K55 ceiling fan motor

[rustkolector]

Ghurd,
I agree. The mentioned bulbs were just to see what the voltage droop would be at various loads. The droop was lower than I expected, so I think the generator is stout enough to handle well in excess of 100 watts. Unfortunately, I suspect the efficiency is quite low and my little 4 cylinder engine will be hard pressed to produce the needed torque for more than about 40-50 watts of power. I will likely be running it in the 81-96v speed range. The AC load would be an array of very small bulbs on one phase with a rheostat or dimmer switch to be able to vary the lighting wattage. The other phase (or maybe one coil) will be tranformed and rectified to handle the 6 watts of 12vdc loads.

Now to design and builld the generator frame and bearing support. Thanks again for your help.

Jeff

[rustkolector]

It has been awhile, and this project is fiinally nearing completion. I have a few more remaining newbie questions. I have isolated each of the generator's 4 coils.  I am getting 115vac on each coil at the desired 700 RPM. These coils were originally wired two in series in each phase winding with two phases. My first question is, can I parallel two or maybe three of these coils for the AC output for lighting, and then use the remaining coil (s) for a rectified 14v DC output circuit.

My second question is should one leg of the AC output be frame grounded? And also, how should the AC to DC rectifier side be grounded? This is a demonstration model and safety is important.

As always, thanks for any assistance.

Jeff

[ghurd]

Maybe?
You can only parallel 2 coils. They have to be in phase, which is a pair that were in series. 
It may not be possible because of the winding and how the magnets were installed.
Feel how easy it spins when the coils are not connected.  If it gets any harder with the coils connected, you either have the wrong coils (probably feels like heavy drag), one is reversed (turns very stiff), or the magnets are making them a bit stiff they may be out of phase.

I think I would use them separately anyway.  Less issues with circulating currents.

Might be worth while to feed that 115VAC to a 12V transformer, then rectify to DC.
Direct rectification will result in a high DC voltage, and that's considered not good.

I do not think 'grounding' anything is a good idea in this situation.  If there is a good way to do it, I can't think of it right now.
If there is a good reason to do it, I can't think of it either.
Maybe someone else will chine in.
G-

[rustkolector]

Ghurd,
Thanks. I suspected only the phase coils can be paralleled. I prefer to have only one AC circuit and one DC circuit so I will try the two paralleled circuits first. I will try the individual coil circuits if the paralleled coils don't work out. Using the 4 individual circuits is a lot more wiring. I like the transformer idea, but I have to include a PWM regulator since the AC output voltage may vary as much as 15-20% depending on how the speed is set and how much load is applied. A unit this small has no governor.

I will skip the grounding for now, since I will rarely have an earth ground available.

Jeff

[ghurd]

Not sure what the DC power is intended for, but most "12V" devices can operate properly from about 10.5V to near 15.0V.

And a transformer will have a lot more variation due to loading too.  Would not be uncommon to have an unloaded 12V transformer making 18VAC, which will increase even more after rectification to DC.
G-

[rustkolector]

This project is nearing completion. AC output is working well at 115vac. A DC output is still needed to operate a 0.5 amp 12v computer case fan that will be used for cooling. I was planning on transforming the 115vac output down to about 18-30vac, rectifying to DC, then control the output to the fan with an adjustable LM-317 regulator. However, I understand that transformers are adversely affected by higher frequency. The generator produces approximately 105 hz. Can I just oversize a standard small transformer (if so, by how much?) and get by, or are there other issues? I was also considering using a regulated universal AC adapter for an all-in-one solution for the DC circuit.
Jeff

[ghurd]

The frequency is less than double standard 60Hz.  Should be fine.

Need (or should want to) go lower than 18-30VAC.
 VAC x 1.4 = VDC.   
30VAC goes to (30 x 1.4=) 42VDC, and LM317 blows up at 38VDC input.

A 10VAC transformer would be fine.  14VAC at the most.

LM317 is kind of complicated to get 12VDC.
They make a non adjustable version, 7812, sort of the same thing except the adjusting resistors are in it already.

There is a heat issue too.
Simplified,  317 or 7812 heat is Amps x Voltage reduction.
(30Vin - 12V out) x 0.5A = 18V x 0.5A = 18W
18W of heat in that little thing is going to make Magic Smoke.

Plus, why waste 18W in heat to get 6W usable output?

After the bridge on the DC side, use a big capacitor to keep things smoother.

The simplest way is get a 12VDC regulated output wall-wart.  All the good stuff is in it already.
115VAC in.  12VDC out.

If you are determined to make the thing youself, shoot me an email....
Armpit deep in all that stuff, except for the transformers.
G-

[rustkolector]

It has been quite awhile since updating this thread. This project is finally completed and running better than expected. It is not a wind turbine, but I was able to find the help I needed here to complete this project. This is a 1/10th  scale model of a slow speed 1912 vintage Bruce-MacBeth 100 hp stationary natural gas engine driving a similar vintage alternator modeled after a Westinghouse alternator design. The model alternator core is an Emerson K-55 ceiling fan stator. The alternator rotor uses 18 neo magnets for excitation and produces about 100 watts at 120vac and 750 RPM from each of the two windings. The 4 cylinder engine (1" x 1.12" bore x stroke) was built from bar stock and runs at 625 RPM on propane with an alternator voltage of 100v. The engine easily pulls 40-50 watts (and will pull much more), but runs nicely for demo with a 15-20 watt load. The clear plexiglass inspection door window in the engine is not permanent. It is for watching the splash oil system to select a good oil viscosity and RPM setting to maintain adequate internal lubrication.

I love to model working antique engines doing what they used to do. My thanks to all who helped me with this project. 

Jeff


http://www.youtube.com/watch?v=2-qdar5TEpQ

[12AX7]

Very COOL!

[TomW]

Super Stuff!

Thanks for the share.

Tom

[oztules]

Took 3 times to attampts to reply.... but gee
Damn classy stuff. You need to be proud of that.


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

[Bruce S]

A beauty to watch. I'd leave the plexiglass there for ALL to watch.
Do you build stuff like this for a living?
Thanks for the update!!
Bruce S

[rustkolector]

Thanks and, no, I don't build these for a living. I have always wanted to build working model engines, but I never had the time, or the tools to do it until retirement.

Jeff

[bj]

   Jeff   That is simply awesome.

[12AX7]

Thanks and, no, I don't build these for a living. I have always wanted to build working model engines, but I never had the time, or the tools to do it until retirement.

Jeff

Okay,  why not?  build them for a living?   How many hours do you have in it?   any pics of the building process?

gotta ask, whats your next project?

[rustkolector]

Why not? I guess because it is a hobby, and I want it to stay that way. And, since I am not an experienced machinist I have to take my time. This model took 18 months of part time work to build and another 6 months of tinkering to get it running like the real ones. Building a scale model invariably creates additional problems that take time to sort out. Just figure the volume of a hypothetical cylinder and then scale it to 25%, and see how well the volume scales. Similar issues with flywheel inertia, fuel vaporization, ignition shorts when 18,000 volts gets too close to scale components, etc. Getting a model running well can sometimes takes a long time. These challenges can be fun, but can also be exasperating at times. That's where forums like Fieldlines.com can be so helpful. 

Jeff

[ghurd]

Looks GREAT Jeff!

As long as it is a hobby, it stays fun.
Fun is good.
G-

[rustkolector]

Hi Again,
A year and a half ago I learned a lot on this forum about building a PM alternator from a ceiling fan motor. My thanks again to all who contributed to my success with this little project. A more recent video of this model engine project is show here:

http://www.youtube.com/watch?v=a5yUtb7baOk

I have another new and similar project and again need a little advice. I want to build a smaller PM alternator using a 3.3" dia standard D624 fan motor stator. The motor I am looking at is 230v, 0,4A, 1550 RPM. I am looking for a 15-25 watt 12vdc regulated output at about 375 RPM. One motor manufacturer advertises the D624 frame as a shaded pole design motor. Not sure about other manufacturers designs. My question is, will the shaded pole design hinder using this stator as a PM alternator? Thanks for any insight.

[XeonPony]

I'd use Lexan window! it is amazing to see the internals running!