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Re: 50kV Supply

Posted: Fri Jan 25, 2019 10:20 pm
by Joe Gayo
HV Transformer and Multiplier are included (no driver)

Re: 50kV Supply

Posted: Fri Jan 25, 2019 10:34 pm
by Chris Giles
Thanks very much Joe

Re: 50kV Supply

Posted: Sat Jan 26, 2019 11:39 am
by Rex Allers
The ebay seller is 'bdmerchandise'. I exchanged some emails with him and he seems pretty helpful if not completely aware of details on all these parts.

I got my unit today (the same aluminum box that Joe told us about). As I suspected, and posted earlier in this thread, it looks to be Glassman parts that are based on their ER series supplys. The multiplier module in these boxes is indeed an ER-series part and the transformer looks to be the one used in ER supplies. The ER series is 300 W output.
They had many options, like this:

ER10P30 ER10N30 ER10R30 0-10kV 0-30mA
ER15P20 ER15N20 ER15R20 0-15kV 0-20mA
ER20P15 ER20N15 ER20R15 0-20kV 0-15mA
ER25P12 ER25N12 ER25R12 0-25kV 0-12mA
ER30P10 ER30N10 ER30R10 0-30kV 0-10mA
ER40P7.5 ER40N7.5 ER40R7.5 0-40kV 0-7.5mA
ER50P6 ER50N6 ER50R6 0-50kV 0-6mA
ER60P5 ER60N5 ER60R5 0-60kV 0-5mA
ER75P4 ER75N4 ER75R4 0-75kV 0-4mA

In those, P = positive output, N = negative, and R = both (I think for R, you had to swap the multiplier module to change between P or N.) In the part numbers, the first number (before P/N/R) is kV and after is mA, so the product of those two numbers is 300 (watts).

The units the seller is striping down, I think, are some kind of big complex security xray scanners. I think this HV part powered a small xray tube.

So it looks to me that Glassman sold some custom design components that is very close to the ER supply.

The seller sent me some pictures and it looks to me that he has boards that are ER main boards, except the place that usually has the transformer on the board is unpopulated and the transformer and multiplier have been moved to this separate aluminum box. I think the board and one of these boxes can be paired to make an equivalent to an ER supply. Not simple... you'd need to figure out how to connect AC -- pots for V and I control (or voltages) -- meters or monitors for V and I -- how to connect between the board and this box.

I have purchased one of these ER-looking boards from the seller but don't have it yet. I think he said he had 8 total units that he is stripping down. I think he might be receptive to selling a package with both this box and one of the driver boards.

I can try to share more about how it looks after I get the board. So far, what I'm sharing here just looks good in theory.

Joe made his own driver for the transformer and says he is getting 700 or more watts out (more than twice the 300 W spec). I'm not sure if it is possible to get that power out of the original ER-style board. At minimum, I think that would take some hacking to the current sense which is an input control to the 3525 switcher chip.

Here's a link to one ER manual that has schematics. All the versions are about the same except for the number of stages in the multiplier and the polarity orientation of the diodes.
https://docs.google.com/file/d/0B7IIDFX ... xXTDg/edit

Hopefully I can add more after I get the board. If you contact the seller, tell him Rex

sent you.

-Rex

Re: 50kV Supply

Posted: Sat Jan 26, 2019 8:51 pm
by Chris Giles
Thanks Rex. That is most helpful, particularly the manual. The other manuals I have found have been similar but that one is exactly the right model (board part number matches). Looks like a complete unit could be re-created but would be quite a fiddle.

Re: 50kV Supply

Posted: Wed Jan 30, 2019 6:18 am
by Joe Gayo
Revised my driver. The frequency is lower(30KHz) and the peak switching power is around 1200W. The multiplier and transformer are quite robust in the Glassman stack. The new combination has my device around 1.5M n/sec at near full voltage/current.

Re: 50kV Supply

Posted: Wed Mar 20, 2019 4:06 pm
by Cristiano_Machado
Hello,

Finally I received my unit. Now I am working on the driver.

I would appreciate your comment on my design. This is based in Joe's suggestion (http://www.loneoceans.com/labs/sstc2/), and Gao Guangyan's project.
Driver 2.jpg
Power inverter
The output will be plugged into the unit transformer.
IMG_1944.jpg
Transformer
I am still working on the frequency generator to control the IGBTs.

Thanks for the help.

Regards,

Cristiano

Re: 50kV Supply

Posted: Fri Mar 22, 2019 8:17 pm
by Chris Giles
HI Cristiano

I recommend that you purchase one of the control boards from the seller and use that as a start. Coupled with the HV box it makes a complete Glassman ER PSU minus the front panel components. It has a driver similar to your sketch. You can start from that and then try to hack it to get higher output.

If you choose not to, you can still refer to the schematic for it. Regarding your schematic, you should use a bridge rectifier, and also you would not need a Variac if you use a standard PWM controller/driver IC where you have shown "frequency driver".

Regards
Chris

Re: 50kV Supply

Posted: Sat Mar 23, 2019 10:34 pm
by Cristiano_Machado
Hello Chris,

Thank you for your feedback. I will check this board with the seller.

I completed the schematic, using my initial design. Now I need to figure out the value of interrupter's resistors and capacitor. I think 25 kHz and 40% duty cycle is a good start and it will not stress the unit.

Please fell free to comment and give any suggestion.

Regards,

Cristiano

Controle complete.jpg

Re: 50kV Supply

Posted: Sun Aug 25, 2019 12:00 am
by Cristiano_Machado
Hello,

After some trouble to build my driver, I had a suggestion to use a L298 H bridge to teste my HVPS.

It didn't work very well. I don't know why when it was turned on, the bridge started to make a noise, but it was working. I could check that the transforme has a 1:30 ratio, but when I tested using 1Hz and 12% duty cycle the HBridge exploded.

Any suggestion what has gone wrong?

You can see below how I set up the test, using a L298H bridge, a 24V DC power supply and a PWM generator.
IMG_2157.jpg
and the connection to the transformer:
IMG_2159.jpg
and my PWM generator at 1 Hz and 12% duty cycle.
IMG_2158.jpg

Re: 50kV Supply

Posted: Sun Aug 25, 2019 3:49 am
by John Futter
Cristiano
i'm not surprised your driver blew up
you cannot go to near zero frequency as the impedance of the primary coil will tend to its DC resistance which is very low so you have made a sacrifice to the gods of silicon. The circuit to drive the transformer requires the inductive reactance to limit current to a safe level
notes
25khz is too low 50kHz may be better
I would follow suggestions and buy the driver --it is not a trivial task to design one that does not offer sacrifices to the silicon gods.
Just seeing your half wave DC supply option to power your design shows me that you have little experience in power electronics
Half wave rectification is to be avoided especially when using Variacs so as to minimise DC saturation of the variac core