Introduction: 600 Watt, 3d-printed, Halbach Array, Brushless DC Electric Motor

This is a very powerful, 3d-printed brushless DC electric motor. It has 600 Watts, and performs with more than 80% efficiency. The main components like rotor and stator can be printed with a common FDM-printer. Magnets, copper wire, and ball-bearings are ordinary components. The magnets of the rotor are arranged as Halbach Array. The motor runs with a standard ESC widely used in different RC-applications (plane, drone, car).

Max. power (tested)           600 W
Nominal Voltage                30 V
Nominal Current                20 A
Kv                            255 rpm / V
Efficiency (at nominal power)  80 %
Total Weight                  900 g
Diameter                      105 mm
Length (without Shaft)         85 mm
Shaft Diameter                  8 mm

The motor is a redesign based on the learnings from the makeSEA Motor. For the design I've used Fusion 360, for 3d-printing Simplify3D, Ultimaker 2, and Makerbot Replicator 2x. The referenced videos above show additional information: general demo, building and assembly instructions.

The required hardware (magnets, copper wire, ball-bearings) is available on eBay or AliExpress for roughly $50 (USD). I hope that you also want to support me and my work: I'm selling the STL-files for your 3d-printed motor for $10 (USD). Links to all individual components are provided in the subsequent instructions steps.

I’m really curious to see your applications, comments, and ideas.

Step 1: Purchase Hardware, Parts-List

To get started, you need to purchase some hardware. The hardware isn't very exotic, and you maybe can find it in your local hardware store. I bought most of it from AliExpress, but other online stores like eBay or McMaster are selling these products as well.

Depending on your application you should prepare M3 Bolts and Nuts, Washers, connecting Cables, Heat-Shrink, and Plugs. As tools you need a decent drill-press, a solder iron, various screwdrivers, and a little scale. Make sure your 8 mm drill-bit is in a good shape.

Note 1: The sizes of the magnets indicated by the sellers are a nominal values. In reality the magnets are a bit smaller. The 3d-design of the rotor is optimized for the real size (large magnets: 39.2 x 9.7 x 3.7 mm, small magnets: 19.2 x 4.7 x 2.8 mm). In doubt, contact the seller before ordering.

Note 2: When you’re doing the first test runs, keep an eye on the rotation speed - especially, if you’re using different materials. Better start with a lower voltage battery. If the motor rotates too fast, it could disintegrate, and fast flying debris can cause severe injuries. The expected rotation speed, when the rotor breaks is 15’000 rpm. The suggested maximum rotation speed is 8’000 rpm. At that speed the internal forces are almost a factor of 4 below the catastrophic limit.

Step 2: 3d-print the Main Components

Basically the motor consists of 3 main components, whereas each component is divided into two halves. There is the rotor, the stator core, and the stator mount. All parts can be printed with 0.15 mm layer height. Except of one part, there is no support material needed.

The files can all be purchased and downloaded from makeSEA. Please note, that you must be logged in (registration is free) in order to get the files.

Component                 Material  Layer    Shells   Infill   Support
----------------------------------------------------------------------
Halbach Rotor A 8mm.stl   PETG      0.15mm   4        60-80%   No
Halbach Rotor B.stl       PETG      0.15mm   2        50%      No
Collar 2x 8mm-13.stl      PETG      0.15mm   3        70-90%   Yes
Stator Mount A.stl        PETG      0.15mm   3        70-90%   No
Stator Mount B.stl        PETG      0.15mm   3        70-90%   No
Washer M50 0_75mm.stl     PETG      0.15mm   2        50%      No
Stator Core A.stl         mPLA(*)   0.15mm   2        95%      No
Stator Core B.stl         mPLA(*)   0.15mm   2        95%      No

(*) Magnetic PLA from Proto-Pasta

The ROTOR with the slots for the magnets is the largest part. The second part of the rotor is like the lid of a jar, and holds the magnets in place. The third smaller part of the rotor named “collar” is needed to firmly lock the shaft to the rotor. The rotor needs to sustain a high centrifugal forces, hence I recommend a material, which is strong and not brittle. The shaft collar is the only piece, which needs to be printed with supports enabled.

The STATOR CORE is the winding form of the copper wires. It consists of two symmetrical parts. I recommend to use Magnetic Iron PLA from Proto Pasta. PLA has a problem at higher temperatures, but the metal powder not only helps to increase the magnetic flux, but also helps to dissipate heat.

The STATOR MOUNT is also divided into two halves, it firmly locks the stator core, and allows to mount the motor on a chassis. All ball-bearings sit on the stator mount, and it finally needs to absorb all the forces from the motor (vibrations, torque).

Accessory Components

Since it takes several hours to print the rotor, I recommend to first print a small section, fit in the magnets, and tune the print-settings if needed. There is also a spool, which is very useful for the winding work. And there is my "WirePusher" - a tool that looks like a degenerated spatula.

