Hipotronics 30C Wiring and Connectors

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Maxwell_Epstein
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Hipotronics 30C Wiring and Connectors

Post by Maxwell_Epstein »

Hello All!

I have recently acquired an old 1994 Hipotronics 30C unit from eBay. I plan to use it with a variac to power my fusor up to 30kV at 10mA. When I unpacked the unit and started planning its use with my system, I noticed a problem. The high voltage connectors for the +30kV and -30kV terminals are over 6 inches deep. I was able to find a picture of this sort of cable online, but do not know how I could go about finding one for myself.

Do any of you know what sort of connector and wire I could buy or build for this setup? Additionally, how might this wire connect to my feedthrough on my fusor in a way that avoids corona discharge? For my 12kV NST supply, I have been using standard ring terminals, but this seems insufficient for 30kV. Finally, do you think I need to ground the unused +30kV terminal on the transformer to prevent it arcing internally or is this not necessary?

Thank you!
Max E.
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Richard Hester
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Re: Hipotronics 30C Wiring and Connectors

Post by Richard Hester »

It may hook up via some RG8U coax with a banana plug soldered to the center conductor. The clamps you see would go around the braid for the return connection. I have a couple of the larger Hipotronics HV tanks at home that have similar connections.
Richard Hester
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Re: Hipotronics 30C Wiring and Connectors

Post by Richard Hester »

I misspoke a bit - the center connector is obviously for the input voltage, and the two capped receptacle on either side are for the HV and return. I think the thing will still take stripped RG8U coax with a banana plug soldered on the end to make contact. In addition, you will need to get a couple of PL-259 style connectors and drill them out so you can screw them on to what are most likely threaded collars in order to hold the coax in place.
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Liam David
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Re: Hipotronics 30C Wiring and Connectors

Post by Liam David »

What Richard said--a long stripped section of RG8U coax.

Whether you can connect the +30kV to ground depends on the internal isolation of the unit. If the -30kV side and the transformer's internal insulation can tolerate -60kV relative to ground, and assuming it is not center-tapped, then it would be ok. That would give you a -60kV supply. Otherwise, I would leave the +30kV side floating, giving you a -30kV supply. It's hard to say without a manual. Excepting more information, I'd stick with floating the +30kV side for now. Do NOT ground the +30kV side without knowing more. Perhaps in the future when you're fusing and 30kV is too low you could attempt the 60kV change, if the transformer indeed has no center tap.

Ring terminals are ok, even for 30kV, as long as you keep things relatively smooth. Above that, ring terminals are still ok but you should shield them with spheres or toroids.
JoeBallantyne
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Re: Hipotronics 30C Wiring and Connectors

Post by JoeBallantyne »

I have used a Hipotronics power block that had a couple of RG8U HV lines coming out of it, and was rated for 22kV at 5.5mA IIRC.

Similar power blocks are also used as the core of fancier Hipotronics HV power supplies - with variable voltage control, current limiting, auto shutoff on excess current, etc.

For the power block I worked with, if you wanted positive voltage, you grounded the negative ouput line to the grounded case. The max voltage out was the rated voltage of 22kV on the positive output cable so +22kV.

If you wanted negative voltage out, you grounded the positive output line to the grounded case, and again the max voltage out was the rated voltage of 22kV on the negative output cable so -22kV.

I suspect that this Hipotronics transformer/supply is equivalent. You ground the case to earth ground using the bolt and nut labeled GND next to the negative output terminal, and you can either get +30kV out of it, if you ground the negative output cable to the case and connect the positive output cable to your load, or you can get out -30kV if you ground the positive output cable to the case and connect the negative output cable to your load.

I don't think you will be able to get 60kV out of it.

However, that is easy to determine if you have a variac, and an HV meter. Set the input voltage to some known low level - like 12V rms, and see if the voltage between the positive and negative terminals is 3kV or 6kV. If it is 3kV, then you won't get 60kV out of the supply - only 30kV, and it will likely work as I outlined above - you can get either polarity by grounding the opposite polarity output to the grounded case.

If you get out 6kV with 12V RMS in, then that is a very different beast from what I have experience with, and you may not be able to ground either of the outputs.

Please be exceedingly careful. That supply can kill you. When you build your cables, I would strongly recommend that you ground both ends that you will be connecting to your loads BEFORE you insert the other end into the supply. Make sure there is NO POWER connected to the supply when you first insert the cables. There may still be charge sitting inside that thing. You do not want to get zapped when you first insert your newly built output cables.

The other thing you can probably do to dissipate any charge inside the supply is to connect the VM terminal to GND and to the case ground. That will likely safely discharge any residual charge in the supply. But I would still ground cables you build the first time you insert them to the supply. Make sure once you have the cables safely inserted, that you disconnect VM from GND before you connect power to the input and try to use it. Also, I would only ever use this supply with a variac - so connect the variable output of the variac to the input of this supply. Otherwise if you just connect 120V straight to the supply it is going to immediately output 30kV. Which generally with a fusor is NOT what you want. You want to be able to control the HV output, and bring it up slowly. Much safer that way.

Because this supply can be wired for either 220 or 115, you can also take the output of your variac - assuming it goes from 0 - 120V or 0 - 140V, and wire it up to this supply as if it were 220 instead. Connect it up as shown in the 220 diagram. Then the max the supply will output is 15kV. Perhaps at first you might want to use it that way, as 15kV should get you a plasma, and you can learn how things work, and then later you can wire it up in the 115 configuration and get the full 30kV output.

This supply should allow you to do fusion. You should definitely also put a fuse block in the input line, so that in case of a short you don't fry the supply.

Joe.
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