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Project Journals => User Journals => Bryan => Topic started by: Bryan1 on January 12, 2012, 04:45:50 am

Title: Mini Dual Axial Project
Post by: Bryan1 on January 12, 2012, 04:45:50 am
G'day Guy's,
                    With the left over neo mag's off my 4kw motor conversion project (soon to come) I decided to have a go at making a mini dual axial genny. As I had enough magnets + one spare I decided on doing a 16/12 config.

This is the cad image of the coil/magnet setup

[attachimg=1]

Next is a pic of one of the mag rotors just cast

[attachimg=2]

A pic of the front mag rotor all machined up to true it and painted

[attachimg=3]

Here is the mount I made for it

[attachimg=4]

All setup ready for the one coil test

[attachimg=5]

My crude but effective test setup, I used some plastic tube and used somw magnet wire to connect it then powered it off my 50 volt DC motor using my 30 volt lab psu.

[attachimg=6]

here is the result from the test coil setup

[attachimg=7]

This weekend I'll get the stator all wired up and the stator mold sealed with my free motor winding varnish (which is a great MDF sealer) and grab a new bottle of catalst for that 4kg's of fiberglass resin I have here so I can get the stator done.

I do have my eye on a 170x50mm x3.3metre straight grain Oregon plank at work and tomorrow I'll ask the boss as it's not going to be used if I can have it for my blade set for this project.

More to come.....

Regards Bryan

 

Title: Re: Mini Dual Axial Project
Post by: ChrisOlson on January 13, 2012, 01:15:22 pm
Hi Bryan,

Looks to me like you'll get 12 volts DC out of it at just a little less than 200 rpm (assuming you wire the stator in wye).

Are those little magnets about the diameter of a nickel?
--
Chris
Title: Re: Mini Dual Axial Project
Post by: oztules on January 13, 2012, 03:42:23 pm
I'm not sure your resistance figures are correct......     0.11R for the coil, and 0.16 for the leadin.... 45 turnsof wire for 0.11r and a few inches of wire for 0.16.... are you sure about this?

If 24v then around 370-390 rpm cutin. What blade size are you considering.... 2meters?



..................oztules
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 13, 2012, 04:49:34 pm
G'day Oztules,
                       When I short the leads of my fluke 865 scope meter the reading isn't zero it is 0.16 ohms so to correct the ohm reading I have to subtract that figure from the result. Today's jobbie is connecting the coils on the stator and hopefully get it cast. next weekend is a trip to the salvage yard to find some hardwood for the blades and Yes I am going for a 2 metre blade set for this project. Also our house array is 24 volts so yes the cutin will be around 380 rpm.

Cheers Bryan

Inspired to get going again after a night of sparkling ale......
Title: Re: Mini Dual Axial Project
Post by: ChrisOlson on January 13, 2012, 05:10:18 pm
Bryan, what is the size of those magnets and what air gap you using?  It would be interesting for me to try to figure backwards to see if I can figure the flux density in the air gap with those.
--
Chris
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 13, 2012, 08:54:46 pm
Hi Chris,
             The magnets are 16x13mm diameter and N50 grade. Off memory with the single coil test the air gap was 16mm. Anyway I got 2 phases wired up on the stator this morning but I had to go take the sons car back to the mechanic and by the time I got home the yard arm was waiting for me. Anyway with my elcheapo DMM each phase measured 0.8 ohms. Once I get all the wiring done I use my fluke 865 to accurately measure each phase. In the morning I'll get the stator finished and have it all ready for casting so I'll take a few pic's.

         I will see how the high cutin goes and I might endup making a new stator using thinner wire so I can get the cutin for 24 volts down.

Regards Bryan
Title: Re: Mini Dual Axial Project
Post by: Norm on January 14, 2012, 08:24:40 am
Nice Byran,
     Showed the wife....see other people have clutter around their workbench too!
and she says.....'but that's not in the kitchen ! '
to me I'm impressed with the results.
Like your shop....I'll trade you any day !
BTW I'm not that into FaceBook but wife tells me yours just
has to look for Barb Fritzsche and ask to get on her facebook
and she will yes it okay?
Norm (& Barb) :)
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 14, 2012, 07:17:12 pm
G'day Guy's,
                    Anyway got the stator all hooked up and took a few pic's so here goes...

