Hi I am constructing a project that uses an arduino to turn on and off 3 high voltage power supplies (12v to 20000v) with a 5v relay shield. These are connected to metal plates that create a spark and it makes a kind of beat or music composition using the sound of the discharge. Everything is working great however, these power supplies keep failing? I have had three die on me and I cant figure out why? They work and then all of the sudden stop and start to get really hot. The only thing I can think of is that- A. They are not meant to be turned on and off regularly or - B. I am using 9v instead of the recommended 12v because the output was too strong with 12v. Can you think of anything else?
Please help! I need this to work in a few days. Thanks!! Here is a link to the generators I have:
http://www.ebay.co.uk/itm/DC-12V-to...965775?hash=item3f72ccd38f:g:xbUAAOSw44BYa-Tu

 

If they are intended as ion generators then they may not like being used as spark generators. The spark is effectively a short-circuit on the output.

 

If they are intended as ion generators then they may not like being used as spark generators. The spark is effectively a short-circuit on the output.

Thanks. Hmm is there any way to use a separate negative or positive output to still create the spark without shorting it? I have done this with other ion generators with no problem but maybe these are not as durable? Cheers

 

You could maybe put a resistor in series with the output. The capacitance of the plates would charge up until the voltage gets high enough to make the spark and then be recharged through the resistor. The resistor would have to be able to handle 20kV across it. As to the value of such a resistor, the higher the value the more protection it gives but the slower the available spark rate.

If you know of generators which don't mind being treated this way, why not use them instead?

 

You could maybe put a resistor in series with the output. The capacitance of the plates would charge up until the voltage gets high enough to make the spark and then be recharged through the resistor. The resistor would have to be able to handle 20kV across it. As to the value of such a resistor, the higher the value the more protection it gives but the slower the available spark rate.

If you know of generators which don't mind being treated this way, why not use them instead?

Unfortunately, I can not find the ion generators in the UK and I don't have time to reorder from China. Thanks I am on my last try with these so I hope this works.I will try to find some resistors in time. Do I need to put them on both the negative and positive output? And just to be clear I would hook one end of the resistor to the plate and the other end to the output, correct? Thanks

 

The resistor needs to be in just one wire. Note that you may need several resistors in series to get a high enough voltage rating. Standard resistors are generally rated at perhaps 200V and you would need 100 of those to get to 20kV so it would be more sensible to look for resistors with a much higher rating. If they are similar resistors then you can just add the voltage ratings together.

 

The resistor needs to be in just one wire. Note that you may need several resistors in series to get a high enough voltage rating. Standard resistors are generally rated at perhaps 200V and you would need 100 of those to get to 20kV so it would be more sensible to look for resistors with a much higher rating. If they are similar resistors then you can just add the voltage ratings together.

Thanks I will have a look around now. Hmm I had a thought but I am probably totally wrong. If I put a diode on the ends of the terminal would it not stop the voltage from shorting back into the device? Or even High voltage capacitors on the ends so they discharge and not the device? (I have some of these laying around that,s why I ask) Sorry if its a stupid question.

 

No, the diode won't help at all.

 

No, the diode won't help at all.

OK - One last question. (my knowledge is quite limited) When looking for a resistor do I need to worry about the watts? I know the unit draws 5w of power but does the High voltage output have to be equal to that or is it less? I am finding a few resistors that are 3W. Will this work? Thanks.

 

Hello,

As @AlbertHall said, you can not use standars resistors.
High voltage resistors will look like these:
http://www.ohmite.com/search.php?appl=High Voltage&function=results
http://www.caddock.com/Online_catalog/high_voltage/high_voltage.html
http://www.high-voltage-resistors.com/

Bertus

 

Hello,

As @AlbertHall said, you can not use standars resistors.
High voltage resistors will look like these:
http://www.ohmite.com/search.php?appl=High Voltage&function=results
http://www.caddock.com/Online_catalog/high_voltage/high_voltage.html
http://www.high-voltage-resistors.com/

Bertus

Hi Thanks. I am looking to get these:
http://www.ebay.com/itm/4-x-Holsworthy-electronics-HB03R-500M-ohm-high-voltage-resistors/391714908746?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIM.MBE&ao=2&asc=41375&meid=e0a313e6a94e4c6fbc81e3776b2c2959&pid=100005&rk=4&rkt=6&sd=302361484057#payCntId

The generators I have can be turned down to 15kv so thesemight work but I am just worried about the watts? My generator draws 5w but does it also output 5w high voltage? These resistors on ebay are only 2w will they do?

Thanks

 

Can you measure the capacitance of your plates?

I was thinking about 10MΩ would limit the current surge reasonably. 500MΩ (well, 1000MΩ as you would need two in series, especially as he isn't sure about the voltage rating) might restrict the spark rate too much. It all depends on the capacitance it is feeding.

 

Can you measure the capacitance of your plates?

I was thinking about 10MΩ would limit the current surge reasonably. 500MΩ (well, 1000MΩ as you would need two in series, especially as he isn't sure about the voltage rating) might restrict the spark rate too much. It all depends on the capacitance it is feeding.

Hi not sure how to measure the capacitance? They are 1 mm thick aluminium sheets about 55/70 cm. I now also found some resistors that are 20kv however the watts are only 2.5 would that be ok? Would I need 2 if the voltage of the resister is 20kv? not sure the relationship between Ohms and watts? Or if the resister would burn up if there is a slight discrepancy Thanks.

 

Here is the link to the 20kv resistor:
http://uk.farnell.com/ohmite/sm108031007fe/resistor-20kv-1-gig-1/dp/1550788

 

Hi not sure how to measure the capacitance? They are 1 mm thick aluminium sheets about 55/70 cm.

How far apart are the plates?
Then we can calculate the capacitance.

 

How far apart are the plates?
Then we can calculate the capacitance.

68/555

Sorry it is a bit complicated but I will try to describe it. They are in my school so I don't have photos. the sheet of metal is 68cm by 555 cm resting in a metal frame
5cm thick x 5cm angled 2mm thick aluminium in an L shape the metal sheet rests inside suspended on some wood blocks with a spark gap between the frame (charged positively) and the metal sheet charged negatively. The spark gap is around 1.5mm. Hope that makes sense.

 

Sorry 68 x 55.5 cm for the sheet.

 

Sorry 68 x 55.5 cm for the sheet.

How far apart are the plates?
Then we can calculate the capacitance.

Hi I was able to have someone take photos here is the picture of the frame one is of the front and one is of the back. Also, The width of the frame is 3cm not 5cm. If there is any way you can get back tonight I would really appreciate it. I need the resistor for Tuesday.

Thank you!

 

I don't understand where the sparks happen. Is it between the red line and the green line below?

 

I don't understand where the sparks happen. Is it between the red line and the green line below?
View attachment 130219

Hi yes that is correct. In the gap between the panel and the frame as you pointed out. Cheers!