I needed a variable 0 to 50KV high voltage power supply for my high voltage experiments that wouldn't break the bank, so I built my own.
With just a few parts from old microwave ovens, TV sets, and an oil burner, you can build an affordable instrument for whatever you wish to snap,crackle, or pop!
The key component is the voltage multiplier, which I covered in the High Voltage Multiplier instructable. Build it first, then drop it into this project for a variable output.
With just a few parts from old microwave ovens, TV sets, and an oil burner, you can build an affordable instrument for whatever you wish to snap,crackle, or pop!
The key component is the voltage multiplier, which I covered in the High Voltage Multiplier instructable. Build it first, then drop it into this project for a variable output.
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Signing UpStep 1: Theory of Operation
The diagram shows the supply in the de-energized condition and the case closed.
Mains voltage is applied to the power supply thru a 120 VAC Panel connector. With the case closed, current passes through a 5 Amp fuse, F1 and through the case safety switch, S1 causing the Ready indicator, I1 to light when the power switch S2 is placed in the ON position to energize the supply.
At this time, the power supply is NOT ON but in a state of readiness to enegize the high voltage stage.
When pushbutton S3 is pressed, relay K1 energizes and remains energized after S3 is released.
Current passes through Variac, VT1 which adjusts the input voltage to the OBT. The OBT steps up the input voltage to a maximum of 6,000 VAC. The output of the OBT is fed to the high voltage multiplier, HVM where it is multiplied to 51,000 VDC output.
To de-energize the supply, place S2 in the OFF position. K1 will de-energize and remove power from the OBT and HVM and all indicators will extinguish.
The case safety switch and the power contactor are not necessary for this supply to work. I thought the ability to power on and off by using a pushbutton was cool. Thats all. The second schematic shows them removed.
Mains voltage is applied to the power supply thru a 120 VAC Panel connector. With the case closed, current passes through a 5 Amp fuse, F1 and through the case safety switch, S1 causing the Ready indicator, I1 to light when the power switch S2 is placed in the ON position to energize the supply.
At this time, the power supply is NOT ON but in a state of readiness to enegize the high voltage stage.
When pushbutton S3 is pressed, relay K1 energizes and remains energized after S3 is released.
Current passes through Variac, VT1 which adjusts the input voltage to the OBT. The OBT steps up the input voltage to a maximum of 6,000 VAC. The output of the OBT is fed to the high voltage multiplier, HVM where it is multiplied to 51,000 VDC output.
To de-energize the supply, place S2 in the OFF position. K1 will de-energize and remove power from the OBT and HVM and all indicators will extinguish.
The case safety switch and the power contactor are not necessary for this supply to work. I thought the ability to power on and off by using a pushbutton was cool. Thats all. The second schematic shows them removed.
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Member Machine mentioned earlier that a front panel meter would be nice and I agree. He had some concerns about using a voltage divider so the meter could work with some reasonable voltage like 0 to 10 V instead of 0 to 50 kV. I've done the resistor voltage divider thing successfully at 50 kV using a 5000:1 voltage divider. I then connected the divided voltage output to an analog DC voltmeter calibrated to 0 - 10 V.
One final comment. I plan to use a 3PDT relay for K1 so the third pole can be used to discharge the HV output through an appropriately sized current limiting resistor. I plan to connect the HV output to one end of the resistor and the other end of the resistor to the common of the third pole on K1. The NC contact of the third pole goes to ground. Whenever K1 is not energized, the HV output is routed to ground through the current limiting resistor.
Do you see any problems with any of the above enhancement assuming I use appropriately rated components and good HV insulation practice?
This device is for sale. If you would like further details, please contact me at burningsuntech@gmail.com
- BST
This is a HIGH VOLTAGE power supply and cannot be used to power a house which is low voltage (120 volts AC). This is also a low current supply (20 milliamps) and a house requires high current (200 Amps). So, no. This will not suit your needs.
-BST
thank you very much
It'd be hard to measure directly the output volts as a high-voltage divider would be needed (more cost, insulation difficulties).