This one is for Oztules showing the shorted leads



(http://www.anotherpower.com/albums/album129/shorted_leads.gif)

The Ohm reading from the U phase

(http://www.anotherpower.com/albums/album129/U_phase.gif)

The Ohm reading from the V Phase

(http://www.anotherpower.com/albums/album129/V_phase.gif)


The Ohm reading from the W Phase

(http://www.anotherpower.com/albums/album129/W_phase.gif)

I silver soldered the joints together then used self amalgamating tape to seal them

(http://www.anotherpower.com/albums/album129/solder_joint.gif)

A pic of the Stator

(http://www.anotherpower.com/albums/album129/stator.gif)


Now as the shorted leas read 0.15 ohms this has to be taken off the Ohm reading so the average is say 0.70 Ohms less the 0.15 ohms which will make it 0.55 Ohms on average.

It does seem everyone goes with a star config so I reckon thats the way I'll go too.

Anyway got a brew of Ginger Beer to bottle then I can get on and get the connections finished and get the mold finished.

Cheers Bryan
Title: Re: Mini Dual Axial Project
Post by: oztules on January 14, 2012, 09:22:25 pm
 Thanks Bryan.
It's a shame the DVM's dont have a zero function to calibrate the R scale..... not even the expensive ones apparently.

Good low R in the stator. Should control your blades pretty well.


.............oztules
Title: Re: Mini Dual Axial Project
Post by: rossw on January 14, 2012, 10:03:24 pm
It's a shame the DVM's dont have a zero function to calibrate the R scale..... not even the expensive ones apparently.

I have a "reasonable" one - Uni-T UT71E (cost me about $150).

5 digits, reads ohms to 2 decimal places - but *DOES* have a "relative" mode, which works perfectly as a lead "Zero".

If anyone has a meter with a relative mode, it works nicely as a pseudo-zero.
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 21, 2012, 06:48:53 pm
G'day Guy's,
                    Nice sunny day here so got the stator wiring all finished and the mold done. Just need to wait for the ISONEL 642 varnish to dry then I'll be ready to grease everything up and get the stator finally cast.

The Mold

(http://www.anotherpower.com/albums/album129/mold.gif)

The Finished Stator

(http://www.anotherpower.com/albums/album129/stator_001.gif)

The ISONEL 642 I used to seal the MDF mold to make it waterpoof

(http://www.anotherpower.com/albums/album129/isonel.gif)

Anyway hopefully in the hot sun that varnish will go off rock hard and I can get the stator cast this afternoon.

Cheers Bryan
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 25, 2012, 07:35:54 pm
G'day Guy's,
                    Well sanded back the mold this morning and greased it all up then decided to go for it and cast the mold. I mixed up approx 900ml of fiberglass then added some Q-cell in and got the amount just right with the only wastage coming from when I put the lid on and sealed it up. Not too hot today so got the mold out in the sun so it can cure and hopefully this weekend it can come out of the mold.

[attachimg=1]


                   Now for the question as it is full summer here and the average temp will be around 30C in the shed would saturday be the right time(thats 2 days) to pull the mold apart ot should I wait longer.??????

Cheers Bryan ( Hiding the last of the homebrew ginger beer from the missus as she near polished off the lot)
Title: Re: Mini Dual Axial Project
Post by: oztules on January 25, 2012, 11:59:13 pm
"or should I wait longer"
Due to an energetic mutt that bumped me while I was pouring in the hardener/catalyst.... mine took about 8 minutes... complete with smoke coming out the sides and all the attendant excitement. It was stuffed to the gills with glass matting, and that saved it. It has been flying for about 4 years now.... so depends how you mixed in the ratios and temperature.

Here is the instant stator :
[attachimg=1]

And the critter that caused the high speed curing..
[attachimg=2]

In other words.... err.... how long is a piece of string????



