50kv Spellman PTV Power Supply Setup

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Jackson Oswalt
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Joined: Thu Jul 13, 2017 1:10 pm
Real name: Jackson Oswalt

50kv Spellman PTV Power Supply Setup

Post by Jackson Oswalt » Thu Nov 16, 2017 3:11 am

Hello all once again!

First I would like to say I'm not an electrical engineer nor the most skilled amateur, but I do understand electronics and wiring enough to understand the majority of the diagrams in the manual discussed below. It's the more intricate details that I need assistance with.

As some of you might remember, there was a post a while back titled "Christmas Comes Early". It was about these 50kv @ 4ma Spellman power supplies being sold for $150 on eBay. Supposedly they could be modified to output 50kv @ 7ma, equaling 350 watts (although I'm far from testing that process out). Anyways, I've been waiting for them to restock and finally they did last Wednesday. After receiving confirmation that they are are indeed new and are of negative polarity, I ordered one and received it that Friday. Of course, cheap supplies like these come with a major downside: they don't come with any built in controls what so ever. So, I immediately got to work wiring the voltage and amperage control with the information provided in the manual. Link to the manual: https://www.spellmanhv.com/-/media/en/T ... PTVMAN.pdf. Unless you've got previous experience with these supplies, which I'm sure quite a few of you do, I suggest reading the manual before the rest of the post.

Today I finally managed to get the supply to output some voltage, but since I don't own a high voltage probe nor the proper HV lead (I have a question on the 50kv output lead below), I'm left to believe what the voltage monitor plugged into a multimeter tells me, which is clearly unreliable. The reason I say that is because, when the supply is switched on with the enable/disable function (figure 3.4 in the manual), the input reads twice as much as when the supply is switched off. On top of this, for some strange reason I can't input the full range of 0-10vdc, which is supposed to determine the output. At around 4 volts the power supply switches on, and at 5.8 volts it shuts off. By the way, I consider "shutting off" to be when the buzzing noise turns off (not corona, but the normal magnetic fields bouncing off the walls of the supply noise). When I'm not between the values of 4-5.8 volts, the multimeter reads zero, despite there obviously being an Input. The setup I use to supply 0-10vdc is a 12vdc rechargeable lithium battery that feeds into a 0-12vdc dimmer designed to control LED's. Sounds crude, and it is, but it does its job and it's all I had around. From the outputs of the dimmer the volts head to their respective pins on the power supply. You can see what connects to what in the manual linked above on pages 4 and 7. One point of failure that may be the result of the strange anomalies listed above could be crude system. This is where my lack of electrical know how will certainly show. The manual calls for a signal, and I'm almost positive what I'm imputing is far from a signal. I've already ordered a 0-10 vdc signal generator, but the main reason is so I can eliminate any possible flaws in my input setup. On the other hand, I could be completely wrong. That's why I decided to bring this to the far more experienced people on this forum.

Below are links to the two items that make up my 0-10vdc input setup along with a video that will hopefully explain the situation to those who can't make out anything I just said. I have a feeling that'll be a lot of people.

12vdc 2800mAh Lithium Battery: https://www.ebay.com/itm/DC-12V-2800mAh ... SwmtJXb8EB

0-12vdc, 8A dimmer: https://www.ebay.com/itm/Brightness-Swi ... SwSzdXDKDB

Video: https://drive.google.com/open?id=1A7gfU ... 88c9G20wG2. It's not very good quality, but you get the idea. However, as you can see the multimeter reads out around 10vdc. This is what happens when I attack the multimeter test leads directly to the output of the dimmer. Despite the different reading, the result is still the same: only a very little area of 0-10vdc range is allowed, and as soon as I exceed that range the voltage drops. I'd be more than happy to make a video about any other aspect described above.

If anyone has info on where I could purchase or how to fabricate a prope HV output lead for this model it would be much appeeciated. As always, I'm more than happy to answer any questions. Thanks!

- JO

Silviu Tamasdan
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Real name: Silviu Tamasdan
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Re: 50kv Spellman PTV Power Supply Setup

Post by Silviu Tamasdan » Thu Nov 16, 2017 3:52 am

I'm pretty sure these "LED dimmers" don't output a continuous voltage but a train of pulses. Being that most if not all of them are PWM based. The supply doesn't expect to be controlled by a train of pulses but by a continuous voltage. A much easier and cheaper way to generate such a continuously variable voltage would be a potentiometer of sufficiently high value (10-100kohms should do) connected across your 12V battery (or even a 9V battery for testing purposes) and its sliding contact connected to the PS control pin.
There _is_ madness to my method.

John Myers
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Re: 50kv Spellman PTV Power Supply Setup

Post by John Myers » Thu Nov 16, 2017 5:13 am

Wow, your making things more complicated then they need to be.
Just follow figure 3.2B which only needs two 20K potentiometer and two 100 ohm resisters. You don't even need an external supply (pin1).
Like Silviu said, LED dimmers use PWM control or control the current output neither of which you want.
In your video you can tell the dimmer is doing something weird since the voltage rises to past 10V then fall back down even though it looks like your still increasing the knob.

Silviu Tamasdan
Posts: 147
Joined: Wed Jun 28, 2006 11:17 pm
Real name: Silviu Tamasdan
Location: Connecticut

Re: 50kv Spellman PTV Power Supply Setup

Post by Silviu Tamasdan » Thu Nov 16, 2017 12:41 pm

Huh I hadn't even realized the PS conveniently exposed a 10V reference on the control connector. Then it's as easy as 2 pots, one for voltage and one for current...

Anyway thanks for the heads-up on this source's availability. I bought one to play with. :)
There _is_ madness to my method.

Jackson Oswalt
Posts: 96
Joined: Thu Jul 13, 2017 1:10 pm
Real name: Jackson Oswalt

Re: 50kv Spellman PTV Power Supply Setup

Post by Jackson Oswalt » Sat Nov 25, 2017 2:04 pm

Thanks for the help.

After a little bit of work I managed to wire the potentiometers properly and it now works flawlessly. I'm now in the process of modifying it for 7ma output, so if anyone knows something I should be aware of before doing so, please point it out to me.

Thanks!

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