The Master Of Magnetics "Steven Mark"

[Jdo300]

Hello All,

I just thought I would pop up for a bit to give you some new (and hopefully helpful) information to assist you in your TPU experiments. I've written an article titled "Phase Relationships and Harmonics in the
Steven Mark Toroidal Power Unit" which will help us to understand how short pulses, out of phase transformers, and harmonics all contribute to the effects exhibited by the TPU. This document is by no means complete or the authoritative explanation but it is based on some recent experiments I have performed. Comments welcome .

God Bless,
Jason O

[BEP]

@Jason,
Thanks.

This reminds me of emegency power plant problems. When paralleling two or more 3 phase generators to a bus the neutral connections were always a major concern. As long as the generators were matched (same sine shape and 1/4 wave width) there was only a concern of matching voltage and phase. As long as those two were good little neutral current would flow - unless the load was unbalanced.

When two different name-brand sets were working together sine shape and 1/4 wave width was so much a concern that sometimes the neutral link had to be disconnected to prevent cross current. Cross current detracted from the load handling performance. This was usually because during manufacture the stator windings were not wound at the same pitch.

As for harmonics: I used to perform Mil standard 705B and C testing of power plants. Harmonic value recording was one of many tests. For a 60Hz system you would expect the second to be 120 and the third to be 180. They were not. The second was usually around 108 and the third about 195. There were components at 120 and 180 but were very small compared to the others.
On systems that had unusually high voltage harmonics the voltage between neutral and ground could easily exceed 200VDC with a heavy AC component. This would be on a 3 phase 480/277 WYE 60Hz generator. A generator with these results would have failed the military standard testing and be rejected.

[Jdo300]

Hi BEP,

Thanks for sharing that info with me! One thing I'm wondering is if an increase in neutral currents reflects as increased draw from the three-phase source? Or are the neutral currents basically *free" because of the harmonics? Also you mention that they were DC with a heavy AC component? That is interesting, getting DC from three-phase AC...

The fact that the harmonics are not mathematically consistent reminds me of the musical scale, which doesn't follow the mathematical logarithmic progression of harmonics. According to this source here: http://redwood.berkeley.edu/bruno/psc129/handouts/logs-and-music/logs-and-music.html to get the frequency of a note that is one-half step higher, you multiply the first note's frequency by 1.06. I think that we need to take the musical scale into account when determining the harmonics we want to use and your example is proof of that.

God Bless,
Jason O

[MarkSnoswell]

Hi all,
   Well I am rapidly running out of time -- I'll be in the US for most of next month. For those of you who think I do mostly theory and graphics I gathered up some of the coils I have lying around and took a couple of photos... sorry no photographs of the really interesting coils

The elaborate coils in the benchtop collection are 1 and 3 phase counter wound coils.

cheers

Mark S.

[Super God]

Your title should be "Super Coil Winder"  Those are some neat and impressive coils there!