...............oztules
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 27, 2012, 04:47:07 pm
G'day Guy's,
                    Well first quiet friday night in ages so got on early this morning to get the mold out of the stator. After taking all the clamps off and the top not coming off I knew I was in for some fun. I had to basically cut the lid of in small bits and found out the top had completly stuck to the top of the stator. When I got the top completely off a few taps got the mold moving but the centre came out with it. Anyway not be to be put off I went and got my head knife and proceeded to skive off all the mdf. So although the mold did pass the water test and it was fully sealed all I can say if one does want to a mold out of MDF you have been warned....

The mold and result

(http://www.anotherpower.com/albums/album129/mdf_mold_after.gif)

The Head Knife used to skive the MDF off

(http://www.anotherpower.com/albums/album129/head_knife.gif)

The Top of the stator

(http://www.anotherpower.com/albums/album129/top_of_stator.gif)

The Bottom of the Stator

(http://www.anotherpower.com/albums/album129/bottom_of_stator.gif)

I did see a few wires were exposed on the top of the stator so first job is paint some of that varnish on to totally seal the stator then I'll do a top coat.

Now as the stator is only fiberglass with some cloth on both sides I do feel if I need to short the winding in wild weather it could break the stator so I'll make up some perspex and glue them on both sides to give the stator outer a bit more strength.

Got a few house jobbies to do then I'll get back to it and hopefully tomorrow I can get the lathe test done setup and done.

Cheers Bryan
Title: Re: Mini Dual Axial Project
Post by: oztules on January 27, 2012, 08:33:50 pm
I was trying to find a mold amongst the bit of wood..... but I couldn't.

I was worried mine would do that, so placed a garbage bag in the mold.... so I knew it would come out. (mine was chipboard)
It works but gives a textured look to the stator... makes no difference, just looks poor.... but at least it won't stick.

That aside, the stator looks pretty sturdy, the perspex won't lend it any real support, you may be better to just add another layer of glass over the top each side. This will seal your wounded wires, and add real strength to the stator.

Mine is supported in 9 places with 1/2 inch bolts. I regularly short break it (all the time actually) from power as high as 5kw.... with no ill effects.

(My Electric Vehicle charges from the mill. Plug it in, the mill starts, when the car is full, it just turns the mill off..... it does not wait for a lull in the wind)

It's coming together nicely by the looks.


...............oztules
Title: Re: Mini Dual Axial Project
Post by: rossw on January 27, 2012, 08:38:43 pm
I was worried mine would do that, so placed a garbage bag in the mold.... so I knew it would come out. (mine was chipboard)
It works but gives a textured look to the stator... makes no difference, just looks poor.... but at least it won't stick.

The odd occasion I've had the same concerns, I've used kitchen cling-wrap. It isn't perfect, but you can smooth it down real well before you start and don't get so many horrible plastic folds cutting into the epoxy.
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on January 27, 2012, 09:06:37 pm
G'day Oz,
                I'll going with 4 off M16 grade 8 all thread for my stator mounts and I painted the stator with that varnish this morning so it is all sealed now. Once I drill the mounting holes I'll put a top coat of 2 part epoxy paint on to fully seal it. Anyway the stator is 14mm thick so I'll be going for a 16mm(5/8") airgap. Tomorrow I'll drill out some spacers and machine up a boss plate for the blade hub so everything can sit square then it will be ready for the lathe test. I am hoping my big lathe in back gear will have enough grunt to give this a real good testing as I really can't wait to see what this baby will put out.

           I am tempted now to pull down my 2hp motor conversion so I can use the lattice tower with both sections for this mini mill as the 3 metre blades are showing some damage from a few years running and I do want to give that 2hp motor a rewind with thicker wire so I can turn it from a baby into a real grunter of a mill.

        The missus is already saying if this new genny is closer than the shed how am I going to sleep at night and I said just listen to the batteries charging as it will be quieter than running the genset. She has said my 2hp does make a bit of noise and I replied yea only in a gale when it's doing over 600 rpm and the 20 amp gauge is topped out. 

     More to come tomorrow....