Component                            Material  Layer   Shells  Infill  Sup
--------------------------------------------------------------------------
Halbach Rotor A Test Magnet Fit.stl  PETG(*)   0.15mm  4       60-80%  No
Spool Top 40mm.stl                   PETG      0.1mm   2       30%     No
Spool Bottom 40mm.stl                PETG      0.1mm   2       30%     No
Wire Pusher.stl                      PETG      0.1mm   2       50%     No

(*) Use the same settings as "Halbach Rotor A.stl"

The material settings for these tools is less critical. You probably can print them also with PLA or ABS.

Step 3: Clean-up, Preliminary Assembly

After all parts are printed, they temporarily should be assembled without the copper wires and the magnets. Most likely there is some work required to fit all parts together.

Use a drill-press to adjust the holes for the shaft and screws. Lubricate the drill-bit, and drill at low rotation speeds - cut and not melt the plastic! The 8 mm bore in the rotor and the collar needs to drilled very careful - it has to be perfectly straight, or there will be a potential problem with a very bad balanced rotor.

Press-in all the ball-bearings. If it’s too loose, you can add some kapton-tape (don’t use painters tape, because it will be flattening and loose its effect).

Fix the nuts on one end of the rods with thread-locker glue.

Push the two halves of the stator cores onto the stator mount, and align the teeth-headers. Temporarily fix them with painters tape for later winding work.

Also check, if the rotor can freely spin, and doesn't touch the stator.

Step 4: Prepare the Wiring

Enamelled copper wire with 0.45 mm diameter is needed. 6 strands are combined into a single cable. It needs to be 5 m long. Twist it 20 to 30 times, and wind it up onto a small spool (provided as 3d-printable accessory component). The copper of one spool will weigh roughly 50g. 3 spools are needed for winding the 3 phases.

I recommend to wire the motor with the wye-configuration, hence the 3 terminals of the cables can already be soldered together, and isolated with heat-shrink. In my tests I've measured quite high circulating currents for the delta connection, causing unwanted high losses. Nevertheless, if you want to experiment with delta- or wye-configuration, keep all the terminals unconnected.

The illustrations show the 3 phases coloured in yellow, red, and blue. The cables are placed with alternating phase and direction into the slots. A single phase consists of 9 smaller coils arranged around the stator.

Step 5: Winding the Stator Core

Phase A: Take the first cable and place it into a slot which has an elongated tooth-head. Fix the loose beginning with some painters tape. Bend the cable into the direction suggested by the tooth-head, skip two slots and place it beneath the neighbour tooth-head into the third slot.

Use a piece of wood or plastic and tightly push the copper wires into the slots. Never use metal tools like a screwdriver, because it damages the isolation. Better use my 3d-printed “wire-pusher”.

Wire the cable back to the slot, where you’ve started. The first turn of the first coil is now completed. Repeat this procedure and make 3 more turns. With the last turn, place the remaining cable inside the stator. It will stay there until the next round.

Phase B: Repeat exactly the same as with phase A, but start with 2 slots offset. The overlapping wires help to fix the wires beneath. When done, also put the spare cable inside the stator.

Phase C: Redo the same pattern again with the third cable.

Great! 1/9 of the winding work is now finished. The rest of the work isn’t much different. Get the spool of phase A out of the interior of the stator, and just continue. Then do phase B, then C, and so on.

When you get to the very last coil of phase C you will realise, that there is something fishy. The cables need to be wired beneath the first coil of phase A. Widen the space with a wooden toothpick, unroll the remaining cable from the small spool, and start weaving!

The result of the weaving work not only looks great, but it also secures ALL the cables.

Step 6: Finish the Stator

Now it’s time to insert the stator mount into the stator core. Feed the 3 begins and the 3 ends of the cables through the holes. You probably need to bend the windings outwards in order to avoid jamming them between stator core and stator mount.

Make sure, the two smaller ball-bearings are well inserted. Also insert the 4 threaded rods with the nuts glued on one side. Be careful to not damage the isolation of the copper wires.

If you soldered already the cables for the wye-configuration, there are only 3 wires to feed through the holes. For finishing the wires, you need to solder some connectors, and protect them with heat-shrink.

Well done! That was certainly the hardest part of the motor.

Step 7: Select and Sort the Magnets

As next, we like to insert the magnets into the rotor. The problem is the variation of the quality of these magnets. They are differently strong and heavy, and this could cause a badly balanced rotor. Therefore we’re going to measure the weight and the force of all magnets first.

Our main tool is a little scale. The absolute accuracy is not as important, but repeatability needs to be good. When measuring magnets with a scale, we have to be careful to not disturb the result by magnetic components of the scale itself. Also avoid any magnetic objects on your desk. Even a screw hidden inside the table could corrupt the numbers. A wooden bar helps to move the magnet away from the scale, and with the law of the lever, the full measuring range of the scale could be used.

Stick all the magnets on an iron bar. Orient all of them with the same polarity, north or south upwards. Label the magnets with a number for later identification.

