Solar Mendocino Motor

Hello! How do you do? This is project HowToDo, my name is Konstantin and today I want to show you how I made a solar Mendocino motor. For those of you who do not know what a Mendocino motor is, it's the simplest brushless motor powered by solar panels attached to the rotor itself. Rotor is floating on kind of magnetic bearings and one side of it is leaning to the wall. I tried to make this motor almost from the beginning of this year. I watched a couple of videos - it looks very simple and easy to repeat, I bought magnets, solar panels, made a base, but it does not work, floating on magnets - yes, but not spin. Ok, I thought problem is in solar panels, bought new one - but had the same problem. So after buying completely new parts 3 times, I was disappointed and forget about the motor for a couple month. But recently I found a video where man making it from some garbage in 10 minutes, and I'm like "whaaaaat, I want to do the same". Actually later he said to me that was he's third try to making a motor. I found everything that is left, turn On the brain, and this time it's finally working and now I share it with you.

Step 1: Necessary Components

Since this thing requires some precision in manufacturing, I give a list of parts and models for printing on a 3d printer in the description, when you have all the parts on hands, the assembly will not take more than half an hour and motor will work with a probability of 99%, 1% in case you messed something up. So we will need:
Solar panels 0.5V 100mA size of 53 by 18 by 2.5mm - http://ali.pub/1yk0ic OR Amazon

Magnets 12 by 4mm with a 4mm hole 7pcs - http://ali.pub/1yk02l OR Amazon

Large magnet 30mm by 10mm 1pc - http://ali.pub/1yk07g OR Amazon

26 magnets 12 by 3mm - http://ali.pub/1yk2m6 OR Amazon

About 40m of winding wire 0.2 - 0.3mm, I have 0.25mm or 30 awg - http://ali.pub/1yk3hv OR Amazon

Also we need guides for the base and for the rotor, I'm using 1/8in ( http://amzn.to/2gPnHxy ) 3/16in ( http://amzn.to/2gJo8G5 ) aluminum rods, but in case you can't find it, I leave the 3d models made in sketchup it's free and very simple program so you can easily remake a models for guides you are using. Plus, if I'm not lazy, I'll make another model without guides in the base, but anyway you have to find non magnetic rod for the rotor, it works with the ballpoint pen refills, but it's very flimsy and it's not the best option.

Step 2: Assembling the Rotor

So when we have all parts, we can start an assembling. The first thing that can be done, but not necessarily, is to select solar panels by weight, I had a maximum spread of about 1 g, which affects the vibration during rotation, but in anyway it's not critical and easy to fix. Next, I solder the solar panels with pieces of wire about 5 cm in length, in pairs, + to - . Try them on the frame and twist the wires in the middle so that they stretch, solder the place of twisting. Fix prepared panels on the frame with an elastic band and glued with super glue, just a couple drops will be enough.

Step 3: Winding

Pass the guide into the rotor frame and you can wind the coils, they are made in one direction and contain 110 turns, the arrows with the dot is the beginning of the winding, I wind every new turn on the other side of the guide, you can wind 10 turns and change the side, it will be easier, the wire is thick enough to wind it comfortably.

Step 4: Balancing the Rotor

When the winding is finished, it is necessary to balance the rotor, I took two blades for the knife, slowly rolled the rotor on them and glued the solder pieces to the sides. I sharpen one end of the rotor guide with a file so that it has the smallest contact with the support wall.

Step 5: Assembling the Base

I begin the assembly of the base, first I made a test and did not cut off the rods, just slide the printed details on rods. Install the magnets by this schematic. How to find the pole of a magnet? Very simple, you need a compass, a magnetic compass in your phone will work, just don't bring it close, knowing that the opposite poles are attracted - we mark out one magnet and find poles on the others with it. On the rotor probably have to put a bit of tape to hold the magnets.

Step 6: Test

Well, in theory, it should start spinning if you shine on one side of the rotor. Interesting moment, I spend the day, trying to understanding why it's not working, even everything was perfectly assembled. The thing was that I have in my studio two 200W softboxes with energy-saving lamps it's a lot of light from them, but motor is not working with it, although I have a voltage on solar panels. I make it work from a flashlight, later from the flashlight of the phone, from sunlight (which seems to be obvious) from a table lamp, from almost any source light other than these softboxes, keep this in mind.

Step 7: Finish

Ok, the only thing is left, to bring our motor to a nice look, cut off the rods, grind them, glue the magnets, cut the tape on the rotor and reassemble, I did not glue the base it's holds good without it, I only glue the support wall. Well, that's it, you can enjoy the work done. A little later, I attached the propeller to it, although it doesn't really blow but it looks funny. Also if you don't want to build it by yourself, you can buy same motors (Or on Amazon) they are pretty cheap actually. That's all I got for today, hope you like it. See you next time!

Find me on social media:

https://www.youtube.com/c/HowToDoEng
https://www.instagram.com/konsta.kogan/

Comments

[KristianK30]

What's the reason for having more levitation magnets in one side than the other?

