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windymiller
Junior Member
United Kingdom
113 Posts |
 Posted - 06/08/2008 : 22:51:06
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Hi everyone at gotwind.
Been chewing on this idea for a while...
Im thinking of joining two car alternators together using the same shaft to rotate on.
Ive made some headway by experimenting with one alternator first of all, by rewinding the stator with .8 mm wire 28 turns per phase.
Also replacing the field coil with a large ring magnet.
The results were good in some respects as there is no cogging at all.
The down side is a good rpm is needed to produce above 13 volts (approx 500 rpm).
The amperage is goodish...but i dont want to use thinner guage wire which would increase the voltage...but lower the amperage.
Im going to try and shoehorn two together on a common shaft and see what happens....obviously phasing the two together will be necessary.
Any thoughts why it might not work will be appreciated.
Cheers WM
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gotwind
Forum Admin
United Kingdom
1067 Posts |
Posted - 07/08/2008 : 17:42:17
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Nice,
A couple of images would be good to see WM
Ben. |
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windymiller
Junior Member
United Kingdom
113 Posts |
Posted - 07/08/2008 : 18:08:08
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Hi ben ...ill see what i can do .
Cheers WM. |
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pntrbl
Starting Member
USA
12 Posts |
Posted - 08/08/2008 : 14:56:39
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1st post but I've been lurking along for a bit. Like the OP I've got a project going with 2 Delco-Remy 10si's so it seemed like a good time to join up up and chime in. Maybe my fumbling around will give Windymiller some ideas.
I need to have both 12v and 24v charging in a portable off grid package and mostly because it's what I had laying around, I'm using the aforementioned alternators and a 5.5 Briggs and Stratton motor.
With the phasing issue between the two being a bit too tricky for the likes of me, I've got them setup to run in series. The alt on the bracket side is isolated from ground and will do the high side, 12-24v work, while the rear alt will do the low 12v side.
Obviously it's not finished and tested yet, but I think/hope it'll work!
SP |
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windymiller
Junior Member
United Kingdom
113 Posts |
Posted - 09/08/2008 : 12:49:37
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Hi pntrlb. Welcome to the forum....im really impressed with your idea.
You ll probably find that us windies are always hunting around for new ideas which will not take too much to construct in the way of expense and time.
Im assuming that you still have the field coil inside to create the magnetic field, not a ring magnet?.
Also have you altered the stator in any way....im guessing no.
I think your engine speed will enable the standard alternators to work sufficiently to produce good voltage/ amps
Unfortunately wind turbines find it difficult to produce good voltage with the standard car alternator without modification.
My idea is to costruct a generator with good voltage and amperage at low rpm using two in line..similar to your set up in appearance,but more condensed and shorter...im sure the more electrically minded can chip in with why...and why not ....may be its not been tried this way so they simply dont know...
Anyway keep up the good work and thanks for the picture...i love lateral thinking...its the only way forward sometimes.
Cheers WM
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pintail
Starting Member
United Kingdom
40 Posts |
Posted - 09/08/2008 : 14:20:31
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Hi pntrbl I see that you have a welding lead clamped to the work bench, be careful as welding & alternators do not mix it can destroy the diodes/charging regulator, looks like a nice bit of kitvery impreessed.
Pintail. |
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pntrbl
Starting Member
USA
12 Posts |
Posted - 09/08/2008 : 15:19:56
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You're right WindyM. The alternators are stock GM. With the Briggs I can turn 'em 6 grand so there's no point in modifications. Hardly renewable energy tho!
And Thank You for the heads up on the welder vs diodes Pintail. If they don't work when I get some electricity into the field coils I'll know why.
Got a belt on it and spun the alternators for the 1st time yesterday, which promptly uncovered a design flaw. I drilled and tapped the back of the rotor in the front alt for a screw in stub to pin to the coupler. Shoulda used a LH thread. As soon as it fired the stub unscrewed and the whole rig tried to take itself apart!
No harm, but now we're on hold while I order up a 7/16-20 LH tap.
Which is a perfect excuse to get back to work on my anemometers! LOL! I'm gonna build me some windmills.
SP |
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gotwind
Forum Admin
United Kingdom
1067 Posts |
Posted - 09/08/2008 : 22:31:16
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pntrbl.
Welcome also.
My only thought with your set up is shaft alignment, I suspect you have covered this angle.
Have you some kind of clever coupler between each alternator?, at many 1000's of revs I suspect this may be a concern.
Ben. |
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pntrbl
Starting Member
USA
12 Posts |
Posted - 10/08/2008 : 01:40:58
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Thanx for the welcome and Happy Birthday Ben!
The coupler arrived in a box of stuff along with a milling machine I've been neglecting. Each side of the coupler has 3 fingers and there's a 6 bladed piece of rubber to go between the fingers. It should tolerate some mis-alignment but I was able to hold runout to .006 on the front half with the rear being dead nuts. I'm gonna try to do better when I make a new LH stub for the offending front half.
