parts for an old time genny.

[steamer]

oh and the index arm is held on with one bolt on the side of the orange block. Once in position and tight....DON"T MOVE THE ARM ABOUT THE BOLT!

Just loosen the clamp....and turn the disk.
Put the reticle on the fixed side of the clamp too....not the loose side.

Dave

 

[Kermit]

Hi Kermit,

Here's what I was thinking......

The yellow disk is 7.639" in diameter and is made of plywood......you then take a peel and stick measuring tap from one of the woodworking supply stores and put a 24" long piece all around the OD of the wood index disk

The arm with the tool makers clamp looking thing is just that, and arm with a tool makers clamp on the outboard end. Attached to the side of the clamp and not shown is a little bent piece of plastic with a small colored groove in it. If you index every inch, you will have 24 divisions. Every half inch 48 divisions, every quarter inch, 96 divisions...ect.

Steamer, you have done it again. I initially said I didn't understand you reference to 7.639 inches in diameter.
I've got it now.

You have filled in a missing piece and NOW I know how I'm gonna tackle this one.

You're right about the 1/64th being good enough for my project. Currently, my measurements show I'm in the 1/48 to 1/50 range on the test piece. Even that is close enough that it cannot be seen by the unaided eye. I'm aiming for 1/100th or thereabouts. what I think you guys call 10 thousanths. If I could achieve that I'd be very pleased with myself.

Hi.

I've gone through the posts (drawings and pictures) and have a question. Is it a three phase AC generator (alternator) or a DC one? Since you have a 2 pole field system, which is separated 180º from each other, the rotors coils should have the same amount of poles. The output frequency of a AC generator is directly related to the RPM's and number of poles. In Europe we have 50Hz so on a 4 pole machine, the engine must run at a fixed 1500 rpm (1800rpm for 60Hz), generating 2 frequency cycles at each revolution. Those ancient generators on the initial posts, achieve the same frequency at a much lower speed. The 8 pole one, must run on 750 rpm.

I'm making this a three phase machine by dividing the winding into three groups. Three phases make a much steadier DC voltage when rectified than a single phase AC current will. The AC outputs will be picked up on ring terminals with standard brush equipment. No commutators in this project. Instead I'll be using some big fat triac's with a diode self trigger and add some capacitance for filtering. Presto-instant DC output generator. Going further, I could put in a 7405 or 7412 regulator and further steady my output. Those are good for about 1 amp of current which should be the max this little genny will put out. As long as the genny can keep the voltage above the set regulation voltage the silicon based components will give a steady DC.

Hope that answers your questions,
Kermit

 

[Noitoen]

For a three phase 2 pole machine 2 groups of 2 coils each with 10-12 pitch for the 24 slots you have, the you can connect it in a series/delta way to get three phase.

If you look at some of the small angle grinder's (burnt) armature you will see a 12 slot core that can easily used in a small generator project. I've collected some to attempt the build of a (not so small) brushless model engine. http://www.aerodesign.de/peter/2001/LRK350/index_eng.html

 

[steamer]

HI Kermit,

Ah yes 1/64 at that index plate radius...at the radius of your work piece it will SIGNIFICANTLY smaller. 1/64 is 0.01562. Your work piece is about 2" diameter......The error in your part would be proportionally smaller or
2/7.639 x .01562 or 0.004" inches at the workpiece.

Additionally, you could set up and cross drill a shaft exactly on center in about 5 minutes with the same setup...mount the shaft to be cross drilled in the orange block and clamp it in. Put the drill in the lathe chuck and off you go. If you want the cross drill at an angle, turn the tool post to the angle before you drill.

Dave

...by the way..7.639 is the diameter of a circle with a circumference of 24" inches....

 

[bearcar1]

The very same setup using a degree wheel that is used for dialing in the camshaft timing of car and truck engines would accomplish the same thing without having to resort to any mathematical formulas. They cost very little (unless you get the etched metal versions) and they are quite accurate.

BC1
Jim

 

[Kermit]

For a three phase 2 pole machine 2 groups of 2 coils each with 10-12 pitch for the 24 slots you have, the you can connect it in a series/delta way to get three phase.

If you look at some of the small angle grinder's (burnt) armature you will see a 12 slot core that can easily used in a small generator project. I've collected some to attempt the build of a (not so small) brushless model engine. http://www.aerodesign.de/peter/2001/LRK350/index_eng.html

I think you're describing a distributed wave winding. mine will be simpler, just four windings paralleled and then the next four, then the next four. I've got loads of 30gauge magnet wire, but thats small stuff. Lots of measuring and prewinding work to do. So this plan might change as well. ;D

It's a very plastic build so far, but once its done I'll have something more concrete to commit to paper as far as plans go.


Flying by the seat of my pants and loving it,
Kermit

I'll look further into the wave windings and see if these might prove easier in the

 

[John S]

Ignore me if i don't know what I'm talking about but don't the slots have to be unequal numbers so it can't get stuck / parked ?

John S.

 

[Kermit]

No, no problem. Good question. I don't think it really matters with generators, but motors would be different animals in this respect.

I believe that using an odd number of slots is just one of the criteria for certain type of windings. The two major types are closed coil and open coil windings, and these are broken down further into wave and ring, with various other variations among them as well.

