio operator like me who likes building stuff I'd say that's practical :)

How about testing CRT's and other HV tubes?

Edit: Also don't forget laser power supply!
 

Offline SharpEars

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #10 on: November 22, 2015, 10:32:11 pm »
Well if you are ham radio operator like me who likes building stuff I'd say that's practical :)

How about testing CRT's and other HV tubes?

Edit: Also don't forget laser power supply!

"Interesting" lasers require far more than 50 mA, though. This supplies maxes out at that current.
 

Offline moya034

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #11 on: November 22, 2015, 10:38:31 pm »
How about a leakage tester? Could also use a voltage cascade circuit to get even higher voltages.
 

Offline SharpEars

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #12 on: November 23, 2015, 12:32:48 am »
The main post has been updated with a real high-voltage demo so as not to disappoint...
« Last Edit: November 23, 2015, 03:12:00 am by SharpEars »
 

Offline Vgkid

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #13 on: November 23, 2015, 03:24:35 am »
I did not see the 200k resistor in the parts list for the thumbwheel assembly, but it might be cheaper to bodge in 2 100k(.50W) resistors in series(as you have done) if you want to stay with the 1W voltage rating. It is cheaper than a single 1W 1% resistors.
If you own any North Hills Electronics gear, message me. L&N Fan
 

Offline SharpEars

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #14 on: November 23, 2015, 02:40:19 pm »
I did not see the 200k resistor in the parts list for the thumbwheel assembly, but it might be cheaper to bodge in 2 100k(.50W) resistors in series(as you have done) if you want to stay with the 1W voltage rating. It is cheaper than a single 1W 1% resistors.

The reason you don't see a 200k resistor in the parts list is because they screwed it up. There are no 200 ohm resistors (those are supposed to be 200k) on the thumbwheel assembly.
 

Offline saturation

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #15 on: November 23, 2015, 04:19:03 pm »
Given so much counterfeit is about, I use mine for kV testing of components. 
« Last Edit: November 23, 2015, 08:14:42 pm by saturation »
Best Wishes,

 Saturation
 

Offline SharpEars

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #16 on: November 23, 2015, 05:30:03 pm »
Given so much counterfeit is about, I use mine to for kV testing of components.

They're all counterfeit until proven otherwise, especially if bought on eBay.
 

Offline Terry Lingle

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #17 on: November 24, 2015, 01:03:08 am »
Looks like that would build a good mouse trap.
 Self cleaning  just an ash grate to deal with . Proper bait placement would make it a low bait use model as wel.l
 

Offline SharpEars

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #18 on: November 24, 2015, 03:35:58 am »
Looks like that would build a good mouse trap.
 Self cleaning  just an ash grate to deal with . Proper bait placement would make it a low bait use model as wel.l

Can I use a 0.1 uF ceramic disc capacitor as fake cheese? Charge it to a nice and cozy 4 kV and when the mouse bites it, well you get the picture...

 

Offline iampoor

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Re: What to do with a 4000 V power supply (plus mini tear-down)
« Reply #19 on: November 24, 2015, 05:27:51 am »
Looks like that would build a good mouse trap.
 Self cleaning  just an ash grate to deal with . Proper bait placement would make it a low bait use model as wel.l

Can I use a 0.1 uF ceramic disc capacitor as fake cheese? Charge it to a nice and cozy 4 kV and when the mouse bites it, well you get the picture...

 :-DD

If you di some wood burning with it, I would be interested in knowing if using a variable supply is worth it or not!
 


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