Question for Oztules.

[Jerry]

I'm intrested in trying some caps on the 14-11 ceramic alt to see if there is an improvement.

Your freind in OZ is using 200UF on the F&P. Is that per phase or per coil?

I will be trying it per coil. The 14-11 is still mounted on the bench test setup so this will be a good time for testing caps.

I don't know what phase class the 14-11 falls under since all coils are indepenant of each other?

I can isolate one coil for testing. Then maybe project testing results for all 11 coils?

DC coil resistance is 6 Ohms. 14 magnetic poles.

                    JK TAS Jerry

[ruddycrazy]

Hi Jerry,

         With the 216uf om my F&P I just conneceted them up in seires with each wild 3 phase output. So  by putting 2 400 volt 470 uf electro's back to back I ended up with non-polarised caps @ 1/2 the value 1 set on each phase . On all the feedback since what I did became public and that was the full intention the caps really shine with a genny with many poles and run at a higher frequency. For you to really try out the cap test as you 'Jerry Rigged' each coil could have caps in series before each of the recifier doides. As far as size of the caps go I'd start @ 200 uf and go up or down to see what the different values come out for each cap rating.

 Now with using caps in series the batteries are isolated from the genny so the genny will run at higher wild Ac.

although this next link is over 21 pages long there is some good reading on the use of caps and I think page 16-17 is a formula to use to size caps.

http://www.thebackshed.com/Windmill/FORUM1/forum_posts.asp?TID=1138&PN=1&TPN=1

most of all have fun testing Jerry

Cheers Bryan

[oztules]

Jerry,

Bryan and Gordon used a series per phase arrangement in the finish. Gordon did some extensive testing using parallel per phase and doubling per phase.

 The link  Bryan suggests says it all really. It's a long long read, and shows conclusively that I still have not got a good fix on whats happening.

Looks like a combination of MMF movement and leakage reactance  and looser coupling to the prop at lower rpm to help keep out of stall are the active ingredients.

Not sure this will help an axial with ferrites (stall unlikely)... maybe the doubler will help pull the rpm down and allow for a slightly bigger prop?

I've been hopelessly wrong with all of this ( as that thread will show), but I will be interested in any development from you regarding caps and the 14-11.

You have managed results no-one expected before, so I have learned to not underestimate your ability to come up with something from left field.  

........oztules

[FuddyDuddy]

You should keep in mind that capacitors are simply filter and coupling devices.

They DO NOT BOOST POWER. I used caps in an AC application many years ago. Fortunally, they were in a steel case. I never did find the meters that were on the front of that panel. Not sure where it blew them.

If you do try the capacitors on the AC side, I'd recommend non-polarized units, suach as are used for motor starting/running. They are designed for AC and have an entirely differnt rating from their DC cousins.

Good luck, and don't stand too close when you energize them.

[Flux]

I got involved in some of the discussion on this but don't want to get much more involved.

There is little doubt that for the F&P motor the use of series capacitors brings a large improvement in results.

This is due to the nature of the beast. It is unlikely that you will see any benefit at all with air gap alternators ( there remains the question of the effect of your iron powder in the coils). Unless the machine shows reactance limiting there is no point in using the capacitors. There may be matching issues affecting the speed/load curve when used with a prop on a wind machine but those effects will not show on a bench test.

With your arrangement with many coils the thing is going to be nightmare to even try it. The capacitor values will be high and you need one series capacitor per coil.

The values are so large that you will be forced to use electrolytics either of the motor start type or dc capacitors back to back. The long term stability of either on ac loading is questionable but that wouldn't prevent you trying the tests.

I also have witnessed spectacular disintegration of capacitors so take suitable precautions.

Flux

[gizmo]

Yeah I have to agree with Flux on this one.

The research into caps on F&P's is still in early stages, its on going research. We know a 100 series F&P, wired in delta, with series caps, feeding a 24v system, gives big gains in efficiency and power matching to the turbine. If you run a 24v system, its the best configuration to use. But for 12v or 48v there are no recommendations yet, just a few suggestions. Like I said, its on going.

I dont think there would be much to gain in a axial flux design where the alternator power pretty much follows the turbine power with RPM.

There may be gains in the motor conversions, or earlier Volvo disc brake alternators, anything with a lot of iron, but like Flux said you will need some serious caps for these low Hz alternators.

Caps can explode with a hell of a bang. Never put your head above a cap, and wear safety glasses. On bigger caps you will see a couple of crossed groves on the top. These are designed to peel open when the pressure builds up, stops the things going off like a grenade. But a cap will still spray out a mess of paper, aluminum plate and electrolyte with a lot of force, noise and smoke. They can take your eye out!  

Glenn