Build a Motor DIY - No Machine Shop Needed

[Carl Sieg]

TL;DR Summary

I wish to build an electric motor, and have looked for guides. I’ve only seen “simple electric motor” guides, or ones that need machine shops/advanced equipment. Do you guys know of any resources to help me build a non-simple motor without need of advanced tools?

Hello everyone,

I wanted to build an electric motor, and I have done quite a bit of research on it. However, all the links that I get are for “simple motors”, which are essentially just a D battery, a kitchen magnet, and coil of copper wire. I have tried these already, but I wanted to build a “real motor” if that makes sense, with a stator/rotor/etc. The very few websites I found that weren’t about simple motors had designs that required a machine shop. All the books I found in the library were about the theory of motors, rather than the practical. Do you guys know of any resources/have any tips to help? I don’t have access to a machine shop, but I do to a 3D printer. Thank you so much!

 

[onatirec]

Depends on how detailed you want to get. Tolerances on lamination steel are very tight and cutting requires expensive tools. But you could probably buy a rotor & stator stack online and wind it yourself. You could likely find many components online that would work together as a complete motor, you could probably even 3D print a housing or endbells to hold it all together... Alternatively, you could take a motor apart and try to rewind it and then rebuild it?

Do you have resources you could link that require a machine shop? The heart of the motor (rotor and stator) generally do not require machining. A shaft likely would, but probably you could find something off the shelf somewhere. And the rest of the parts could likely be purchased (bearings, commutator) or printed (housing, endbells).

 

[sophiecentaur]

Welcome to PF. AS long as you can get hold of a couple of strong magnets (easy these days) and some enamelled copper wire (about 0.5mm thick). There are dozens of youTube videos which range from very very basic and others which you could say need a machine shop. This one is as basic as it gets, and will work if you realise that the wire has to be enamelled (i.e. covered in insulating shiny 'paint') and also that one side of one end of the wire ends needs to be cleaned off and the other needs to be coated still. The other end is totally cleaned off. I read the comments and people couldn't get theirs to work and it's almost certainly because they didn't grasp that the half stripped end acts as a switch (commutator). Current only flows for half of each cycle of rotation when the stripped side is on the paper clip support. The coil gets a kick once every turn.

Once it works, you may need to make a better one; and a better one etc.. Eventually you buy machine shop equipment .

 

[sophiecentaur]

TL;DR Summary: I wish to build an electric motor, and have looked for guides. I’ve only seen “simple electric motor” guides, or ones that need machine shops/advanced equipment. Do you guys know of any resources to help me build a non-simple motor without need of advanced tools?

I don’t have access to a machine shop, but I do to a 3D printer.

A 3D printer can produce an insulating frame but any serious DC motor will need laminations; steel parts give you circulating currents (eddy currents). I think you may need to change your terms for this project. Even with the sort of machine tools you might be expected to afford, you'd find it a lot easier to make yourself a steam engine or a Stirling engine. I think there's a clue here if you look at what hobbyists make. It's nearly all brass and steam and requires a decent lathe, minimum.
A motor from a kit would be possible of course; there are a number of those on sale but would that satisfy you? Winding copper wire is very fiddly and you can never seem to get enough wire into the slots. I did rewind a broken Scalextrix car motor but it didn't go as well as the other one of the pair of cars.

 

[Rive]

I wanted to build a “real motor” if that makes sense, with a stator/rotor/etc. ... I don’t have access to a machine shop

The very soul of electric motors (which makes sense) is the magnetic circuit, and to make that right you need to machine and fit iron sheets with high precision. As it was already stated above, without a machine shop (or, rather: without pre-machined precision parts) it's just an uphill battle.

... and that's just the machining.

 

[Tom.G]

A small step up from the "kitchen magnet" approach is to replace that magnet with an electromagnet, a coil of wire around a small (or large) screw (or bolt).

The electromagnet can be wired either in series or parallel with the rotor. You may have to reverse the polarity (swap the wires) of the new field electromagnet to get the motor to run.

You can also experiment with the relative rotational positions of the brushes/commutator with respect to the field.

An added experiment is to wind a 'Compound wound' motor. A Compound motor has two windings for the field, one in series with the rotor. The other winding is in parallel with either the battery supply or the rotor.

The advantage of a Compound wind is it can stabilizes the rotor speed when the load on the motor changes.

And then, if you want to get technical, you could take speed versus load data, perhaps graph it, then find the best ratio between series and parallel winding for least speed variation with differing loads.

There are a few possibilities for building, learning, and being entertained by a 'simple' motor.

Please post your progress and/or results (we like to learn too!).

Cheers,
Tom

 

[sophiecentaur]

A small step up from the "kitchen magnet" approach is to replace that magnet with an electromagnet, a coil of wire around a small (or large) screw (or bolt).

