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Sparkie

Thu Jan 24 2013, 12:42AM

Registered Member #627 Joined: Thu Apr 05 2007, 04:05PM
Location: London
Posts: 32

Hi all!

I have 4 MOT's and am trying to think of the best way to connect them as a PSU for mainly drawing arcs and things. I am thinking of connecting two outputs in series and having each ballasted by its own MOT.

I have drawn a crude schematic to show what I mean.

All cores are grounded, should provide around 4kV. Has anyone tried this or does anyone have suggestions on a different way to do this?

Cheers, John.

Sparkie

Thu Jan 24 2013, 12:49AM

Registered Member #627 Joined: Thu Apr 05 2007, 04:05PM
Location: London
Posts: 32

Actually, the phasing I think is wrong, how about this..

1358988552 627 FT149660 Mot Psu Sparkie 2

Newton Brawn

Thu Jan 24 2013, 12:59AM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

Sparkie 1

Congratulation for precise posting of the circuit and specs of your project !
Most of the threads do not specify the concept and materials, SOOOO it is difficult to provide a precise answer .

I am gessing that the intention of two MOTs connected to the "L" is providing a current limitation, avoiding a line overload.
If so, the secondary of that MOTs as to be without any connection.

I believe that you may use only one MOT as ballast, and two to transform 120V to 2000/4000V

What is your line suppy ?? can you get only 120V ac from normal outlet ??

also, tthe connection beteen "L" and "L" may be seen as a short cicuit between lines....

Sparkie

Thu Jan 24 2013, 01:07AM

Registered Member #627 Joined: Thu Apr 05 2007, 04:05PM
Location: London
Posts: 32

Hi Newton.

Yes, I have tried this with one MOT as a ballast for 2 MOT's in series. Problem is, you double the voltage, but half the current (I think?). I was thinking of the basic one MOT ballasting another kinda setup, but two of them, for a bit more punch. I think this would give double the voltage, but keep the same current as the simple setup of 2 MOT's.

Yes the secondaries of the two ballasts would be shorted, but remain earthed.

I live in the UK, so its 240v line voltage at 13 amps. The 13A is negotiable though lol ;) 'L' is 'Live' and 'N' is 'Neutral'. Not sure what this is called in other countries. There is no short.

Cheers, John.

Newton Brawn

Thu Jan 24 2013, 01:14AM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

Post a new drawing, only the primaries, erasing one of "L", oterwise we can read your power supply outlet as 240-0-240V or 480V between lines.

Regarding the ballast MOTs with the secondary shorted it may work, (taking advantage of the transformer dispersion reactance or stay inductance) I agree with this tipe of ballaasting....

Sparkie

Thu Jan 24 2013, 01:20AM

Registered Member #627 Joined: Thu Apr 05 2007, 04:05PM
Location: London
Posts: 32

Just ignore the secondaries? It's pretty clear :)
It took me all of 2 mins to draw in photoshop haha!

StormInABottle

Thu Jan 24 2013, 03:17PM

Registered Member #9252 Joined: Fri Jan 04 2013, 06:27AM
Location: Andromeda
Posts: 253

I am quite sure 1 mot is pretty enough for ballasting.
use three mots

prim are in parallel
Secs are in series.

With the middle points grounded
So like Lets say we have a + and - wire to make things easier (AC has no polarity)

+ iron core - (Ground and connected to previous) + iron core - (Ground and connected to previous) + iron core -

Use the first and last connections to draw arcs

Also if you are interested in larger arcs put a few mocs in series with the output
With few i mean 4 if you plan for only 2 mots running and more like 6 or 8 for 3 running But for decent results get double the number you planned for
And wire half in parallel
and the other half in parallel
Now you have 2 packs of mocs
Wire those 2 in series. Decent results XD
And those saying ground the iron core is because( i think ) Some mots has the other wire of the secondary connected to the core.

use proper cooling and a fan is welcomed

Be safe. don't touch the arc :P

Newton Brawn

Fri Jan 25 2013, 09:37PM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

Hi Sparkie!

Just ignore the secondaries? It's pretty clear :)
It took me all of 2 mins to draw in photoshop haha!

I have tryed the Photoshop,....and the Paint tooo.
It tooks more than one hour to produce a very poor sketch... I do not have habbility enough to draw free hand with mouse.
So I decide draw with Autocad, it takes 15 minutes.
The Autocad drawing is in .dwg format, that is not so friendly to all people, SOOooo I copy and paste to Windows Paint and save as a .jpg format .
Here the results;

1359149384 3343 FT149660 Two Mots Two Ballasts

GROUND FRON THE POWER SUPPLY TO BE CONNECTED TO ALL TRANSFORMERS CORES

Newton Brawn

Fri Jan 25 2013, 09:51PM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

And why not use a domestic ligth dimmer in the place of the two ballast ???

Wastrel

Sat Jan 26 2013, 11:30AM

Registered Member #4095 Joined: Thu Sept 15 2011, 03:19PM
Location: England.
Posts: 122

Light dimmers tend to be very bad at controlling inductive loads.

What is the rational for shorting the secondaries on the ballasts? What stops them turning into fiery balls of death?

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