Author Topic: Need some safety advice.  (Read 3063 times)

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Offline makermanTopic starter

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Need some safety advice.
« on: August 31, 2023, 09:22:47 am »
Hi, i've been doing experiments with high voltage, 2-plate  capacitors that exhibit a net thrust in one direction when charged.

I was using those cheap ebay HV units that can only be on for a few sseconds and die if on for too long, so i shopped around for a mroe reliable HV source.

I ended up ordering this (it should arrive soon) :

https://www.ebay.co.uk/itm/374582175842

Instructions from the seller :

1, connect the high voltage output line to the required load (high voltage electric field), the red line is the high voltage positive pole, the black line is the high voltage output negative pole; the positive and negative discharge distance should be less than the specified distance, while the power supply must be connected to the load before energizing; so as not to damage the power supply. Please pay special attention!!!

2、Close the protection circuit and rotate the protection potentiometer to the left to the off position.

3, connected to 220V AC voltage, press the power switch, the work indicator (green) lights up, while the high voltage indicator (red) lights up. At this point the power supply begins to output high voltage; adjust the voltage adjustment potentiometer to select the required voltage; for firing protection please rotate the protection adjustment potentiometer to the right (clockwise) to the high voltage indicator (red) flashing state, then to the left (counterclockwise) back to the red light is always on position, (in the process of adjustment note that the potentiometer should be rotated slowly, do not rotate too fast.) At this time, if the output side of the fire, the power supply will cut off the high-voltage output; delay 1-2 seconds to restart; can also be designed to protect the restart time according to customer requirements.

Not yet sure how to 'close the protection circuit', and also a little worried since it requires mains AC input.

Will it cause much EMI ?

Are there any other safety concerns (aside from the usual HV protocols) ?

Thanks if you can advise.


 
 

Offline jonpaul

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Re: Need some safety advice.
« Reply #1 on: August 31, 2023, 09:27:38 am »
dangerous junk from China.

Suggest to stop the purchase and lear about HV safety first.

Also research electrostatic attraction, it is VERY low forces unless plates are hughe and V of 30..500 kV.

Jon
Jean-Paul  the Internet Dinosaur
 
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Offline makermanTopic starter

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Re: Need some safety advice.
« Reply #2 on: August 31, 2023, 09:33:31 am »
 
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Offline rstofer

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Re: Need some safety advice.
« Reply #3 on: September 02, 2023, 12:08:37 am »
The safety circuit interlock might be microswitches on the doors of the safety enclosure.  Clear Lexan or acrylic comes to mind.  You were going to enclose the experiment, right?
 

Online dietert1

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Re: Need some safety advice.
« Reply #4 on: September 02, 2023, 06:36:03 am »
What wants to be a scientific paper isn't very convicing to me. They claim that the weight of a 62 g capacitor changes by about 0.3 to 0.6 g, an easy to observe effect that should be well known - but isn't. How is the eletronic weight scale affected by the HV setup? Something easy to test, yet missing.

Take care with that HV generator board. I'd rather recommend using a Spellmann high voltage supply. We have a small SL50PN10 (50 KV 0.2mA) unit and it's well made and safe. There is a special HV cable and a manual - as far as i remember including schematics.

Regards, Dieter
« Last Edit: September 02, 2023, 06:43:15 am by dietert1 »
 

Offline donlisms

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Re: Need some safety advice.
« Reply #5 on: September 02, 2023, 03:51:32 pm »
Think of yourself as being part of the circuit.  Electrons go where *they* want, not necessarily where *you* want. Please don't die. 
 

Offline MrAl

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Re: Need some safety advice.
« Reply #6 on: September 02, 2023, 04:06:43 pm »
Hi,

Should ask the seller, probably just a language translation issue.
 

Offline tridac

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Re: Need some safety advice.
« Reply #7 on: September 02, 2023, 04:59:12 pm »
Looking at that, the claims about 300 watts and 10 mA sound a bit optimistic. Would expect less than 1mA output current max continuous. The transformer looks  like a tv style crt final anode flyback transformer, which usually run in the low to medium microamp range. May work for experiments, but not for long term use, other than for < 1 mA output.

Key thing on safety is to ensure the common side of the output is properly earthed (grounded) and never use a single wire or floating output feed. 30Kv will look for any way to find a path to flash over. Easy way to ensure that is to use RG8 solid coax to ensure that a gound, as well as HV, is carried to the experiment. Make yourself a shorting / discharge stick, with a grounded clip at one end, insulated prong at the other, and keep output shorted when not powered up. Never take chances with HV, as your life could depend on it. Recently restored a Fluke 410B for the lab here and did get a couple of zaps in the process, really should know better etc. Only goes to 10Kv, but iirc, they made a 30Kv version as well, as did other vendors. Pic shows an output box and 10000:1 divider, so it could be calibrated. Good hv connectors are hard to find at 30Kv and expensive, but Ebay can help...
Test gear restoration, hardware and software projects...
 

Online dietert1

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Re: Need some safety advice.
« Reply #8 on: September 02, 2023, 06:39:37 pm »
Yes, our Spellmann unit also uses RG8 with a N-Type connector, see image.

Regards, Dieter
 


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