Vintage generator based on ceiling fan

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xander janssen

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Started building a generator for my 2VD5. Primarily to increase the rotational inertia to lower the rpm without increasing the size of the flywheel.

The rotor comes from the stator of an old ceiling fan. The stator will get permanent magnets.
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Thats a great idea to use a ceiling fan motor! If you can find an early 1900s fan to start with they sometimes have spoked rotors like the generators shown. I think its a great start to a project!
 
Started building a generator for my 2VD5. Primarily to increase the rotational inertia to lower the rpm without increasing the size of the flywheel.

The rotor comes from the stator of an old ceiling fan. The stator will get permanent magnets.
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Not sure what your size requirements are but another source of a motor is a scraped motor from a high efficiency washing machine. Until I repaired my LG washer, I'd never seen such a motor. Rotor has a ring of permanent magnets that mounts like a brake drum over these coils. Bigger though. Motor is like a foot in diameter.
 

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Not sure what your size requirements are but another source of a motor is a scraped motor from a high efficiency washing machine. Until I repaired my LG washer, I'd never seen such a motor. Rotor has a ring of permanent magnets that mounts like a brake drum over these coils. Bigger though. Motor is like a foot in diameter.
The rotor I have is 130 mm (~5 inch) in diameter which is almost perfect to scale 1:10. I will keep the washing machine motor in my mind if I ever need a bigger one.
 
Nice :) !!!, I have an old ceiling fan motor in my garage somewhere(?) just for this purpose, but haven't gotten around to it, glad to see you have :) !!!
 
I am going down the same path using old ceiling fan motors. I'm still in the experimenting stage. I attached the fan stator, which is normally stationary in a fan application, to the crankshaft of my Bruce Macbeth, using a rubber coupler. The surrounding shell, which is usually the rotating part of the ceiling fan, is held stationary. I lined the inside of the shell with rare earth magnets with alternating north-south polarity. There are 14 of them, 4 north and 7 south. I brought the outer winding wires through the motor shaft to a slip ring to extract the power. As soon as I get through another project and put this thing back together, I can shoot some pictures.

Be careful, it puts out a lot of voltage! Not sure how much power and the load line yet, but the voltage is definitely pretty high.

Dan
 
I am going down the same path using old ceiling fan motors. I'm still in the experimenting stage. I attached the fan stator, which is normally stationary in a fan application, to the crankshaft of my Bruce Macbeth, using a rubber coupler. The surrounding shell, which is usually the rotating part of the ceiling fan, is held stationary. I lined the inside of the shell with rare earth magnets with alternating north-south polarity. There are 14 of them, 4 north and 7 south. I brought the outer winding wires through the motor shaft to a slip ring to extract the power. As soon as I get through another project and put this thing back together, I can shoot some pictures.

Be careful, it puts out a lot of voltage! Not sure how much power and the load line yet, but the voltage is definitely pretty high.

Dan
Dan,

Would be great to share some the thoughts.

I'm now look i ng on how the various coils are wound. The aux/starter coil consists of at least two coils and the main 3 speed coil consists of at least 3 or 4 coils.
 
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Shell Stator.jpg

The first image is what used to be the stator, what got fastened to the ceiling. There are only 2 windings. Selecting one or the other changes the speed. There are 4 wires, 2 for each winding. The wires are fed out through the hollow shaft. This becomes the rotor, what gets coupled to my Bruce-Macbeth crankshaft output. The second picture is the shell. That used to be what the fan blades attached to and would spin. There are 2 bearings, one for each half of the shell. By mounting the shell to my base (you can see one of the brackets), this holds the shell and allows the rotor to spin inside. Now because the wires will now spin along with the rotor, slip rings are used. The wires for the outer winding are soldered to each slip ring, and brushes "slip" along the rings to bring the power out. I haven't yet designed the brush mount. I want to make that look vintage and I haven't had time yet. I did take voltmeter probes and touch the slip rings while the engine was running. Lots of voltage. I did apply a resistive load, but because I think my cheapie voltmeter was getting fooled by the weird AC voltage, I need to verify with a good, true RMS voltmeter.

Also, I stuck 2 of the rare earth magnets to the shell, as you can see. The brass ring surrounding the shell hold 14 pairs of magnets, poles alternating - north, south, etc. There are spacers soft soldered inside the brass ring that space the magnets so that they run close to the steel laminations of the rotor. The magnets are so strong that they hold the assembly together without additional fasteners, for the time being. In fact, they are so strong that it's a bugger to get the assembly apart!

I hope this helps.

Dan
 
Dan,

Thanks, this is what I intend to do.

Mine has 6 wires, so I have to figure out which give a decent voltage. Inner and outer coils are connected.

I ruined the outer shells getting the motor open. Next time I know how to do it in a more gentle way. Anyway, I did not plan to use them as I want to go for a more open look.

