My new x-ray transformer

[AlexanderHun]

Hello!

Introducing my new toy, I recently managed to buy a high-voltage transformer for an industrial X-ray machine and the associated control panel.
The high voltage transformer can supply voltages between 70-200kV, up to 10mA.
It's still on the way for now, I ordered it, but I'll add more detailed photos, and I also have an X-ray tube that I can operate in this way.

[AlexanderHun]

Hello!

This week the courier will bring the things shown in the picture, my question would be the silicone oil recommended for the high voltage transformer, what are your thoughts on it? Or should I stay with the transformer oil? I know I'll have to vacuum the transformer

[Mads Barnkob]

Nice control panel, it looks exactly like the system I got recently. There is some years between the systems and yours is older, but generally it is the same knobs/meters to control it:

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Did you get more parts with the transformer? It looks like high voltage diodes and voltage multipliers are missing? Or are those pancake coils really specified up to 200 kV?

The 4 wires coming from the transformers must be each their set of primary windings for the inverter. That dual midpoint grounded high voltage transformer i common in the x-ray generators, like the large siemens x-ray head I took apart here. I still have the transformers and output voltage multiplier if you are interested in buying that. I think it was something like 1000 Hz pulsed, I seem to recall that I talk about that in the control panel video of that system.

[AlexanderHun]

Hello!  This is a 50Hz X-ray, the tube went with alternating current, in half wave.  That’s the high voltage transformer, their primary coils are connected in parallel, controlled by a variac  that is in the control unit.  There are no multipliers, the transformer is almost 20kg, it could deliver 200kV.



Before the owner disassembled

[AlexanderHun]

Hi!
The package has arrived, I think I managed to order something huge again. I attach pictures, there is even an X-ray image intensifier included in the package if you are interested in someone doing pictures! This transformer is so big that I'm afraid to install it ....

[MRMILSTAR]

"Big" is a relative term. Compared to my 10 KVA 300-pound pole transformer, your X-Ray transformer doesn't look that big. 

[John123]

Does that need to go into oil?

[AlexanderHun]

Hi, yes, in oil, or in silicone oil.  The latter was suggested to be better than transformer oil, I have no experience with it.

[AlexanderHun]

Test, so far without HV transformer, took two days before I found all pins (pinout).

[klugesmith]

WHat a nice acquisition!

Regarding oil immersion of x-ray transformers, especially those working at 50 Hz or 60 Hz (so secondary winding have many many turns of very fine wire).

My unpracticed understanding is that not only does oil potting depend on using a vacuum,
you are supposed to apply the vacuum before the oil.  The tanks are strong enough to withstand full vacuum.
It's in the rules when you read about installing or servicing pad-mounted utility transformers.

Suppose you dunk a transformer into a tank mostly full of oil, and the secondary coils carry a few tiny air bubbles in with them.
If you then pull a vacuum, even perfect vacuum above the oil, the absolute pressure at the air bubbles can't get lower than about 10 torr.  An exception is permitted if you turn off Earth gravity during the procedure.

Air bubbles will temporarily expand by a factor of 4 or 5, but that doesn't guarantee that they will escape and float to the surface.
On another forum there have been plenty of reports of re-potted XRT's being destroyed by internal arcing, under the oil.  I saw one posted a few weeks ago.

Maybe most people are more lucky.  Reminds me of teenagers handling latex balloons filled with oxygen and acetylene, to make controlled  bangs, in the pre-internet era.  If spontaneous explosions happened 10% of the time, the lucky 90% would tell their friends, who would copy the unwise procedure until somebody got hurt.

[MRMILSTAR]

... Reminds me of teenagers handling latex balloons filled with oxygen and acetylene, to make controlled  bangs, in the pre-internet era.  If spontaneous explosions happened 10% of the time, the lucky 90% would tell their friends, who would copy the unwise procedure until somebody got hurt.

When I was a teenager we used to experiment with calcium carbide nuggets. One time I placed some in a bowl of water and then placed that inside of an empty extra-large-size Tide soap box which had a volume of about one cubic foot. I waited a few minutes for the acetylene to fill the box. I then brought a lighter near the open end of the box. That is the last thing that I remembered for several minutes. The explosion threw me back about 10 feet and stunned me for several minutes. My ears were ringing for about 30 minutes. Luckily I survived. 

[AlexanderHun]

Hi, it will be filled with silicone oil, its properties are very good, it is water repellent, according to its data sheet its penetration is 14kV / mm, of course I vacuum it.

[DashApple]

Do you have a supplier for the silicone oil ? , Currently I use transformer grade mineral oil with my X ray transformers , but think changing over may be a better solution for longer life ?


When I vacuumed my small transformer , It took around 7 days straight and I used a small vibration module to help move the trapped air , Worked really well .

After the 7 days , No more air bubbles could be seen and i stopped the vacuum , Seems to work fine currently : )

[AlexanderHun]

Hi, you can buy it in a webshop in Hungary.  It costs quite a lot, but it's worth it.

[AlexanderHun]

I couldn't stand it, I tested the transformer a bit, I don't go up without oil, I ordered it already but it hasn't arrived yet. 

https://www.youtube.com/watch?v=YpRWmy82Zcg

[Mads Barnkob]

Test, so far without HV transformer, took two days before I found all pins (pinout).

Could you please share the pictures of the plugs and their pinout? If I am lucky, then there is some kind of standard that will fit my unit

[AlexanderHun]

Thanks for the help, these connectors are old Russian standards, I managed to find all pins.  I am currently focusing on the HV transformer.

[pawcio681]

Hi,
I am very glad that I found your post. I also have a device from this manufacturer, only a different model. Unfortunately, I do not have the cables to connect the control unit to the x-ray head. Do you know how to determine which pins should be connected with each other so that the x-ray head will vein without opening it? Or do you have the pin assignments identified with you?

I attach photos of how the pins in my machine look like, as you can see, they differ in the number of pins for this I have a problem with their connection.

I will be very grateful for your help

[AlexanderHun]

Hello!

Thanks for writing, although I didn't have a controller like that. Some version, the type of connector for me, isn't like that, but it's not hard to decipher where it's going. However, this is a 200kV industrial X-ray, just be careful with it.

[pawcio681]

Thank you for answering,
I do x-rays professionally, that's not a problem.  Do you know how to identify what to connect to make the device come to life without opening the head?

[AlexanderHun]

I have a circuit diagram somewhere not exactly for this but it can help you a lot, I'll find you tomorrow.