3 Phase HVDC supply with MOTs / Projects / Forums

Forums

4hv.org :: Forums :: Projects

« Previous topic | Next topic »

3 Phase HVDC supply with MOTs

previous 1 2 3 4 next

Move Thread

LAN_403

Arcstarter

Sun Apr 05 2009, 06:55PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

That was CRAZY! Ohh, nice :). *imagines people touching it and exploding limbs flying everywhere*

I like that last pic on the last post, looks like your about to say "WHAT?!".

Zum Beispiel

Sun Apr 05 2009, 09:12PM

Registered Member #514 Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295

That is brilliant! You know you're playing with power when the arc is longer than your chicken stick.

Just, wow.

Firefox

Mon Apr 06 2009, 04:04AM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

90kVA? That is insane, no wonder your MOT blew up. Even assuming theyre 1.3kW MOTS, you're burning six times the current they're designed for through them! I hope you have three spares. :)

Kizmo

Mon Apr 06 2009, 07:09AM

Registered Member #599 Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624

Cant blame transformers being weak, 2x insulation stress and 5x rated power.

Output was 70-80kVA. When drawing arcs output voltage decreases by few kV.

Got new idea which involves 3 phases, 3 x motstacks, 3 x fullwave CW doublers and single HVDC output

EDIT:

Did some quick copypaste paint art:

I could ground every single mot core and secondary like they are designed to be used. With fullwave CW and 3 phases ripple shouldnt be problem without very large capacitors.. (just 4-5ÂµF should be fine)?

Renesis

Mon Apr 06 2009, 11:29AM

Registered Member #2028 Joined: Mon Mar 16 2009, 08:13PM
Location: Norway
Posts: 319

Impressive project, i would blow my main fuse at 2/3 of that power. Who needs pole pigs?

With fullwave CW and 3 phases ripple shouldnt be problem without very large capacitors

It is possible to build 12 pulse rectifiers u know, they produce less ripple. By using transformers with both star- and deltaconfiguration you get a 30% phaseshift, like this:

Firefox

Mon Apr 06 2009, 05:19PM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

You can also do a six phase rectifier with a single load stack. For the six secondaries, just use your MOTs balanced around ground with the primaries antiparallel, just like you have been. Note that the output voltage is only two times peak voltage of one phase, not two times the voltage across the two secondaries 180 degrees out of phase from eachother.

rp181

Mon Apr 06 2009, 09:56PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

That is amazing. I hope nothing [life threatening] goes wrong. May i suggest some UV protection?
Good luck.

Addi

Sat Apr 25 2009, 03:36PM

Registered Member #1268 Joined: Sat Jan 26 2008, 06:12PM
Location: Middle Germany
Posts: 3

@Kizmo:

Have you used any Balancing-Resistors in parallel to the Diodes? How much Diodes have you used ans how are the exact names of the Diodes?

I am asking, because I tried to rebuild you Stack in the last few days. My Rectifier consist of 120P600M Diodes (1kV/6A each). With only three MOTÂ´s (5kVDC out) I got about 60-70cm Arcs today. But after a few second, it fried two of six Diodestrings (20 Diodes each ---> 20kV / 6A). I used an Inductor (about 100Windings of .8mm Wire) and about 3nF as an Lowpass-Filter on the Output. Do you use any filtering?

Thanks for your help.

Kizmo

Sat Apr 25 2009, 05:38PM

Registered Member #599 Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624

My rectifier is made from 90 P600M diodes (1kV 6A)

Each 'diode' in my 6 pulse rectifier is made from 15 diodes in series (total 15kV 6amp) and they worked very well even @ crazy power levels (nearly 100kVA from wall)

I dont use any sort of filtering or balancing resistors.

EDIT:

I got very excited about pulling high power arcs and now i got myself 30kVA 3ph 0.4/20kV distribution transformer. I think it can do 100-150kVA in short runs without problems.

Coherent

Mon Apr 27 2009, 05:38PM

Registered Member #1886 Joined: Sun Dec 28 2008, 02:55AM
Location:
Posts: 73

Kizmo wrote ...

My rectifier is made from 90 P600M diodes (1kV 6A)

epic

Where did you get a substation transformer...?

previous 1 2 3 4 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob