Need help with windmill alternator amps problem

[GBillerty]

Hello!

Here is what I made last night:

Disc brake rotor with spindle, stator made from wood with no laminates.

16 Magnets and 8 coils ( 18AWG 50 turns )

NOte: I dont need lot of power, I would be happy to get 2-10 amps.

The problem:

At around 300 RPM, I'v reach 16 Volts and only 0.6 Amps!!!

Maybe the problem is  that don't know how to mesure Amps with my multimeter?

Connected black on COM and red on 10A, selector at 10 (alternative current).

Connected in serial all coils and when I measured that Amps, I had felt the torque on the alternator that moved from the table!!!

Any idea!

thanks a lot...

[iFred]

Since you hooked the coils in series, I would say there is no brake in the coils or wires if you felt the resistance.

Do you have 2 rotors with magnets or just one?

Could be cancellation as well. Check the output and report a single coils output.

[RatOmeter]

As Fred said, check the output from individual coils.  If you connected all coils in series for your measurement, you are almost certainly seeing cancellation.

Also, most multimeters have a seperate jack/hole in which the '+' lead is supposed to be connected for current measurement.

[edy252]

if i got this right: u connected the the ammeters' wires to the wires coming out of the pmg......the resistance of an ammeter is very low, so it's better if u attach a higher resistance and put the ammeter is series with it (that's how u should use an ammeter).

[edy252]

i posted this b4 but wasnt able to see it...so ill post it again

if i got this right: u connected the the ammeters' wires to the wires coming out of the pmg......the resistance of an ammeter is very low (that's why u felt the torque), so it's better if u attach a higher resistance and put the ammeter is series with it (that's how u should use an ammeter in the first place). i learned this the "hard" way ... attached an ammeter to a 220vac output ....got a nice loud bang

[Ungrounded Lightning Rod]

Disc brake rotor with spindle, stator made from wood with no laminates.

Did you put a corresponding second rotor behind the coils?  Even if you don't have magnets on it you need something to return the flux.  Otherwise you'll have a gap of several inches rather than a fraction of an inch.  (Of course putting magnets on the second rotor will about double your voltage and your current, for about 4 times the power.)

Second rotor should co-rotate with the first.  Otherwise you lose power heating it with eddy currents.  (Use care lowering it into position - the magnets will try to grab it and crush your hands.  See other posts about jacking it down with nuts on threadded rods and other assembly approaches.)

Alternatively, back the coils with a flux return path - preferably laminated, oriented so the laminates are edge-on to the field and aligned with its movement, so the filed "slides along the razorblade" as the magnets turn.

Also:  You say "wooden stator".  Did you put the coils in cutouts or on top of the wood.  (Wood thickness also increases the gap, reducing the flux.)

[hiker]

sounds like a single phase alt...

what size are your mags? and what type?-ceramic or neos-

sounds like your using small mags--i would go with at least 85 turns -using that

size wire= more volts at a lower rpm...are your coils wound clockwise then counter

clockwise for the next-and so on?---you can wire them all the same direction..

but when you go  to hook them up make sure they read clockwise and then counter clock

wise......just hook the coils to a batt, when your hooking the ends togeather..then place a magnet over each coil --it should atract on the first coil then repell on the second coil--and so on...........................................................

[jacquesm]

Make sure your amp meter can measure AC amps ! Your 16 volts looks pretty decent, and I would expect a higher current at that voltage (a few amps), if you had a big cancellation problem you would not be seeing the 16 volts...

Another good thing to check is the resistance of your coils, at .6A with a 16 volt output you should measure about 26.5 Ohms resistance in your coils (which would be wildly high !) #18 50 turns, 8 times = 400 turns should not be nearly that high.

It's not 'alternative current', but 'alternating current' !

best regards,

 Jacques.

[GBillerty]

thanks to all!

I have only one roto with neos magnets

Magnets are 1" diameter, 5/8" thick

one coil gave me 2 Volts and 0.6 Amps at arount 100 RPM

connected the ammeter in serie with a 12V DC bulb

the bulb lighted up... rated 10A, started to light up at 4V

all connected on a brigde rectifier.