The humble electric motor is in fact a pretty sophisticated device when it's designed properly. They were making electric motors long before the electronics industry started up and the only thing that prevented them from being more extensively used for small devices was probably the lack of suitable power supplies. It had to be Mains or very inadequate batteries. But even then, they were made 'properly'. Without a good magnetic circuit (as stated above) they're really no more than a school demo.

The suggestions in your post would provide entertainment (of course) but I'd bet that quantitative measurements of performance would be difficult because of the low efficiency. Even a home made electromagnet is way outperformed by a cheap modern permanent magnet so the relationship between series and parallel wound AC/DC motors is no longer too relevant these days.

Alternative: If the OP can get hold of a (safe) low voltage, low power AC supply (say 6V 5A wall wart) then it would be easy to make a synchronous motor with a rotating permanent magnet and an AC fed stator. 'Everyone' had them in their electric clock on the mantlepiece until the 60's and they go round once every cycle of the mains. Quite a cool design which requires no brushes or commutator etc etc. In the old days, the mains supply frequency was maintained to high accuracy so that the cycles delivered to each home ensured that all clocks were synchronised to GMT.

 

[Rive]

more than a school demo.

Though without that 'makes sense' requirement it's a different beast - with aiming for aesthetic instead of engineering, good visual impact might be reachable with just button magnets, copper- and iron wires, 3D printed plastic housing...

Wrapping a maglev into a circle won't make much engineering sense but might be cool enough...

 

[sophiecentaur]

Though without that 'makes sense' requirement it's a different beast - with aiming for aesthetic instead of engineering, good visual impact might be reachable with just button magnets, copper- and iron wires, 3D printed plastic housing...

Wrapping a maglev into a circle won't make much engineering sense but might be cool enough...

It all depends on what you want. If you want visual impact then you can easily make a motor that will rotate (various levels of complexity). No lamina required.
"Wrapping a maglev' implies a maglev system which will need lamina - Catch 22, I'm afraid. If a real motor is too difficult the a maglev is many times harder.

 

[Rive]

Right. Should be 'linear motor' instead, maybe. Something like that. Just a passing thought.

Anyway, point is: with electric motors being such a surprisingly simple and yet sophisticated devices, attempting to build one which 'makes sense' does not really 'makes sense'. They are procured or salvaged or such, at far lower price and in higher quality than anything possible DIY.
A different kind of 'sense' required to justify the attempt.

 

[Carl Sieg]

Depends on how detailed you want to get. Tolerances on lamination steel are very tight and cutting requires expensive tools. But you could probably buy a rotor & stator stack online and wind it yourself. You could likely find many components online that would work together as a complete motor, you could probably even 3D print a housing or endbells to hold it all together... Alternatively, you could take a motor apart and try to rewind it and then rebuild it?

Do you have resources you could link that require a machine shop? The heart of the motor (rotor and stator) generally do not require machining. A shaft likely would, but probably you could find something off the shelf somewhere. And the rest of the parts could likely be purchased (bearings, commutator) or printed (housing, endbells).

Hello, thank you for the response! https://www.instructables.com/Make-Your-Own-Miniature-Electric-Hub-Motor/ This is the article I was going to use (Step 8 details the materials/tools needed). Do you have any resources/tips on building a motor this way? (I'm a beginner, and I've never built a motor before). Thank you and have a great day!

 

[Carl Sieg]

Welcome to PF. AS long as you can get hold of a couple of strong magnets (easy these days) and some enamelled copper wire (about 0.5mm thick). There are dozens of youTube videos which range from very very basic and others which you could say need a machine shop. This one is as basic as it gets, and will work if you realise that the wire has to be enamelled (i.e. covered in insulating shiny 'paint') and also that one side of one end of the wire ends needs to be cleaned off and the other needs to be coated still. The other end is totally cleaned off. I read the comments and people couldn't get theirs to work and it's almost certainly because they didn't grasp that the half stripped end acts as a switch (commutator). Current only flows for half of each cycle of rotation when the stripped side is on the paper clip support. The coil gets a kick once every turn.

Once it works, you may need to make a better one; and a better one etc.. Eventually you buy machine shop equipment .

Hello sophiecentaur, thank you for your reponse! I already tried building a motor similar to the one you have linked, and it worked for me! What steps would one have to take to make the motor in the video more complex/powerful?

 

[Carl Sieg]

A 3D printer can produce an insulating frame but any serious DC motor will need laminations; steel parts give you circulating currents (eddy currents). I think you may need to change your terms for this project. Even with the sort of machine tools you might be expected to afford, you'd find it a lot easier to make yourself a steam engine or a Stirling engine. I think there's a clue here if you look at what hobbyists make. It's nearly all brass and steam and requires a decent lathe, minimum.
A motor from a kit would be possible of course; there are a number of those on sale but would that satisfy you? Winding copper wire is very fiddly and you can never seem to get enough wire into the slots. I did rewind a broken Scalextrix car motor but it didn't go as well as the other one of the pair of cars.

I will look into steam engines/stirling engines as well. I wanted to build a motor for two reasons. First, I wanted to learn more about motors and get some practical, hands-on experience. Second, I wanted to be able to implement a motor that I built into some of my other projects. Buying a motor off the shelf could satisfy the second goal, but if building a motor is out of reach with my current resources, do you know of any other beginner projects that don't require a machine shop (in addition to steam/stirling engines). Thank you!

 

[Carl Sieg]

The very soul of electric motors (which makes sense) is the magnetic circuit, and to make that right you need to machine and fit iron sheets with high precision. As it was already stated above, without a machine shop (or, rather: without pre-machined precision parts) it's just an uphill battle.

... and that's just the machining.

Thank you for the response! If building an electric motor is off the table, do you know of any other projects for a beginner like me?

 

[Carl Sieg]

A small step up from the "kitchen magnet" approach is to replace that magnet with an electromagnet, a coil of wire around a small (or large) screw (or bolt).

The electromagnet can be wired either in series or parallel with the rotor. You may have to reverse the polarity (swap the wires) of the new field electromagnet to get the motor to run.

You can also experiment with the relative rotational positions of the brushes/commutator with respect to the field.

An added experiment is to wind a 'Compound wound' motor. A Compound motor has two windings for the field, one in series with the rotor. The other winding is in parallel with either the battery supply or the rotor.

The advantage of a Compound wind is it can stabilizes the rotor speed when the load on the motor changes.

And then, if you want to get technical, you could take speed versus load data, perhaps graph it, then find the best ratio between series and parallel winding for least speed variation with differing loads.

There are a few possibilities for building, learning, and being entertained by a 'simple' motor.

Please post your progress and/or results (we like to learn too!).

Cheers,
Tom

Thank you for the response! A compound motor sounds interesting and doable. Would it be possible for you to send the names of resources for beginners I could use (such as a book or website)? Thank you and have a great day!

 

[berkeman]

Second, I wanted to be able to implement a motor that I built into some of my other projects.

If building an electric motor is off the table, do you know of any other projects for a beginner like me?

Great stuff. What kinds of other projects do you have in mind? If you were interested in electronics, I'd be suggesting Arduino projects or using other microcontroller boards to implement some fun projects. But it sounds like you are more interested in the electro-mechanical side?

Are you in school right now? If so, what level are you currently in your schooling? Does your school have things like a Science Club or other types of clubs?

 

[sophiecentaur]

I will look into steam engines/stirling engines as well.

There are some very nice looking Stirling engine kits. They are quirky and work with safe temperatures and pressures and are an excellent conversation piece. They cost a few bob though but you can impress visitors by running them off a cup of hot coffee.

 

[Tom.G]

Would it be possible for you to send the names of resources for beginners I could use (such as a book or website)? Thank you and have a great day!

Well, I'm going to take the lazy way out on this!
https://www.google.com/search?hl=en&q=homemade+electric+motor

 

[Carl Sieg]

Great stuff. What kinds of other projects do you have in mind? If you were interested in electronics, I'd be suggesting Arduino projects or using other microcontroller boards to implement some fun projects. But it sounds like you are more interested in the electro-mechanical side?

Are you in school right now? If so, what level are you currently in your schooling? Does your school have things like a Science Club or other types of clubs?

Hello,
Since building an electromagnetic motor might be a little out of reach at the moment, I am going to try to build an electromagnet (that’s more powerful than the standard iron nail + couple copper coils).

 

[Carl Sieg]

Well, I'm going to take the lazy way out on this!
https://www.google.com/search?hl=en&q=homemade+electric+motor

Hello Tom,
Thank you for your response.
I have already built multiple simple electric motors, like the one you have posted the link to. I was hoping for a guide for a more complex one. However, many people in this thread told me that it is a bit out of reach at the moment, so I am going to try something new.

 

[Carl Sieg]

Thank you everyone for your help! I really appreciate it.

 

[Rive]

I was hoping for a guide for a more complex one.

Erm... The problem is that the way you stated your request kind of induced an instinctual response from engineers about real motors. Motors which makes sense.

There are plenty of pet/hobby projects which does not makes sense. Still, when pushed to extreme, they require quite a skill, while remaining at DIY level.

I think you can make a motor electric to mechanical energy converter DIY.
We may be able to help.
But to make your thing it's better if you can come up with the idea of the device you want to build.

 

[sophiecentaur]

Still, when pushed to extreme, they require quite a skill, while remaining at DIY level.

So many of the bright ideas that are presented / demonstrated in mags and progs are a waste of time because they just don't work. I say that as someone who can make most things work, despite their naffness. I used to feel really sorry for Science teachers trying to work to a lesson plan with rubbish supplied equipment and getting a class of kids to get the 'right result'.
Plus, the more hamfisted ones would be the last teachers to practice before the lesson!!

 

[Vanadium 50]

I was hoping for a guide for a more complex one.

Complexity for its own sake is never good.

If you want some other feature - lift more weight, spin faster, no initial spin-up needed, whatever, it might make sense to add complexity.