I assume it gives the axle a slight tilt, but what's the purpose of that?

[wobbler]

I suspect the difference is to keep the axle as level as possible but still provide a force toward the pivot point where the axle meets the end plate. It's difficult to tell from the photo, but it also appears that the coils are closer to one set of magnets than the other. As a consequence, one bearing is taking more of the weight than the other so to keep it level it needs more force and hence more magnets. There is a lot of nudging involved in balancing these things so they work as efficiently as possible- more fun all round!

[rohitk122]

Can we use 4V 100mA solar panels instead of the one mentioned above. If yes, then please tell if any changes is required in the design. Thank You.

[ianmazzu]

You can use any solar panel, the idea why the solar panel it's to get electricity throw the coil, when it's get inducted(the coil) generate an electromagnetic field, and when it does it's start intereacting with the magnetic field of the magnets, and so start rotating it's self. Therfore as u can see, you could use any panel but obviously you'd have to change the design. Could use just a battery inside the coil too, but also is needed to change de design of the coil. With that said, u will notice that in the video he say is need to balance the coil, this is very important also, if u do this part wrong it could no rotate at all!! So if u're going to test ur panels with this coil take into account. Good luck!

[wobbler]

For clarification, you can't just replace the photocell with a battery within the coil without also adding something that controls the power through the coils to turn them on and off at appropriate times. This is why the commutator is used in a normal electric DC motor or Hall Effect switches in non-commutator type motors.

This design doesn't need a commutator because the photocells themselves effectively are also acting as switches by only providing power to their own coils when facing the light. As a result, this motor assumes the light is coming from above generally. If it was lit from below the motor shouldn't turn as the photocell would be activating the coil when it faces the magnet and would stick there.

[rohitk122]

Thank you very much for your reply. I will keep the mentioned point in mind while making the prototype.

[Bruce McCarthy]

Great instructable, really clear and easy to follow. This is definitely on my to-do list.

Would it be possible to angle the bottom support magnets so that the motor does not need any contact at all?

[wobbler]

The short answer is no, not with a passive system. The longer answer is in the references and is called Earshaw's Theorem. The first one is a good overview of magnetic suspension and bearings, the second on specifically about Earshaw's Theorem. Basically, what it means is it can be balanced, but it is unstable so the slightest perturbation will cause it to become unbalanced (imagine balancing a needle on its point on a piece of glass). It can be done though by using controls and feedback which is how those desk toy globes that seem to hang in space work.

The first reference also makes a few interesting comments about using superconducting materials so maybe we'll see some interesting developments in this once (if?) they get effective room temperature superconductors. The third reference shows superconductor levitation in action.

ref:
https://www.sciencedirect.com/topics/engineering/m...

https://www.google.com/search?channel=fs&client=ub...

https://www.youtube.com/watch?v=X5EoUD-BIss

[GrahamRounce]

What are the "26 magnets 12 by 3mm" for?
Call me blind, but I don't see any reference to them, except in the parts list!
Thanks,

[wobbler]

I've got this from the photos and knowing how these work. The 7 magnets are used on the shaft as bearing magnets. The large magnet is used beneath the field coils and is what provides the turning force. The 26 magnets are used in the holes in the bases beneath the bearing magnets to provide the balance force against the shaft magnet. As i26 is not divisible by 4 and the shaft has 3 magnets on one end and 4 on the other, I suspect the author uses different numbers of magnets at each side, maybe 6 under the 3 side and 7 under the 4 side?

A graphic type drawing of it blown apart would be useful.

[bobo328]

Can somebody explain the winding? That picture is not enough to me.

[ianmazzu]

Nice done dude!

[slimjed]

Hey, I had a question about the winding.

you connected each two plates + to -

then how were the two pairs and the wire connected?

Can you provide a drawing please?

[carlos66ba]

Great instructable and a wonderful idea! I have one question: it seems that you have things connected so that it works with light coming from one side (this powers the coils and switches them as the thing rotates). Very clever and explains why it does not work well with the big lights. However, do you think it may be possible to do the switching by electronics so that all the solar panels being illuminated generate power?

[swarley]

I really like this design and have printed the plastic parts and ordered the electronics. Other plans that I've seen have the solar panels wired to the end wires of the winding coils. I don't see anything in your instructions to indicate that you've done this - did I miss something? don't they need to be attached for a proper current? Thanks!

[kylegilbert]

Awesome build! Wasn't familiar with the Mendocino motor design, so this is especially impressive to me.

[bolsoncerrado]

How many rpms did u get!? wow it looks quite fast!! How could you reuse the movement!?

[Intensescroot]

A flywheel could be added to a very large model of this in order to have enough torque to turn, say, a generator. Just the rotor turning freely would stop if a load was applied.

[EmilA1]

The number of magnets dont add upp...

[Intensescroot]

‘up’