I'm totally confused

[iFred]

So there it is!!!

as I stated...a single rotor, no magnetic return path... and cancellation

No confusion from this direction, this is normal!

You need either to complete the magnetic path, meaning another rotor with more magnets or a laminated iron after the core (your coils). goto www.otherpower.com, take a good look and read what them have done with single rotors if that is your intention. If your intention is a dual rotor, the still go to www.otherpower.com click on the wind link below and read to gain some basic knowledge on how these things work. As far as cancellation goes, Try rotating the rotor and as you do so, hook up a coil to another coil in series (oh, i don't know, try the 3rd one!) and see if everything increases (volts, amps), then leave that pair and continue hooking in series to every 3rd all the way around in series (if it increase the hook in series, if it decreases in volts or amps the do not hook it up). Then start on the second group and so on. Above all and very first thing, goto http://www.otherpower.com and learn some basics!

I wish you the best!

[hiker]

are your mags stacked or do you have 16 mags spaced around on one disk?

how are your coils laid out'[for single phase]?

if so take 8 of your mags off the disk.

and have the rest evenly spaced .

or use the other 8 mags on a second rotor--for more power!!

for single phase its 8mags--8coils..single rotor

or add the remaining 8 mags to a secound rotor--for a dual rotor setup.....

what size are your coils--is the hole in the center the same size as the mags?

seems to work better that way..

take a look at my minnie mill stator--6 coils and 12 mags..6 mags for each rotor..

coils are run--clockwise then counter clockwise for the next[thats the way the wire is wound on the coil]

or just flip every other coil over if all are wound the same way..n-s-n-s

and like i said use a battery hooked up to your coils to see if each coil is hooked up right..just hold a mag in your hand and see if the mag is pushed away or pulled down over each coil---it should pushaway then pulldown as you go over your coils..

well thats about the best i can explain it for a single phase setup...

ps-- make sure your mags are laid out-n-s-n-s and so on..and again just hold a mag in your hand to verify this--and run it over the top of the rotors that have mags attached..

[GBillerty]

OK I'll try to reduce the gap and add laminates....  but I really dont know why I can't get that amps!

[Flux]

8 coils with 16 poles seems a strange combination. At best you can only get single phase.  Any pictures of the set up would be useful or details of coil dimensions.

You seem to have good voltage so the coils are most likely the right relative size.

The lack of a return path for your flux will not be helping but even so it ought to give an amp or two with that size of wire.  I am not really sure what current you are measuring, short circuit current or current into a lamp load, The only real test is to rectify the output and measure the current into a battery with the meter set for dc amps.

If you want to change things the best thing would be to use two rotors with 8 magnets and use 6 coils 3 phase.  The other option is to keep it 16 pole but use another rotating disc with no magnets and use 12 coils 3 phase. Keep away from single phase it has no virtues at all.

Flux

[Flux]

Just re-read your post. If it will light that lamp that you say is rated at 10A you must have significant current, I think there is something wrong with your meter or with the way you are using it.

Connect the meter in series with that lamp and a 12v battery with the meter set for dc amps and make sure you can get it to read.

When you are happy that the meter is working go back to the test with the alternator rectified and feeding the battery, I bet it is working and you will feel the resistance to turning when you get above cut in speed.

Flux

[GBillerty]

OK!

I'll try using laminates...

I will also try an other multimeter or ammeter with kind of "pinch" a tool like that!

sorry for my english writing

I'll post a update tomorrow

[DanB]

"Maybe the problem is  that don't know how to mesure Amps with my multimeter?

Connected black on COM and red on 10A, selector at 10 (alternative current)."

I wouldn't totally rule that out yet!  You didn't make too clear how your meter is wired up there...

It kind of sounds like you might be hooking the meter directly (both leads) to the alternator?