So a meter calibrated in kV but measuring the output volts at VT1 would be an easier method to indicate final voltage.
How can you make it -50 wrt earth ground? This will allow it to be used as a negative ion generator.
Automatic trans fluid is supposed to work well and it has an operating temp of well over 100 deg F.
An aluminum housing with heat sink fins (or even tubes) with air being circulated over/ through them. H2O running through external copper tubes and then into a heat exchanger (auto heater core or ac condenser) would improve your coolin effect also. This could lead to more efficient over all operation. (water cooled TIG torch??)
Great Instructable!!!! please keep it up.
Possibly. As to specifics, I can't say. Most likely, you will be using 1N4007 diodes for the diodes. And caps will be .001ufd 2 KV minimum, but any voltage up to 10Kv will be fine.
There has been a lot of questions concerning the math I used to figure out the voltages. So I will refer you to the link that I found concerning Cockroft-Walton Voltage Multipliers.
http://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generator
And here is a blurb about the output voltage characteristics of the multiplier:
http://www.allaboutcircuits.com/vol_3/chpt_3/8.html
Good luck in your build.
RA
Wanting to use this for part of my science fair but I do not need to go over 6000 volts.
If you only want 0 to 6000 volts AC, then the answer is yes.
If you need 0 to 6000 volts DC, then you must add a single 12KV Diode to the output of the transformer.
Good Luck in the science fair.
RA
without knowing details like how much current you want the device to provide and at what voltages, I wont be able to help.
More info is needed besides "can I modify your design to achieve this goal?"
RA
The device does not need to provide any current. I only need to provide variable voltage potentials between 100-700 VAC. I am attempting to create a voltage calibration set for my BMI 8800 power disturbance analyzers.
The required voltage (Vrms) calibration levels are:
1. 0
2. 7.6-8.4
3. 30.2-33.4
4. 75.5-83.5
5. 150-170
6. 200-225
7. 300-335
8. 604-670
I am using a 0-140VAC Variac to produce the first four levels.
I tried using a hipot tester to produce the last four levels and was successful up to level 8. The hipot unit that I own is a Hiptronics HD5 0-5KV at 5 mA.
The impedance of the BMI voltage input channels during calibration is 1.01 Megga Ohm. At approximately 500 VAC the leakage current light was glowing and the unit was vibrating and ready to fail on leakage. My Hipot tester would need to have at least a 20 mA output capability in order to complete the calibration series
With a vernier dial on the Variac, you would have a calibrated settings range. If you need finer settings, say in millivolts, you would need a twenty-five turn vernier instead of a ten turn vernier.
Hope this helps.
RA
You could use a switch to select one of two ranges. The first range would be what is supplied by the Variac. The second range would be addition of another step-up transformer connected to the output of the variac.
With a Vernier knob attached to the variac and a volt meter, of course, you could tune the output of the step-up transformer to the appropriate ranges based on where the vernier is set.
That would give you your ranges and the desired voltages though it might be a bit cumbersome.
One other possibility would be to calculate the output of a transformer given the input voltage and the number of turns on the output. If you are adventurous enough, you could design and wind your own transformer for the desired output ranges beyond the output of the variac and use a selector switch to select the output tap for the given range you desire.
It takes some doing and a bit of knowledge of transformers but it can be done.
Lastly, you could also have a special transformer built for this purpose which would give you all the ranges based upon which tap you choose.
There are other methods but I do not build devices for people nor do I have the time for these projects as i am currently busy running a business.
Good luck. i hope this helps.
RA
Do you have any suggestions? Any help would be greatly appreciated.
Thanks in advance
Simon
I don't have an six KV Oil Burner Transformer, but I do have a five KV Neon Sign Transformer. Would that work just as well?
Yes it will. In fact even AC (mains) passed thru a standard transformer (ie 120VAC in and 120VAC out) will give you a high voltage based on the formula in the multiplier design. Thanks for the 5 STARs. enjoy the build.
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sometimes spark occured between them.
especialy some closest pins with ground pin.
one of pin closest is also draws purple spray, but never spark