48volt gen part 2

[PRedATor]

Air gap of about 18mm between mags.

With both mag rotors on I get a reading of around 15 volts turning at 160rpm (2 turns a sec by hand)

I tested a few other leads at random and they vary from 5 - 25 volts, I suppose its where they are on the stator which I don't know which one goes with which wire and I'm getting some cancellation between some and can't explain the high ones.

Oh yeah silly me my camera date is out - Sorry Paul

Regards

Rich

[richhagen]

At least you will know where you'll be on November 4th.  I do not have it clear, are you measuring voltage from individual coils?  Rich Hagen

[PRedATor]

measuring two coils from two wires from the stator, as all the start wires of the coils are connected together as per Hugh's book.

rich

[Flux]

Odd.

Volts between any pair of wires should be the same. Is there any noticeable drag when you turn it. If not it is not shorted turns. Seems likely that you have some coils reversed. It looks as though the star point is buried inside. At least to prove the point with care you should be able to do a bit of brain surgery and get a meter prod on to the star point.

If you measure each coil individually the volts should all be the same. If it is reversed connections you will have to do some skilled brain surgery at the star point, it should be possible to patch it up as a trial stator.

I am not sure what speed you measured the volts at ( 160 rpm is not 2 revs per sec, did you mean 120) I would have expected 25v to be nearer the right value.

Flux

[PRedATor]

Yes Flux I meant 120rpm (silly me)

The coils are all the same way as I checked, double and triple checked that before I encased it in resin.  All the coils had been weighed and counted with all exactly the same measurements.  

I will go an check each pair again with the meter and see what the readings are, I could have been excited and not really concentrating on rpm's.

I hope the exit wires going under the coils haven't been squashed into the turns of coils and shorting the coil making it have less turns.

going to the shed now...

cheers

rich

[hiker]

just a idea--drill a hole down to your starts-then put a screw in their--hook a batt or batt charger to the screw--other lead going to what ever coil you want to test--then hold a magnet in your hand --and see what you get from each coil..should be able to find out the good coils from bad or miss wired coils.............................later.

[PRedATor]

OK so here is the results I have.

Doing 120rpm as best I can, the figues are average volts as its going up and down + - 1.5 - 2 volts.

I numbered each wire from 1 - 10 (this is not representing where they are on the stator as I have no idea of wire to coil)

There is no cogging while turning the rotor.

wire pair           volt reading

1. - 2                   20
   
1. - 6                   20
   
1. - 10                  20
   
2. - 7                   20
   
2. - 9                   20
   
3. - 7                   20
   
3. - 9                   20
   
4. - 6                   20
   
7. - 8                   20
   
9. -10                   20
   
1. - 9                   15
   
2. - 3                   15
   
2. - 8                   15
   
3. - 4                   15
   
4. - 7                   15
   
4. - 8                   15
   
4. - 9                   15
   
5. - 7                   15
   
5. - 10                  15
   
3. - 8                   4
   
5. - 6                   2
   
2. -10                   2
   
   

So there you have it.  I can't do every combination as there are too many but I can select just a pair that get 20 volts and have my 5 phases.

Depending on which pair are connected is the mystery to my results.

I am putting it down to my coils spacing in the stator not being in phase with the magnet spacing on the rotors.

Don't you just love amateurs

rich

[Flux]

I hope the mathematicians can analyse this one but the conclusion I have come to is this:-

Assuming 1 as a reference, 2 is reversed, 5 is reversed and either 3 or 8 is reversed but I can't decide which.

If you are certain you have all the starts together you must have turned 3 coils over or wound them in the other direction.

Flux

[Gary D]

Not sure if this helps, but since you're building to his spec's, page 39 in Hugh's book has 10 wires out- 2 for each set. No star connection, and 5 rectifiers. Page 38 has trouble shooting advice... Gary D.

[Trivo]

Connect the 5 rectifiers and check the voltage on each it should be ok

on mine i marked the wires in pairs that lined up with the mags for testing and if you select odd numbers the readings vary a lot remember it is not wired 3 phase like most of the other ones done here

Trivo

[PRedATor]

Yes I think I will get it connected to the rectifiers before I start thinking about surgery and get some results, my multimeter broke last night from all the testing.  Have to get a new probe.

Each Rectifier shall have a 20v pair.

I really don't want to have to construct another stator.

rich

[Flux]

Yes try it, it will still give good results with 3 coils doing nothing. You will not get its full potential and it will vibrate more than it would have done when right.

Connect your rectifiers, short circuit the output and see what it feels like when you turn it. It should be very stiff and smooth, if you can feel slight pulsation it should be ok. If by bad luck you have 2 of the reversed coils on the same phase it may pulsate badly but even so it ought to be much better than single phase.

The reversed coils will not heat up or cause harm but will reduce your output.

Good luck

Flux

[PRedATor]

The 5 pairs of wires going to each rectifier for the 5 phases at 120 rpm were:

1. - 2
   
3. - 6
   
4. - 5
   
7. - 8
   
9. - 10
   
   

These pairs all had 20 volts for some reason.

I then soldered up the rectifiers and shorted it, the turns feel stiff all the way around when turning with no pulsing and its very smooth.

I then tested the volts and amps with my meter, was I supposed to put a load on it?

anyway I tried as best I could turning it at 3 turns a second so as to give me a 180 rpm or close to.

The volts were a little above 60 V.

and the amps where around 2 amps or just below.

Is this what I should be getting as I don't know if its good, OK or bad?

Cheers

rich

[Flux]

Volts seem much as I would have expected from your magnets and turns, in fact the dc volts make more sense than your 20v ac figures so it seems as though the coils are working correctly.

I don't know how you measured the 2A. Current readings are only meaningful into a battery, I wouldn't bother with any other sort of load, it will only cause confusion.

If you can connect it to a battery and measure current you can try connecting the other leads and see if the current increases for the same speed, you will not be able to turn it much above cut in speed so you had best choose a speed just above cut in. It may be as well to ignore any leads that don't increase the output, but I doubt that they will hurt anyway.

Flux

[PRedATor]

The 60 volts "is" from the 5 phases in total not from 1 rectifier. I didn't test only one.  I'll have to check out what the reading is from 1.

The 2 amps was just what the meter showed when connected to all the wires from - and all wires from +

rich

[Flux]

Good, the voltage should be measured as you have done, the reading from one rectifier is rather meaningless.

The current measured into a short circuit is really a measure of your strength and not much else, it should rise so quickly that you just can't turn it fast enough to produce much. seems like things are working out fairly well at present.

Flux

[PRedATor]

Thanks Flux I was getting quite anxous thinking I'd have to build another stator.

I will be able to get a better sleep than I did last night now.

Regards

Rich