The meter needs to be in series with the load, so... find your load (a battery, lightbulb or whatever is appropriate) and then it will tell you how much current is flowing.  If you hook it directly across the alternator then...  your reading means very little.

[Beecharmer]

As stated in an earlier post you seem to be having trouble using your multimeter.

To re-iterate.

Most multimeters have a different set of meter lead connections depending on whether you want to measure amps or volts.

Amps are measured with the meter leads connected in series with the load. Before you make this connection, push the black meter lead into the meters common socket and the red one into the socket that is marked amps (Choose the one marked 10 Amps).  

Voltage measurements are made with the meter connected in parallel with the load. Before you make this connection, push the black meter lead into the meters common socket and the red one into the socket that is marked volts.

The kind of "pinch" tool that you mention is probably an ammeter that is designed to measure AC current. If you try this, use it before your rectifier bridge.

Good luck.

Peter

[GBillerty]

my multimeter fuse was shorted... I will replace it and try back.

THE question is that:  Can I really get 16V at around 100-150 RPM and getting 0.1A

[GBillerty]

meter wired in serie with a lamp "12V bulb 10A max rated"

I just reduced the gap this morning and I got 22V at 150RPM

I will try to post pics or draw of my setup

[GBillerty]

ok!

I connected it to a car battery and then get 22V, 2.2A at RPM. I dont know how to count the RPM. I would think around 150-200 RPM.

This time I felt the cut in torque.

I use a power drill to get it turn.

Will I get more Amps adding laminates to my stator?

Thanks guys!

Here is my setup!

[Flux]

We are getting there slowly.

I still think there is more problem with your measurements than with the alternator.

How do you measure 22v when connected to a battery. Either you are measuring the wrong thing or the battery is sulphated and not holding the volts down.

The battery should hold the volts down to 14v or less for hours at 2.2A. You don't still have that lamp in series do you? if so take it out and try directly into the battery.

I don't know if you have 16 or 18 magnets, you mention both. If 16 you would be better off with 12 coils and make it 3 phase. I am sure you can get your desired 10 A without laminates and a fair bit more with them. You already seem to have a low cut in speed for the output you are expecting so with more coils of fewer turns of thicker wire you ought to get the amps up quite a bit.

Before you change anything sort out your measurements and find out what it is really capable of, then you will have useful data to make changes. If you add laminates at this stage your cut in will be very low and if you are measuring the wrong things you will confuse yourself.

So far 22v 2.2A at 150 rpm is not bad going for a single rotor air gap alternator with only 8 coils.

I assume you are using a single phase full wave bridge rectifier not just a half wave diode.  If so try again directly into a good battery, make sure the dc volts hold down below 14 and the ac volts on the input of the rectifier are similar or lower to prove the bridge is not half open circuit. See what amps you get into the battery with different speeds.

Good luck

Flux

[GBillerty]

OK!

when battery charging, Voltage is regulated to 12V-13V

My cord drill is rated 500 RPM but I doubt my alternator turn 500 RPM with this drill!

I will try to lower the air gap again to get more power.

[Flux]

ok now I follow, 22v open circuit, 2.2 amps into battery. Speed probably drops on load to confuse things.

You are now being limited by the resistance of your coils, that is fairly thin wire.

You will need to use more coils so that you can reduce the turns per coil and use much thicker wire.

Also with no laminates the coils need to be fairly thin as the flux does not penetrate very far   3/8 thick at the most I would guess, any thicker will add resistance with little gain in output.

Reduce the gap between the magnets and coils as much as possible. Increase the number of coils preferably to 12 coils 3 phase. For even more out add laminates and then you can use thicker coils with less turns and even thicker wire.

A lot depends on the speeds you want to run at, you give no idea of your intended propeller.

Flux

[GBillerty]

Thanks Flux!

you've really helped me to understand!

I would take that stator out and try that three phase as my bridge rectifier is made for three phase!

I'll made a new stator. But I will try to get maximuim ouput from that actual stator...

I'll get back soon with more details.

thanks to all again!