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Reverse-engineering a small XRT

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Andre

Tue Oct 16 2012, 12:04AM

Registered Member #6921 Joined: Wed Sept 26 2012, 07:47PM
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Posts: 109

I will like to see more pictures on the secondary of this transfomer, this is porn for engineers :)

how did you found the saturation point of this transfomer?

Tony Matt

Tue Oct 23 2012, 04:52PM

Registered Member #3700 Joined: Sat Feb 19 2011, 12:59PM
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Posts: 107

Hi Xray !
I also like the "inverse voltage protection circuit" , or any device to treak the remanent magnetic flux.
Can you post the Gendex GX-770 circuit schematic ??
thanks
Tony

Xray

Tue Oct 23 2012, 08:27PM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

Tony Matt wrote ...

Hi Xray !
I also like the "inverse voltage protection circuit" , or any device to treak the remanent magnetic flux.
Can you post the Gendex GX-770 circuit schematic ??
thanks
Tony

If you are looking for the schematic diagram of the entire machine including the control circuits, I do not have that in digital form. You may be able to get a copy from Gendex for the asking if you tell them you are a dental equipment repair technician. The schematic diagram of the tubehead is very simple. Basically it's a transformer with 110VAC primary winding, and two 35KV secondary windings. There is also a low-voltage winding for the filament. The filament winding floats at 35KV above ground, and is wound on the same hv secondary that connects to the cathode of the X-ray tube. There is also a resistor that connects between the filament winding and the cathode hv winding. That resistor provides a bias for the grid of the tube.

Hope this helps.

Tony Matt

Wed Oct 24 2012, 03:10AM

Registered Member #3700 Joined: Sat Feb 19 2011, 12:59PM
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Posts: 107

Xray;

Thanks.

Tony

Tony Matt

Wed Oct 24 2012, 03:24AM

Registered Member #3700 Joined: Sat Feb 19 2011, 12:59PM
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Posts: 107

Hi Klugesmith.

I have understand that there is a airgap between two E cores.
Is the airgap an insulating material as cardboard, fiber presboard ? let me know the thickness.
Is the airgap in the central leg of the E core ? or it is distributed in the 3 legs of thre core?

Let me know how you did to minimizing the airgap.

thanks

Andre

Wed Oct 24 2012, 04:26AM

Registered Member #6921 Joined: Wed Sept 26 2012, 07:47PM
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Posts: 109

So is the x-ray tube being power by AC voltage, no rectifier diodes?

Xray

Wed Oct 24 2012, 04:46PM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

Andre wrote ...

So is the x-ray tube being power by AC voltage, no rectifier diodes?

Yes, the tube operates in "self-rectification" mode. The anode and cathode are connected directly across the hv windings of the transformer, and it conducts every half-cycle of the sinewave when the anode is positive. In countries that have 60Hz mains like the U.S., the tube produces 60 pulses of X-rays during each second of exposure time. In the U.K. it produces 50 pulses per second.

Xray

Wed Oct 24 2012, 04:54PM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

Tony Matt wrote ...

Hi Klugesmith.

I have understand that there is a airgap between two E cores.
Is the airgap an insulating material as cardboard, fiber presboard ? let me know the thickness.
Is the airgap in the central leg of the E core ? or it is distributed in the 3 legs of thre core?

Let me know how you did to minimizing the airgap.

thanks

Tony - There is no air gap between the two sets of E cores. The ends are butted together and tightly clamped with the brackets and bolts. There is spacing between the primary and secondary windings, which is there to prevent arcing between the windings since the primary winding is essentially at ground potential, and the secondaries are sitting at 35KV each above ground. The insulation material is mostly some form of "fish paper", in combination with the oil that fills the entire tube head housing.

Andre

Fri Oct 26 2012, 08:24PM

Registered Member #6921 Joined: Wed Sept 26 2012, 07:47PM
Location:
Posts: 109

Xray wrote ...

Tony - There is no air gap between the two sets of E cores. The ends are butted together and tightly clamped with the brackets and bolts. There is spacing between the primary and secondary windings, which is there to prevent arcing between the windings since the primary winding is essentially at ground potential, and the secondaries are sitting at 35KV each above ground. The insulation material is mostly some form of "fish paper", in combination with the oil that fills the entire tube head housing.

xray, so the secondary has some kind of fish paper between each layer? do you know how many layer it has?

Xray

Fri Oct 26 2012, 09:48PM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

Andre wrote ...

xray, so the secondary has some kind of fish paper between each layer? do you know how many layer it has?

Nope... never bothered to count them. Why is that important to you?

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