home made pm, low voltage

[meltdown1a]

I just made a pm generator, it has 9 coils 80 windings of #15 spaced in a circle inside a 12" diameter.

I have a board with 12 rows of magnets. this is turned by a Savonius.

With all of the coils hooked in series I'm getting about 2v at around 200rpm.

I got it up to aout 1500 rpm and I still only got about 8v.

I have put washers under the coil to help draw the magnetism though the coil. I have 2 steel plates coming to replace the wood rotor.

It seems that I have all the coils in phases although I had to reverse the three a phase when hooked in series and it seems reversed again when running 3 phase.

Should I proceed with these items or just start over. any Idea's will help

 

[RonMar]

Some Questions:
What kind of magnets?

How much space between magnets and coils?

Actual size of coils?

Size of magnets?

Have you measured the output of a single coil at any RPM?

What did you use to insulate the wire in the coils?

How are the magnets orientated to the coils?

A picture might answer most of these questions.

A combination of coil, magnetic field and ammount of time the field is exposed to the coil determine the output voltage. The wire gauge/diameter usually determines the current capacity out of the coil, to the extent the fixed magnetic field can maintain the voltage under an applied load. The magnets in close proximity should enhance the applied field, so closer spacing should = more voltage. IF the field is not orientated properly to the magnet, it may be receiving a weak field. If the coils are internally shorting, you have effectively a coil with fewer windings, so less voltage output. It the coils are wired incorrectly, the output of one coil could be cancelling out another. A second plate with another set of magnets(coil plate sandwitched between magnet plates) will enhance the field.

Did you design this yourself, or are you following some plan?. IMO, following a proven design with proven components is the best way to build your first one... The Otherpower forum has a wealth of information on this type generator. This is a video of one of my favorites. They also did one on a listeroid slow speed diesel.
YouTube - Otherpower Steam Generator

How did you make your rotor/turbine? i havn't heard anything about a savinious(sp?) rotor in a long time.

Good Luck

 

[MossRoad]

Pardon my ignorance, but what is a pm generator?

 

[RonMar]

PM= Permanent Magnet. Uses fixed high density magnets to generate the magnetic field instead of using some of the generated power to build a magnetic field in a rotor like a traditional alternator/generator.

Not using this power for the field means greater generation efficiency. But since the field is fixed, there is no control of output voltage other than the construction of the generator. Most people use them for wind and hydro where the power source can be unpredictable anyway, and convert it to DC. The DC is then regulated and used to charge batteries, or sometimes back feed the grid via a grid tied inverter...

 

[MikeD74T]

meltdown1a, I've no experience making a PMG but have printed these www.scoraigwind.com/pmgbooklet/itpmg.pdf plans & it's on my to do list. There may be something here that helps. Please post your solutions as you find them. MikeD74T

 

[meltdown1a]

Here are some pictures and details of my project. Since using the steel plate and double the magnets I have raised my voltage by one and a half volts to a whopping 3.5 volts

Go Solar Canada And Wind To. Any advice will be appreciated.
Thanks
Dan

 

[MikeD74T]

Dan, Did you look at the troubleshooting section of the Piggot pdf? It seems to suggest that coil tightness & placement, as well as # of turns /wire size, makes a big difference. They're saying you should see 4 vdc at 60 rpm. What reference are you building from? What are you using for magnets?

I've got a nice brook on my property so am looking to build a raft mounted paddle wheel with a PMG driven initially by a 10 speed bike gears & chain until I find optimum speeds. MikeD74T

 

[tommu56]

In the electically theory you would have to series the windings to increase the voltage if all the magnets and coils are in correct phase and physical relation. but that would also reduce the current.

tom

 

[BrentD]

Ok, here's a few things I notice... First, since you have 3 square magnets in a row for each "magnet" you would be better served to have 3 rows of smaller coils where each magnet passes above one coil.

Second: Not sure of your magnet phasing from the picture, but going around the circle from any arbitrary point the magnets should be N-S-N-S, etc so that each other magnet is flipped relative to the next one around the cricle. The idea is never to have two magnets next to each other with the same pole facing up. This will mean you need an even amount of magnets.

Third: Those look like awfully small magnets, and the washers under the coils aren't going to do much. I would suggest using a finer gauge wire and winding a bunch more turns and wind them around a thick bolt, section of steel rod or rebar (or ferrite core if you can find it). The idea of having a ferrous metal core to a coil is to concentrate the magnetic flux within a smaller diameter and get more field lines passing through each coil.

Have a look at this project Hamster-Powered Night Light for more ideas.

 

[RonMar]

I think your magnets are way to small for those coils. Just like the same reason a conventional generator has low voltage, not enough field is being generated. In the ones I have seen the internals of, the magnet face area is easilly as large as the coil. The field those small magnets are creating is just not large enough to induce much in the coils. Here is a link to some more detailed pics of the otherpower steam engine PMG being built. Note the size of the magnets in relation to the coils. This PMG also has a magnet disk on either side of the coils. More field = more voltage.

Steam powered Generator