Author Topic: 3 single phase rectifiers in series (Read 8319 times)

Turfdr · « **on:** February 12, 2009, 02:38:12 PM »

I just finished converting a Delco 10dn alternator to a pma.

On a lathe it puts out 3 volts oc 5 amps sc @120 rpm , 7.3 volts 16.4 amps @320 rpm and 14.3 volts @620 rpm (can't check amps as meter is limited to 20 amps).

I'm guessing it should put out 12-12.5 volts at about 500 rpms.

I'm using the original stator and the housing is stamped 55a but the seller claimed they are rebuilt to 65a.

I pulled the rectifier out and want to run ac to the battery and rectify it there.

My question is , can I use three bridge rectifiers in series to triple voltage until rpms reach

500 then with a micro chip monitor rpms and switch to the original rectifier with relays to get the best of both worlds? I know the amperage will be reduced , but at least it will be charging in lighter winds.

I did this with a 34 2-phase bipolar stepping motor but it had 2 wires per phase and the pma has 3 wires to the rectifier and 3 connected together.

Also, I bought several of these alternators that were advertised as 65a but they have

different wire sizes and # of turns.

This one has about 11 turns and wire size of .055".

Can anyone tell me what the stator would roughly be rated.

Any help would be greatly appreciated!

Thanks.

bj · « **Reply #1 on:** February 12, 2009, 11:51:23 AM »

Turfdr--can only comment on the wiring of these alts. Have been messing

with them for about 3 years now, as PMs. They were available, in the same

basic case, from 37A to 65A. Different windings on the stator, and in the

rotor. Parts are all interchangeable. The trouble is, rebuilders don't

necessarily get the original parts back in the same case. Generally, though not always, the lower Amp stators have more winding turns, but smaller wire. Lower rpm for cut in. If memory serves me, they go from 11 turns/coil down to 9.

Wire size from 14 to 18. Two different winding patterns as well. So far,

I have seen six different rotors, but as a PM, doesn't matter.

Hope this is of some help

bj

Turfdr · « **Reply #2 on:** February 12, 2009, 02:11:26 PM »

Thanks bj,

It looks like it's a 37a stator then.

Maybe you can tell me how to remove the capacitor for the casing?

ghurd · « **Reply #3 on:** February 12, 2009, 02:37:48 PM »

You could series the bridges, but it would not be a very good idea. And the giant caps to make it even a tiny bit useful would not be cheap.

Wire it star. Looks like it will reach 12V cut-in at around 335RPM.

Do not try to get the cut-in lower than that, or it may cause problems getting the blades figured out.

G-

tecker · « **Reply #4 on:** February 12, 2009, 02:43:10 PM »

That's a 60 amp alternator you can count on 18 to 20 amps per phase although you'd need a good sized blade set to push it that high ( ablade set for 60 amps will probably be too big for the shaft and would need a bearing for the blade set).But in a stiff wind it may get there I 've worked over a mess of these jewells . Rewound and used them as is here's apick of the a 10 dn ready for 3 phase wye down the pole .I bring the Star out also and some I also have seperated for star delta. Pictured is the diode removed and insulators made from 5/16 pecs pipe drilled out with a 3/8 bit and 1/4 pecs inserted and a 1/4 20 stud this one I used some stainless studs .I'm replacing now because they have a tendency to loosen (using Brass ) the three connections go down and you can use the diode combos but the voltage rating is low and they like to pop when a pwm pulse exceeds the piv here's a pic I post a finished unit adapted to baike forks as Yaw I like a cover made from a 4" cap and 6" sleeves around the bussiness end .I post it this weekend .