Cheers Bryan.
Title: Re: Mini Dual Axial Project
Post by: Wolvenar on January 28, 2012, 05:48:26 am
I have used freezer paper before. I know that there is question about if the wax will weaken things but I haven't had anything significantly weakened to the point I could determine it.
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on February 04, 2012, 12:03:03 am
G'day Guy's,
                  Well back to the drawing board with the stator, did a lathe test today and at 600 rpm got a pultry 2 amps out of it. Anyway it would make for a good 12 volt stator as @ 240 rpm open circuit volts are about 15 volts. O'well the learning curve continues and this time i'll make the new mold out of marine ply and paint it with epoxy paint.

Cheers Bryan
Title: Re: Mini Dual Axial Project
Post by: oztules on February 04, 2012, 04:11:56 am
Thats sad news, i would have expected about 10A into a 26v bank with your 1.1R stator

Into a 30v bank, it would be back to 6Amps (@600 rpm).... cant work out how you only got 2A.....


.............baffled

.....oztules
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on February 04, 2012, 07:28:54 pm
G'day Guy's,
                   Well had another go today and I used the fluke DMM on 10 amp range. I also setup the VFD to show amps out. I found open circuit voltage for 25 volts is just over 400 rpm.

                   Anyway I set the jog hertz and used the jog rather than run and had it top out @ 500 rpm and saw 4.6 amps out of the fluke. Now the vfd was pulling at first around 3.3 amps then as soon as it cutin it jumped to 8.9 amps, the current was slowly rising next thing the VFD went in error mode for over amps. In order to check RPM I made a bung to got in the back of the lathe spindle and used my old Smiths RPM gauge.

                 So it does look like my old 2hp lathe didn't have enough guts to give this a real test so I might go ahead and give it a go. I got 3 off planks of nice straight grain well seasoned pine on friday so I'll make a set of 2 metre blades and see how many amps I can get out of this stator in real world conditions. If it aint enough then I'll make a new stator for it.

Cheers Bryan



             
Title: Re: Mini Dual Axial Project
Post by: oztules on February 04, 2012, 08:24:23 pm
2m blades and a boost converter or Gordons Cap doubler may be the ticket for that stator. Cut in will be a little late for normal sites, (no worries here), hence the doubler circuit. (tsr7 or more)

How many cans per blade do you reckon.... :D


................oztules
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on February 04, 2012, 08:32:36 pm
2m blades and a boost converter or Gordons Cap doubler may be the ticket for that stator. Cut in will be a little late for normal sites, (no worries here), hence the doubler circuit. (tsr7 or more)

How many cans per blade do you reckon.... :D


................oztules


G'day Oz,
              Yea I was looking last night about the cap doubler and might have to knock one up but as far as cans per blade I am tempted to do the chainsaw method so it will be dry day until there finished so I'd say NO pale ales while cutting then a slab afterwards  ;D ;D ;D

Cheers Bryan
Title: Re: Mini Dual Axial Project
Post by: jlt on February 04, 2012, 09:52:36 pm
 I have used pressed wood before and mine came out okay.
   
 I used candle wax on mine and burned it into the wood with a propane torch.
Then smoothed the wax with a hot iron.

It didn't stick at  all. Fell out when I turned the mold over.
Title: Re: Mini Dual Axial Project
Post by: RichHagen on February 05, 2012, 03:44:35 am
I have used a thick coating of axle grease, but I would not do that if you add a lot of catalyst or cast it where it when it is very hot out.  Only stuck a couple of minor places.  I also used some wax, actually from an old plumbing sealing ring, and that worked pretty well also.  I put it on so thick, and did not smooth it out too well, so it did leave a bit of texture, but otherwise it was functional.  Just some ideas.  Rich
Title: Re: Mini Dual Axial Project
Post by: Bryan1 on February 10, 2012, 10:11:22 pm
G'day Guy's,
                  Well spent a bit of time making up the voltage doubler and did the test with it. Open circuit the doubler soon got to 36 volts @ 300 rpm but connected no current at all @300rpm. Tried again at 350 rpm and got a pultry 0.6 amps so upped the speed to 440 rpm and was seeing 1.2 amps on the fluke and 0.58 amps on the doubler. Anyway look like this stator will be a beer coaster and time to start winding another test coil. This time I'll try 70 turns and use the wire I got out of a seeley motor. With a bit of luck I'll be able to get 2 in hand too.

Cheers Bryan ( downing the sorrows into a doz or so Boags premuim ales)