How would you go about stepping up dc power supply voltage?

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Re: How would you go about stepping up dc power supply volta

Postby Rex Allers » Wed Apr 19, 2017 8:53 am

Ryan,

Thanks for sharing the pdf datasheet. I saved it for future reference. Looks like a nice supply although your 10 kV version is not directly useful for a fusor. Pretty beefy with 1 kw out (100 mA at 10 kV).

I hadn't encountered HiTek before so it was good to learn a bit about these models. I don't think you mentioned, is it a P or N output model that you got? This one looks very much like similar models from Spellman or Glassman. The OL1K series is 1 kw output but you select for purchase a max HV output in the range of 1 kV to 60 kV. The one you got is 103 or 10 kV. I assume that its output is adjustable across 0 to 10 kV. Does the one you got have pots and meters on the front panel or just blank with external control?

Do you have an output cable for the HV? In a quick scan of the manual I didn't see a description of the connection style. Looks like it might be a hollowed out PL-259 like Spellman and Glassman use for 10's of kV. I'd be interested to learn more details about that -- does it have an plug on the inserted end of the cable like Spellman or just a blunt end like Glassman? Anyone know about this?

If you open it up at some point, I'd be interested to see pictures of what's inside. I'm wondering if the multiplier section is potted. The datasheet has this footnote on the 60 kV version...
** 60kV unit has an encapsulated HV assembly

I wonder if that implies the 50 kV and below are not encapsulated? Like maybe possible to see the multiplier components, although probably at least inside some strong insulator box like Glassman does.

I'd like to learn more about these HiTek supplies of this class if anyone has more details.
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Re: How would you go about stepping up dc power supply volta

Postby Rex Allers » Wed Apr 19, 2017 9:35 am

Just thought I would clarify a bit about the PL-259 HV connector I mentioned that some HV supplies use. Here is a picture of a standard panel mount PL-259.
PL-259 panel.jpg
PL-259 panel connector
PL-259 panel.jpg (11.79 KiB) Viewed 127 times

This is usually used for MHz RF connections.

Some of the HV supplies modify this by removing the plastic and center socket so only the hollow threaded metal cylinder is left. This becomes the ground (shield) for the HV cable. A plastic tube is extended inward behind the panel for 6 to 10 inches or so, depending on the voltage it is sourcing. (longer for higher voltages.) At the far end of this insulated tube is the actual HV output connection of the supply.

The high voltage cable is usually a coax, possibly RG-8, with the HV on the center conductor and the shield grounded. The screw-on connector that mates with the PL-259 panel as shown above is clamped to the shield of the cable. The coax is stripped so the appropriate length of just the insulation and center conductor of the cable project into the unit beyond the panel connector (the coax shielding is stripped off on this section) .

The inserted end of this stripped section connects to the high voltage inside and could end in a plug that connects into a socket inside the supply (Spellman does this) or just end in a metal blob that presses against a spring-loaded metal connection inside (Glassman does this).

I hope that word description makes sense. This has been covered in some posts a while back (a year or two?).

So I'm curious if this HiTek OL1K uses a similar HV output connection method, and if it does, what's the end of the goes-in-ta supposed to be?
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Re: How would you go about stepping up dc power supply volta

Postby Ryan Oddie » Thu Apr 20, 2017 8:52 am

[Hi Rex,

I am afraid the power supply wont arrive until at least early next week so some of the questions I wont be able to answer until then.

That said, I asked the vendor to send me a couple of pictures and from them I can tell you a little more about the supply.
1.) I am not convinced it is a 10kV output. Looking at the model number on the back it's OL1000/602/12. According to the spec the 10kV model is the 103 version there is no 602 version(?!). Given the naming structure maybe it is a 6kV version that has been discontinued. I guess I will just have to wait to find out (Part of the fun of buying off eBay I guess - but at least the vendor is offering a full money back guarantee)
2.) I still cannot tell if this is a P or N output model (but the vendor told me he couldn't tell so that's not so much of a surprise). Given I cannot use it for my grid anyway its not too important at the moment (perhaps the '12' part of the model number is actually a badly written 'P'). Anyway, I am assuming the worst case scenario for now.
3.) The output port appears to be similar to a regular beyonet RG-8 connector rather than the PL-259 panel you have described. It doesn't come with a cable so I am hoping it is RG-8 as it should be easier to source. Once the system arrives I will open it up and should be able to tell you (show you) the internal setup.
4.) From the eBay image I can tell that it's only the blank panelled version. Of course, it would be nice if it had the voltage controllers for easy testing but I plan to run it remotely using the 25-pin D connector anyway. Speaking of which have you ever tried to use one of these remote connectors? I am assuming its pretty standard and being a software engineer I am tempted to write an interface for it if one does not already exist.

See image here: http://tinypic.com/view.php?pic=293znfd&s=9
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Re: How would you go about stepping up dc power supply volta

Postby Dennis P Brown » Thu Apr 20, 2017 9:41 am

Any high voltage probe can be used to determine the polarity of a DC voltage supply (as long as its rated max range covers the voltage you are using); most analog probes are, not surprising, designed to only give a reading for positive voltages. If it shows the voltage, the supply is positive. If the voltage reading tries to go reverse (and of course can't - i.e. no reading), then the supply is most likely negative (or just not working.) To determine the polarity and voltage without a HV probe, simply use a voltage divider but remember that this is dangerous and one must follow all high voltage protocols exactly. A digital HV probe should show polarity. Again, don't go above its rating or results will be bad.