Regards, Xander
 
Odd thoughts...
  • On "the open look" - you could cut away half the spokes of the casing?
  • On "engine capability" = to drive the generator you can measure cranking torque with a torque wrench.... Dial type will have a "max." reading as you pass poles through the rotation using the torque wrench. Or attach a pulley wound with string, and use some weights and a bit of arithmetic, or a spring balance pulling the string, or if you only have a click-type torque wrench, find the setting where it just pulls the generator over the poles. - Then you can compare the max torque resisting rotation as the minimum torque needed by the generator to get it to rotate... I.E. = max torque resisting the torque wrench. - Try steam pressure divide by piston area and it should give a force, which multiplied by crank radius gives max torque of the engine = max engine torque - derated to 75% boiler pressure for the steam being cooled a bit from boiler to engine maybe?
  • Comparing what the generator needs versus the engine's ability you can determine the gearing - or steam pressure - to run the generator. I should love to know what size engine/pressure/gearing you end-up with. I fitted an engine to my genny, found the engine (oscillator) needed 60 psi, but only worked up to 30psi, so I wasted the time mounting the engine to the genny, when I should have worked-out the numbers first...
And I want an in-line arrangement....
A 1/2" piston at 30psi and 4:1 ratio failed, and I had planned a 3/4" piston at 30psi in-line (only double to torque, not "4 x" to eliminate the gearing of a belt drive). Next engine needs a bigger bore! I.E. 1 1/4in at least for 30 psi. Love to see yours as it progresses.
  • To reduce voltage to a manageable level - and control a stable DC, I picked-up some cheap capacitors and a rectifier/voltage control buck for very few £ on E&ay. - I expect you'll be generating mains AC on yours with the basis that it was a mains AC motor...
K2
 
I will consider the open look at some point. I ruined one shell and snapped a tool bit because my rotary table simply isn't rigid enough.
This was just an experiment for me. I know it can be done, I've seen it before, operating.
I'm a retired electrical engineer, and still a rather fresh model engine maker. At this point in my life I'd rather not throw a bunch of technical stuff at my hobby. That would just bog down the works. To me, there is no need. I just want to have fun learning machining and seeing the results of my work.
This "alternator" is direct coupled to the engine through a spider coupler, that's it. Once everything is back together and working, I'll see what the voltage is versus the load created on the engine, just to the point where it's not bogging the engine. Then I can deal with whatever voltage comes out, and use it to run my radiator cooler fan, maybe some lights, etc. I'll make it pretty and move on to my next build already in progress.
Dan
 
Hi Dan, Sounds like you can handle the electrics better than I can. I had to learn from others on this site.
But all generators (as you will probably know) need to have an engine that can overcome the torque required to overcome the magnetic resistance to the generator turning. Simple measurements and a few simple numbers can tell you if your engine is sufficiently "Torquey" to beat the magnets (and the tiny frictional loads). I and a few others can help if you wish?
Many others here are more expert at machining than I am. So don't be afraid to discuss your failures :(, problems :mad:, queries :confused: and SUCCESSES:D here. We all learn from the failures and successes.
Cheers,
K2
 
I will go for this look.

Stator and rotor-bearings are attached to the base plate which gives a real "open" look and allows careful alignment/shimming in X, Y, Z and Rx and Ry of the rotor with respect to the engine and the stator with respect to the rotor.
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Just an opinion.
I prefer to make a frame for stator that joins to bearings for rotor/shaft, so when I change my ideas I can up and re-locate on a different base plate without having to re-set-up all the alignments. Also, with careful design, all the bearing alignments and frame alignments can be machined precisely where you want them, preferably in a single setting - so alignment is by precise machining and assembly without having to "shim and fiddle" and rely of bolted joints to hold the alignment true. While it is "on paper" (or in your computer) it is easier to adjust the design than when half the bits are made and don't join up as planned.
Enjoy!
K2
 
Hi Dan, Sounds like you can handle the electrics better than I can. I had to learn from others on this site.
But all generators (as you will probably know) need to have an engine that can overcome the torque required to overcome the magnetic resistance to the generator turning. Simple measurements and a few simple numbers can tell you if your engine is sufficiently "Torquey" to beat the magnets (and the tiny frictional loads). I and a few others can help if you wish?
Many others here are more expert at machining than I am. So don't be afraid to discuss your failures :(, problems :mad:, queries :confused: and SUCCESSES:D here. We all learn from the failures and successes.
Cheers,
K2
I've seen Dan's BM engine. It's really nice. It will certainly have enough torque to run the generator as it is designed.
There is another builder in our area that has a similar setup and it runs well too.

Those BM engines are pretty impressive.

Sid
 
Thanks Sid. I don't know about anyone else, but I like the numbers - then making things to prove the "numbers" were right. Just a game I play. - When I just fitted my generator to a "spare (Steam) engine", it didn't run the generator as planned. because it wasn't designed to use the air pressure I tried to apply... and didn't have the torque at max possible air pressure to crank the generator from pole to pole. Then the sums I did proved this was right! - I should have done the sums first... Hence my asking about the torque required for this generator, etc. We learn (or sometimes we don't learn...) from each others mistakes, so I am sharing that experience. - And that's why I'm asking Dan if he has any information on his rebuilt motor as a generator, to compare with engine torque? I expect you are right - but how do the numbers add-up?
K2
 
Carefull reversed engineering (not to damage the thin wires) shows that I'm lucky. The main coil is on the outside and the 2nd phase and coils to reduce speed are all on the inside, so easy to be removed.

2nd though: this is more likely due to design rather than luck, but anyway I'm happy.

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The wheel of a hover board might be even better as it already contains the magnets.

For the price of the magnets I now need for the ceiling fan, one can also buy a 2nd had or broken hover board.

 
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