Simple to make Hilden-Brand style motor

[i_ron]

Hi, don't 100% understand the arrangement right now. Circuit logic and coil params would help: wire, no of turns, inductance, resistance.

There are two side by side coils on the top bar and two on the bottom.

One top and one bottom wired in series.

Reverse phase connected so each set low side driven.

But they interact detrimentally....lol

not to worry ... will go to an H bridge

Ron

[scianto]

There are two side by side coils on the top bar and two on the bottom.
One top and one bottom wired in series.
Reverse phase connected so each set low side driven.

I used this one:
http://servilo.website.pl/laboratorio/esploroj/rownolegle_strumienie/SRSM2i3_sterowanie_rys1.png
to switch the coils on PPMM
and it did not perform as good as this one:
http://servilo.website.pl/laboratorio/esploroj/rownolegle_strumienie/SRSM2i3_sterowanie_rys12.png
The second circuit gave higher overall efficiency.

[i_ron]

I used this one:
http://servilo.website.pl/laboratorio/esploroj/rownolegle_strumienie/SRSM2i3_sterowanie_rys1.png
to switch the coils on PPMM
and it did not perform as good as this one:
http://servilo.website.pl/laboratorio/esploroj/rownolegle_strumienie/SRSM2i3_sterowanie_rys12.png
The second circuit gave higher overall efficiency.

Welcome scianto!  good to see you posting here too.

I am still a few steps behind you on this, lol.

On your first schematic I see the two coils paralleled but driven separately on the second schematic, so not clear if we are on the same page here?

What I suspect is happening with the four coil setup is the collapsing flux is generating a potential in both pairs. The diode recirculates this spike in the pair just powered but induces an opposite polarity in the unpowered pair which causes the fet to be powered before the pulse arrives, sound good?

I had looked at the hip4081 but was nervous about the possible shoot through on power up... the MC33035 I haven't looked at yet. Trouble is all these new chips are only available in surface mount, so I am kind of partial to the old chips.

Anyway thanks for the schematics to this list. I have some of yours already from other lists. I like your work!

rgds, Ron

[Nali2001]

Hmm I guess one coil is causing induction into the other via normal transformer action. And the diode is providing an easy current path, or a dead short 'load'.

I too had the idea not too long ago to use two coils like you do, but I dropped the idea because I expected cross feeding and them loading each other.

So I guess you will be doing a half- or full bridge next?
Problem with the half bridge is that you only get to use half the voltage your power supply puts out. Since you make a floating ground.

Other problem with these bridges is that since the polarity now is bi-polar you can not use a diode to capture the fly-back.

[i_ron]

Hmm I guess one coil is causing induction into the other via normal transformer action. And the diode is providing an easy current path, or a dead short 'load'.

I too had the idea not too long ago to use two coils like you do, but I dropped the idea because I expected cross feeding and them loading each other.

So I guess you will be doing a half- or full bridge next?
Problem with the half bridge is that you only get to use half the voltage your power supply puts out. Since you make a floating ground.

Other problem with these bridges is that since the polarity now is bi-polar you can not use a diode to capture the fly-back.

Steven,

You got that right, two adjacent coils can be a problem.

Looking at H bridge pre drivers and the only one available it seems is the A4940, still only in surface mount but looks like a winner. Looked at dozens of others but no stock anywhere, let alone my two favorite suppliers... Digikey and Newark.

Another bit of info for the group, I was in touch with sales at Ed Fagan and
Vimvar costs $30 a pound. a 2 foot bar of 1 1/4 inch dia weighs 9 lbs, so would cost 275 dollars, plus $25 handling, ...plus shipping......wow

Ron

http://www.edfagan.com/vim-var-core-iron-rod.php