I designed my own voltage dividers to work with my digital multi-meter (I use a 1 G-ohm resister wired to a 1 M-ohm resistor creating a divider. This is all mounted in a plastic insulating pipe with low voltage output connectors and a high voltage pin well away from the low voltage connectors.) I use these for both my fusor's neutron detector supply (just a 0.1 - 5 kV supply) and for my 50 kV+ voltage multiplier. Since I use a low voltage digital meter to read the divider's output, both the scaled voltage and its polarity are displayed. This device covers a few hundred volts up to 100 kV all with extreme accuracy!

No one ever doing fusor work should be without a high voltage divider that can safely be used with their standard multi-meter; yes, I have a analog probe that reads up to 45 kV but the dividers can be hard wired into a given setup and are useful to cover all sorts of ranges that one may or may not realize they need until later (that is, after getting a HV probe that can't read the given range they now want to cover ...either because it is too low for a high end probe or high for the probe. Try reading 1.95 kV on a 45 kV analog HV probe!)

AS for a D-type control port, I hooked up a 35 kV supply I had to both read its voltage and control said voltage output. The pin connection was specified by the manufacture and worked great just using analog control inputs/reading. It would not work with a computer interface without a A/D interface card since the voltage ranage was well outside std computer voltages. That was something that I had no interest in making since the analog controls were simple to handle.

The HV output connector is standard for systems up to 10 kV and you should have no issue getting a cable BUT be warned, standard coaxial cables might fit but are totally incapable of carrying such dangerous voltage levels. Do get a cable that is rated for the given voltage.

Also, never fail to properly ground the PS before use.

Check to see if any jumpers are required to get the system's HV to work. My - 40 kV Glassman must have such a connection or else its HV will never come on.
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Re: How would you go about stepping up dc power supply volta

Postby Richard Hull » Thu Apr 20, 2017 2:34 pm

Your output connector is a standard SHV BNC type connector. It is tough to think that can handle the max voltage! The issue will be the cable's insulation. You will, indeed, need a well done cable and connector.

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Re: How would you go about stepping up dc power supply volta

Postby Rex Allers » Fri Apr 21, 2017 2:18 am

Thanks for the best answers you can give to my questions. From the picture, I agree with Richard, that's the high voltage SHV variant of BNC connector for output. Normally these are rated to 5 kV but a note I saved from somewhere says they can be had rated for higher voltages. In any case, that kind of connector seems to make the interpretation of the model number at a 6 kV supply probably right. If you want to use the supply, you should probably shop for a mating connector to plug into it.

The back-panel picture looks a bit different from what's in the datasheet you linked. There's 2 fans in the datasheet but only one in the picture. Biggest difference is the picture seems to have two 25-pin connectors with only one described in the datasheet. The datasheet describes the pins as mostly analog signals for control and monitoring. I can't think why there would be two if they are like what is described, as they would fight each other. [It doesn't really matter, but one of the connectors in the picture looks to have a sex changer plugged into it.]

I agree with Richard that the pins of the 25-pin connector as described in the datasheet are more of an analog thing and not something you would directly control with software. Mostly they look similar to other similar supplies with 0-10 V in to set voltage and current limit points and 0-10 V out to monitor V and I that is being generated. I don't quite understand what the voltage program Hi and Lo pins mean. I think they are saying Lo is just the reference for Hi (normally that would be ground) but if so why isn't there Hi and Lo on the current program. Maybe someone else knows exactly what they mean.

I would guess this supply is some kind of custom version. Maybe the vendor will share more details with you. If you don't get more guidance, I would think figuring out why there are two 25-pin connectors and if they match the datasheet might be a bit of a project. You'll need to build some kind of circuit to control and monitor the connector before you can test the supply.

Keep us posted on any developments.
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Re: How would you go about stepping up dc power supply volta

Postby Ryan Oddie » Sat Apr 22, 2017 12:51 pm

Hi All,

For anyone interested in the internals of the HiTek OL1000 Power supply I opened it up this morning and took a couple of pictures. I don't really have much of a clue what each part is / does (if anyone can break it down or point out the key components that would certainly be interesting from my point of view). I have been in contact with the manufacturers in order to get hold of the full instruction manual and will post it online if / when they arrive.

Image

Image

Image

Image
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Re: How would you go about stepping up dc power supply volta

Postby Rich Feldman » Sat Apr 22, 2017 2:59 pm

Nice pictures, Ryan. But they're so big that embedding them makes it inconvenient for many readers to see them whole. Learn to use the Upload Attachment button. It puts the image in a separate archive. In its place we see a clickable thumbnail, like this:
snip2.PNG

In lower right corner* of first image, the fluted white tubular thing is a bobbin for HV secondary winding of a high frequency transformer. Wires from there go left, to a board (or a potted unit) which will have rectifiers and maybe a voltage multiplier, and HV divider for feedback. That feeds the left end of the deep HV output connector.

*as presented. Windows is weird about picture orientation bits.
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