In the genny as I have proposed winding it so far, there are four coils in a 60 degree arc that will be placed electrically in parallel even though the inside and outside coils will differ in voltage by a small amount, this will lower voltage output and increase current output. If I made them groups of different numbers of coils then I could have 4 phases, or 12 phases if each coil was individually connected. Eight phases is also a factor but cannot be done in a balanced way with the winding scheme I'm planning now.


Hope some of that made sense,
Kermit

 

[steamer]

Math involved

Circumference of a circle = PI x diameter of disk......rearranging

Circumference / Pi = diameter of disk

( 24" ) / (3.14159) = 7.639"


Timing disk would work too Bearcar1, but you may have a tough time with fractions of a degree. 24 is even, but 48 and 96 (3.75 deg) are not. Don't know how they are layed out, so I can't really comment

Additionally, Make the disk as large as you can, as it will reduce the error in the part.....Your part would have half the error if the disk was 15.278 in diameter and you indexed every 2 inches for instance.

Better have a big lathe though ;D

If you wanted to make a series of index plates, start with a large disk and turn it down as you go....

This method was taught to me by an old clockmaker....though I can't say I know him personally. I really admire his ingenuity.

Dave

 

[Kermit]

Constrained to stay small by the proximity of the 2000 RPM Chuck...

I have procured an $8, 1ft sq. piece of black garolite, 3/16 thick and a $5 one, 1/16 thick. I will turn a portion of the 3/16 one down to a disc 7.643 inches in dia. and cut it down into two quarter sized pieces with 1 inch offsets. I think I can get two out of it. This will be a simple(not necessarily for me) fit'n'fixture setup and will stay in the vise while machining. I'll use a triangle of 1/8 thick garolite, made from two 1/16 thick pieces glued together. This will give me a clearly visible center line. Insert the angled piece into a previously machined slot so that the long taper tip points outward toward the diameter and align with a paper tape ruler as suggested by Steamer.

plan as viewed from above.

More photos soon,
Kermit

 

[zeeprogrammer]

Read the thread again. This is a really neat project.
I hadn't realized it was that small.
What will you be doing with it?

 

[Kermit]

...What will you be doing with it?

:-\ Uhmmmm, I don't know!

Would make a nice 'load' for a steam engine, no? (Hear that Brian?) ;D

 

[Kermit]

Raw material prep.

3/16 thick Garolite 12" x 12" reduced to 7.75" sq on the table saw. Slight chipping even with two layers of blue masking tape on the 40 tooth combo blade. All will be removed soon.

two 4" x 6" pcs. of 1/16 thick Garolite glued together with a sheet of white paper between. Same tablesaw with two layers of tape. Not as much chipping this time.

Boy, that wore me out! Time for a break.
Kermit

 

[Kermit]

Absolute and total failure. The glue did not hold. Yellow type construction glue. I guess my big mistake was to assume that this material would be in anyway similiar to wood products like hard pressboard and mdf

I have mixed up some old fashioned clear epoxy and prepared the board surface by lightly sanding and degreasing with MEK. (similiar to Acetone)... The epoxy has a 2hr working time, so I'm letting it sit for a few, before I redo my clamping.

I'm feeling like I could have started this all with the words 'dear diary'.

Alright, then. Round two with glue. Making it thicker by using some sticker... (better stop there)

Kermit

 

[steamer]

Garlock is a bearing material, and is loaded with carbon. I hope epoxy works

MDO (f) or plywood would be a better choice, about 3/4" thick.

Dave

 

[Kermit]

The epoxy has held. It is actually an encapsulation/potting compound and is holding very well.

Some glued up raw material being test fit. Nice and gentle press fit into the 1/8 inch slots. I think these will finish up real nice Steamer.

More than I need for this jig, but 1/8 stock with a white center line seems like it might be handy for other projects.

Garolite Grades and Composition

Garolite with PTFE?? Hmmmm... ;D
Kermit

 

[Kermit]

Dear Diary,
The thin paper line is clearly visible after a quick sanding to get the epoxy off the edge. I feel good that 'one' of my plans has worked out as well as it could have. Albeit a small victory, at this point I take any I can get.
Time to tear down my saw set up and put the face plate on the lathe, in prep for turning the base material for my jig. I'm going slow here on purpose, as this gives me time to make plans for how this jig can be used for more than just this one project.

Perhaps that is more Chess than this Checker player can handle, ;D
Kermit

 

[steamer]

Hi Kermit,

Trying to follow along.....what are we building now?

Dave

 

[Kermit]

Still working on "the jig" as sketched in a few frames up.

This is just a piece that will be inserted in a previously cut slot and will extend from there to the outside circumference (the edge) where the tape measure will be located. The white center line will be just that and act as a marker for positioning.

The reason I have four is from cutting them and finding out the first glue did not hold. ;D

 

[Kermit]

More continental drift. After many aeons of time the situation has evolved and parts have revolved.

Metal clamping tools damage the surface of these black garolite parts because it is so brittle. Enter three sewing thread spools. Cored out on the drill press with a 1/2" Forstner bit. All the nuts are covered on the bottom with masking tape as well.

A light rub with 220 grit sandpaper removed the burrs along the edges of the center recess.

Well look at all those circular scratches! Looks like a record album. Makes me want to fire up the record player...Kermit sings his greatest hits. ;D