Questions about HV rectifier

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Tony Lai
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Re: Questions about HV rectifier

Post by Tony Lai »

Thanks for your advice.
I'm reluctant to be electrocuted so I will be wearing proper 35kv rated working glove, also I'll be using 40kv rated wires for wiring. For the grounding, put aside the roughing pump that I even planned to just rip the grounding wire from the three prone cables, I'm quite sure that 'ground' pin in the schematic of my Edwards ext70 turbo is not connected to the power supply. Oddly the ground pin of the turbo is just neglected and left by its own on the schematic, its power supply is grounded. Can I refer this to a safety feature? To stop the ground loop from damaging the equipment?
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Rich Feldman
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Re: Questions about HV rectifier

Post by Rich Feldman »

To "Stop the ground loop from damaging equipment" sounds like a worry from someone who would be hard pressed to explain the problem.
You referred to a video that mentioned destruction of a turbo pump, but was that because of a ground loop?

I think there are two factors that matter in groundING topologies. (excluding neutral side of AC power, aka groundED conductors).

There's a safety thing: Protect against electric shock. Electricity on conductive equipment cases, introduced by a fault, is diverted to the grounding network. Normally the supply circuit breaker then trips, unless fault current is much too low to produce hazardous voltage on grounding network. Consider interruptions due to plugs being unplugged, wire connections coming loose, etc. You need to learn more before you can properly justify disconnecting the 3rd prong of any AC power plug connection, even if the associated equipment is bolted to other grounded apparatus. How 'bout test runs of, say, a backing pump when it is temporarily unbolted from the metal cart?

The other is small voltage drops from point to point, due to currents in the grounding network, or induced by EM fields.
In some cases they could be a nuisance for instrumentation, but I think unlikely to hurt anyone or damage equipment. Tesla coils might be an exception.
All models are wrong; some models are useful. -- George Box
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Dennis P Brown
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Re: Questions about HV rectifier

Post by Dennis P Brown »

Let me clarifry a bit - ground loops affect micro-electrontics - not transformers, mechanical vacuum pumps or any moderate current system. This isn't an issue for a turbo controller or pump - the only device that might be an issue would be a sensitive amp for a detector.

The issue is - are your plugs connected to a proper ground? A simple plug in device will confirm whether your ground is valid and also the polarity. They sell these - this is just one example of many and they are rather cheap:

https://www.staples.com/Ideal-GFI-Recep ... 5oQAvD_BwE

More to the point, a direct plasma short to a turbo could harm the controller but via a common ground (if it is valid), never. Apparently I wasn't clear - waxing on the subject too much on my part.

I cannot say this enough - the use of safety gloves isn't a good idea nor something you should depend upon (a microcrack in it would allow a lethal shock.) The only safe method is to never work on a hot (i.e. energized) high voltage system. If you need gloves to operate your fusor then something is very wrong.

Chris and Rich are offering a lot of good advice.
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Bob Reite
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Re: Questions about HV rectifier

Post by Bob Reite »

Never defeat the safety ground! Make it part of your grounding system.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
Tony Lai
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Re: Questions about HV rectifier

Post by Tony Lai »

Thank you Rich, Dennis and Bob for reiterating the safety issue. I would definitely prioritise the safety over anything.
I know that it is simply daft to neglect the grounding of any electronics. I have never thought about the issue of killing electronics through the grounding circuit, just terrified by the fact that there is an example. I'm really not sure about the exact reason of how that member has killed his turbo as he did not shot the video specifically for this issue. I own one of those ground testers and is sure that my grounding circuit is good ----- that is being fully checked and optimised back in the days when I dived deep into those hifi speakers&amplifiers, probably I will just put this issue aside and focus more on my own safety......
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Richard Hull
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Re: Questions about HV rectifier

Post by Richard Hull »

My system's turbo was killed by a hot internal arc within the fusor. I had more than 10 such arcs over a two week period. None of those hot arcs killed my turbo controller. Number 11 took it out. All items were well grounded. It was some peculiar condition that took it out. Maybe it had enough of my trying to work the wrong fusor. I ultimately completely repaired the turbo controller. The pump, itself, was undamaged. The real solution was to repair the electronics in the controller and get rid of the wrong fusor. No arcs now and a good fusor in rather continuous operation has bred no problems for some months.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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