I did briefly do an arm's length full throttle run before noticing the problem and it seemed nice and smooth. At idle the rear alternator was jumping around some but I'll be blaming the Briggs for that. I initially mounted the Briggs on a small wood bench for testing and had to sit on the bench to keep it from walking all over the shop! It's a bit rough ...
SP |
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Hefhoover
New Member
United Kingdom
86 Posts |
Posted - 10/08/2008 : 23:19:20
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Interesting idea there Windymiller, it'll be interesting to see how you get on with it.
Really neat job there Pntrbl.
The coupling you describe is called a "Spider" type coupling and is a very versatile coupling available in a wide variety of sizes and tolerates all kinds of service conditions.
See link for example :-
http://www.coleparmer.co.uk/catalog/large_image.asp?img=07127AF.jpg
Hef. |
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windymiller
Junior Member
United Kingdom
113 Posts |
Posted - 11/08/2008 : 09:16:50
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pntrbl
can you tell us which direction the out put shaft turns on the Biggs and stratton motor when running ?.
If its counter clockwise then the cooling fans at the front of the Gm units will not work as efficiently....the blade was designed to draw air through the units to aid cooling,so only works good, rotating in one direction.....not criticizing but making you aware of a potential cooling problem under load conditions.
Also id be interested (and appreciate ) to see how you attached the couppling to the rear of the first unit...good luck.
Cheers WM |
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Hefhoover
New Member
United Kingdom
86 Posts |
Posted - 11/08/2008 : 21:57:07
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Just another question,why did you decide to isolate the alt nearest the bracket, especially as the coupling also isolates.
Keep up the good work!
Hef |
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pntrbl
Starting Member
USA
12 Posts |
Posted - 12/08/2008 : 04:24:16
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The Briggs turns CW when looking at the shaft as will the alternator's Windy and Hef called the coupler right on. I didn't know it was called a spider until he said it but yeah, the link Hef posted is same type.
It's apart for a spot o' design change so I snapped a pic.
The rear alt is on the left. Had some shaft to work with on that so the coupler is pinned on. The rubber isolator and the self-disassembling half of the coupler are in the middle. The front alt is on the right and you can see where I popped a hole in the back of the bearing so I could access the tapped hole I put in the rear of the rotor shaft.
It's obvious to me now the weight/drag of the rear alt is gonna unscrew a RH thread every time. That didn't have a chance of a snowball in you know where of working .......
SP |
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pntrbl
Starting Member
USA
12 Posts |
Posted - 12/08/2008 : 04:44:48
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Hef, the front alt case is isolated from ground because the plan is to charge the high side (12-24)of a 24v battery bank with that one. This contraption is supposed to power a portable security trailer that has both 12 and 24v requirements. A DVR is the primary 24v user but we'll need 12v for various camera's, a sat link, the control board, and probably numerous other bells and whistles. I'll have to do my best to balance the loads so each battery discharges at similar rates, but with all the various pieces there should be lots of options.
The coupler grounding the front case was the actual failure mode. Once the front half backed off and met the back one it wasn't gonna go anywhere else. I probably could have kept the alt's spinning at 6 grand as long as there was gas in the Briggs.
SP
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windymiller
Junior Member
United Kingdom
113 Posts |
Posted - 12/08/2008 : 10:27:38
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Hi pntrbl.
Thanks for the info,and pictures....
coincidentially i had a customer with a wood chipping machine with the same coupling design to transfer power from the diesel engine to the hydraulic pump .(the couplings were key wayed and prevented from sliding off by incorporating grub screws tightening coupling ends to the shafts.)
The rubber in the middle acts as a cush drive between the two claws.
clearly this kind of transmission coupling can tolorate quite alot of abuse,as these chipping machines really get some "hammer".
Ive also tried to understand why you claim the coupling unscrews its self.
If the engine rotates in cw direction...then the alternators turn cw also.
If the tapped hole in the rear of the first alternator is tapped RH thread,and the coupling is pinned to the second alternator shaft,then in my mind it should only succeed in tightening it self more not un doing its self.
If rear alternator is under load then ...again it should only succeed in screwing the coupling tighter...it could be that theres another reason for it coming loose.
Loctite on the threads can help to a point, but i think a more permanent method should be adopted for reliability IE a steel roll pin...or keyed shafts .
Hope ive helped in someway...may be ive failed to understand it properly and got it all wrong.
Any way good luck.
Cheers WM. |
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pntrbl
Starting Member
USA
12 Posts |
Posted - 12/08/2008 : 12:38:12
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Jeez Windy, now I'm confused, which incidentally, happens all the time. I just went out there and grabbed the coupler with my hand to simulate the drag of the rear alternator and yeah, it screws right in, not out!
I have to get off to work at the moment but you'd better believe I'll be firing that rig up again as soon as I get home .....
And Thanx.
SP |
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Topic |
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Delco remy experiment.