My favorite star circuit

Janne · « **Reply #5 on:** February 12, 2009, 02:58:43 PM »

Hi Tecker. Could you explain a little more what are the 2 caps doing in your diagram?

tecker · « **Reply #6 on:** February 12, 2009, 03:06:28 PM »

The two caps jacks the voltage up at the star point because the charge lingers with the rotation it jacks up faster if the batts aren't way dead .

bj · « **Reply #7 on:** February 12, 2009, 03:07:53 PM »

Turfdr--it pushes out, sometimes a bit stiff. Support the case with a

deep socket/ piece of pipe etc and push it inward. I have bent or broken

cases when I didn't support it on the inside. I you don't care about the

cap, a hammer and punch works, again-support.

tecker · « **Reply #8 on:** February 12, 2009, 03:11:31 PM »

Here's the one I 'm working on now the cover sleeves are cut and I'll cope them out tho fit and and cut and grind the sleve to fit cleaner epoxy and paint .It an't the ritz but it looks ok

Todd a · « **Reply #9 on:** February 12, 2009, 05:05:44 PM »

You really like big pictures. Well it looks basically like a standard 3 phase diagram, but using standard diodes instead of a bridge rectifier. It also looks like they have a capacitor in there to help smooth out the signal a bit.

kurt · « **Reply #10 on:** February 12, 2009, 05:57:02 PM »

Turfdr, 3072px × 2304px and 3144.52 KB pictures are just unacceptable here. we have image posting rules. no larger than 640 x 480 and less than 150KB. therefore i had no choice but to remove your comment with the offending image in it. feel free to repost with a properly sized picture.

thank you

Kurt (editor)

Turfdr · « **Reply #11 on:** February 12, 2009, 06:19:32 PM »

Sorry Kurt I'm new to this and I just point and shoot , don't know how to set camera. I'll work on it.

Turfdr · « **Reply #12 on:** February 12, 2009, 06:21:12 PM »

Thanks bj for the tip on supporting case!

Tecker, is that 4th wire were windings connect together and what are the capacitor values ?

I got a lot of 36 of these slightly blemished blades on E-bay for like $4 each.

3 blades worked well with the stepping motor but it only put out 12a max.

I'm hoping 6 of these (5') will spin this pma to charge 36v forklift battery split into one 12v and one 24v.

I plan on building several of these if this one works out (first time wind project).

Hopefully bearings won't be an problem , but they're cheap to replace.

kurt · « **Reply #13 on:** February 12, 2009, 06:48:34 PM »

you need to use some photo editing software and resize your pictures before posting them usualy your digital camera comes with some kind of photo editing software but most times it is overly complex junk your best bet would be to get one of the many free photo editing programs avalable on the net some good ones for windows are Faststone image viewer (this is the one i use), Irfenview (this has been recomended here quite a bit), paint.net, gimp for windows(complex but very powerful) they are all free take your pick.

tecker · « **Reply #14 on:** February 12, 2009, 11:57:15 PM »

I think I know the blades your talking about .The carbon fiber blades . I have to say the diameter is about right but your probably going to have to get it up in the good air to get the torque from these blades . Rpm wise they are high speed blades.

tecker · « **Reply #15 on:** February 13, 2009, 12:04:06 AM »

Yes I saw the photo from your files . Plan on finding a place where the noise won't be a problem and where you can get the head up in a solid wind .

tecker · « **Reply #16 on:** February 13, 2009, 12:17:06 AM »

Yes three phase the caps force the star node to rise in voltage you don't get current through the star point but as the rotor rpm increases the charging phase rises a little faster and retains some energy as the rotor speeds up and slows down .

wooferhound · « **Reply #17 on:** February 13, 2009, 04:39:14 AM »

You can also set your camera to VGA resolution. The pictures will come out correctly sized without using photo software to do it. But remember to set the camera back to high resolution for the family pics.

tecker · « **Reply #18 on:** February 13, 2009, 06:42:43 AM »

The caps should be in excess of 5k uf at 50 volts charge the caps up and see if they hold charge of 20 volts for a good while .

Turfdr · « **Reply #19 on:** February 13, 2009, 07:18:25 AM »

Thanks wooferhound, figured it out.

The back yard overlooks a large valley to the south and west and it seems to accelerate

the wind. So we get some good winds most of the time and the nearest house is about 600' so I don't think noise will be a problem, for the neighbors at least.

tecker · « **Reply #20 on:** February 13, 2009, 08:53:22 AM »

Let us know if that hub flies well with the delco

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Author Topic: 3 single phase rectifiers in series (Read 8319 times)