DIY X-RAY generator made of eBay parts

[PhotonLab]

Hello, this is my first post, I would like to share my experience on building a X-RAY machine based on parts bought on eBay.



The assembly I bought is an almost complete X-RAY head:

1) X-RAY tube D-045
2) Cockcroft–Walton 6 stages multiplier
3  High frequency tranformer board (no driver)

I did rewind the original transformer, becouse the primary was made to work in SMPS mode (powered my mains), to work with a ZVS driver.

The tube filament current is provided by a toroid transformer that is feeded by a very simply single transistor self-oscillating  driver. The toroid primary consists of 15 + 15 turns center tapped while the scondary is 3 turns of high voltage cable. This ensure insulation of the HV source.

An exposure timer has been added to the circuitry.

You can see the results in the attached pictures.


Any comments or questions are welcome.

Mario

[Luca c.]

Hi Mario, very neat build, can you share the schematic for the filament supply circuit? also i was curious if you are able to modulate the current in the filament to control the x-ray hardness? In the past, I also tried to use galvanically insulated filament transformer to feed the glowing filament in the tube, with a small Chinese zvs module, but I found it very hard to control the filament current (and consequentially the HV current flowing in the tube) by varying the input voltage to the oscillating circuit.
Also more or less what is the power consumption of the HV system?

[PhotonLab]

Hi Mario, very neat build, can you share the schematic for the filament supply circuit? also i was curious if you are able to modulate the current in the filament to control the x-ray hardness? In the past, I also tried to use galvanically insulated filament transformer to feed the glowing filament in the tube, with a small Chinese zvs module, but I found it very hard to control the filament current (and consequentially the HV current flowing in the tube) by varying the input voltage to the oscillating circuit.
Also more or less what is the power consumption of the HV system?

Hi Luca,
here's, in MarioCAD format , the schematic of my very simple driver.


 
You can control the heater voltage varying the input voltage of the driver from about 12 to 18 Vdc. In my setup I got 3 Vac with 18 Vdc input at the driver. However I run my tube at about 2.5 Vac.
The whole system at maximum power runs on about 250 W.
Ciao
M.

[klugesmith]

Nice work, Mario.  Welcome to the forum!

Here is a HV-isolated filament supply with no transformers or batteries, reported in 2010.
It's a motor-generator set with insulating drive shaft, made from a blender and a cordless drill.


First glimpse of calibration chart:
Verb Filament_voltage
----- -----
Stir 1.9
Whip 2.3
Blend 2.9

[PhotonLab]

Nice work, Mario.  Welcome to the forum!

Here is a HV-isolated filament supply with no transformers or batteries, reported in 2010.
It's a motor-generator set with insulating drive shaft, made from a blender and a cordless drill.


First glimpse of calibration chart:
Verb Filament_voltage
----- -----
Stir 1.9
Whip 2.3
Blend 2.9

Lovely solution, what about a hamster powered wheel connected to an alternator?
https://hackaday.com/2010/10/20/rodent-based-power-generation/

[alan sailer]

I like the filament supply idea. Can you share a simple block diagram of the parts?

It looks like your are using an Ebay ZVS driver to drive some sort of HV AC transformer, then into
a 12 stage voltage multiplier.

Cheers.

[PhotonLab]

I like the filament supply idea. Can you share a simple block diagram of the parts?

It looks like your are using an Ebay ZVS driver to drive some sort of HV AC transformer, then into
a 12 stage voltage multiplier.

Cheers.

Hello,
your guess is correct: its a cheap ZVS (Amazon) who feed an hand made winded ETD49 ferrite core  transformer (about 6T primary, 500T secondary), the Cockcroft–Walton multiplier is a 6 stages bipolar (each stages is made by 2 diodes + 2 capacitors) , theres an exposure control based on a 555 time and a remote control that turn on the HV voltage and also trigger at the same time the Olympus camera. All analog old style stuff.
Soon I will publish update pictures of the setup and a block diagram
Cheers
M.

[arturk]

Hi Mario, great project!

Coincidentally I have purchased the same gear of eBay while ago and I am working on similar machine.
I struggled little bit with the original transformer and also came to conclusion that it would have to be rewinded in order to work with TVS driver.
While searching for some ideas how to power filament through the toroid transformer I came across of your post.
I really like your driver and will build one in the next few days.

I have a few questions.

• With your rewinded transformer at about 6T primary and 500T secondary, what voltage do you supply TVS driver with?
  Did you not run into any problems by not submerging high voltage circuits in the oil? I got transformer working (with original windings) and it started arc'ing internally at just few thousands volts during my open air test. I wonder if there is something wrong with it.
• How long are are your cycles?
  
• What is the white piece of square material attached to the housing of the tube? Seems like there is also piece of it between transformer and multiplier board.

Again, thanks for sharing your project with the community.

 

[PhotonLab]

Hi, thanks for you interest, the project has been update especially on the safety part.
So here's a quick answer to your questions:

-With your rewinded transformer at about 6T primary and 500T secondary, what voltage do you supply TVS driver with?
    from about 16 to 22 Volt

Did you not run into any problems by not submerging high voltage circuits in the oil? I got transformer working (with original windings) and it started arc'ing internally at just few thousands volts during my open air test. I wonder if there is something wrong with it.

This happen if the output of the hgh voltage multiplier is unloaded, if you connect the tube with the heather energized this is not goooing to happen. I did some test with a load resistor with an impedance similar to the X-RAY tube, about 60 MOhm.

How long are are your cycles?
Resonance is at about 35 kHz

What is the white piece of square material attached to the housing of the tube? Seems like there is also piece of it between transformer and multiplier board.
Screens

Hope this help, stay safe and always have a dosimeter at hand.
Ciao.
Mario

[PhotonLab]

[zgoode]

Hi Mario,
First I want to say awesome work you did here with this!  Second, I think you are the guy that replied to my reddit post a few months back.  if so Hello again!
I had a few questions about how you did you circuit here and was hoping you might be able to clarify some things for me.  I'm trying to get my tube up and running, but shelved this a few months back and am finally looking at getting back to it.
You mention that you were planning on posting a block diagram at some point and I would love to see that to get a better understanding of the system as a whole, assuming you got around to making it.  The pictures of your setup are definitely very useful here as a starting point for me.
If I understand your post right, the only part of the original circuit (not including the external extra driver boards you had to add) that you modified was the primary winding of the transformer?  I see you mention something about how it was made for SMPS mains and you are driving it via ZVS now on a lower DC voltage.  Did you just change the winding ratio to accommodate whatever voltage you were using, or did you change something else in the fundamental construction?

[inanium]

I'm also curious about the transformer modifications as I just picked up a similar unit off ebay.

I'm guessing you just modified the primary such that you could drive it with a relatively low voltage ZVS driver powered by 12-24v vs a SMPS which is switching, I don't know, line voltage(120vrms)?

Did you consider putting the tube and HV section into mineral oil?  I'd be concerned that arcing or corona discharge might occur without an oil bath.  The mineral oil also might help to keep the tube cool.

Thanks!