A simple construction helps measuring the force: Take a wooden bar, and put one end onto the scale, the other end on a block of wood which keeps the bar horizontal. Place the magnet on the bar, mark the exact position, and tare the scale. Push a ferromagnetic object beneath the magnet, also remember or mark that position. I found a piece of ferrite with a similar size like the magnets. Another chunk of metal, for example some nuts, will certainly work as well, but you need to be careful to not magnetise it during the measurements. Tare the scale for each magnet, before measuring the force. Make a note all the values.

For measuring the weight, I’m using a similar construction with a wooden lever like a seesaw. This time the scale needs to be tared only once without the magnet. Also write up all these values.

The plot illustrates the distribution of my magnets. The variation of the magnetic force is very significant but it has no influence on the centrifugal forces (in particular the small magnets are distributed over a wide range: the strongest magnet is almost 3 times stronger than the weakest magnet). However the variation of the weight matters. Imagine, if all the heavy magnets were located to the same half of the rotor.

Step 8: Insert Magnets Into Rotor

Now we’re going to insert the magnets with a special pattern. The picture shows the 18 positions of the slots for the main magnets. But these numbers are not the identification labels of the magnets. They indicate the weight. 1 is the location for the lightest magnet, and 18 is the location for the heaviest magnet. Certainly this sorting method isn’t the optimum for a perfectly balanced rotor, but it’s simple and helps to avoid the worst case.

First insert all the large magnets. Their polarity needs to be alternating. The label on the magnet helps to identify the correct orientation. If a magnet was inserted wrongly, you can easily remove it by pushing a pin through the hole from the other side of the rotor.

Secondly insert the small magnets with the same balancing method as the large magnets. When inserting them, the large magnets will help to find the correct polarity. If the polarity is wrong, the small magnet will float in its slot. Turn it around, and with the correct polarity, the magnet snap to its proper position.

Step 9: Final Assembly, Test-Run

The 3d-printed collar needs to be fixed on the shaft. In fact there is a smaller metal collar sitting inside. The set-screw needs to be quite long and extend into the plastic collar. The collar has 4 additional holes, which can be used to directly mount a pulley or a propeller. There is also a collar available with two internal metal collars. This version can transfer more torque from the rotor to the shaft (see last step with possible variations). Insert the shaft into the rotor and fit the collar into the rotor spokes.

Slide the completed stator into the rotor. Maybe you first try to close the motor without that large 3d-printed washer. If the stator doesn’t slide forth or back, you’re done. In my case the washer was needed - probably the clearance depends on the printer calibration calibration.

Turn the rotor by hand, and carefully listen, if there is some noise from cables, which are touching the rotor. Remove the stator again, and find the reason. Cables are maybe not properly in their slots. Maybe the cables are touching the air-sealing ring of the rotor (see highlighted spot in the drawing).

Basically the rotor is already well fixed when the lid is closed, but if there is a heavy load directly attached to the shaft, I recommend to fix another metal collar on the side of the stator mount.

I also strongly recommend to build a simple, wooden test-stand for the motor. The four threaded rods are used to fix the stator. Don’t tighten the nuts too much, because there is only plastic on the other side. If the nuts come loose while the motor is running, you should use locking nuts instead.

Connect the three wires from the motor to a regular ESC. I’m using my homemade arduino-based servo-tester for generating the control signal. It’s also a good idea to alternatively use an RC transmitter and a receiver - then you can do the initial tests from a safe distance. For the very first test you should really use a battery with a voltage much lower than the nominal voltage of the motor. The motor will spin not as fast, and in case something goes wrong, the damage is less severe. With 8 volts from the battery the motor should be slower than 2000 rpm.

Without a load the motor draws much less than 1 amp. I’m attaching a propeller and let it run in reverse direction, because I want to test the current and not the thrust. For this test I’m initially using again the small battery. Tests at low RPM with the small battery can safely be done indoor, but with the higher voltage from a bigger battery, I recommend to do the tests outdoor.

Step 10: Variations

Different Collars, 5 mm Shaft

There is no real standard for a shaft collar, so I’ve designed a few variations with a different outer diameter. Optionally the motor can also be constructed with a 5 mm shaft. Use the print settings recommended in the according instruction step above.

- Halbach Rotor A 5mm.stl (rotor for 5 mm shaft)
- Collar 5mm-13.stl (for 5 mm shaft, single metal shaft collar, 13 mm OD)
- Collar 8mm-16.stl (for 8 mm shaft, single metal shaft collar, 16 mm OD)

Winding Options

The nominal voltage depends on the number of turns per slot and the number of parallel coils. The maximum current depends on the copper wire section area, and the number of parallel strands and coils. The following table shows some suggested configurations matching with different batteries. The “8S LiPo” version is the configuration, which has been tested in-depth. It is used as a reference.

                  8S     6S     4S     3S     2S
---------------------------------------------------------
Wire Diameter     0.45   0.45   0.45   0.45   0.45   mm
Wire Strands      6      8      12     5      8      #
Turns per Slot    4      3      2      5      3      #
Parallel Coils    1      1      1      3      3      #
Total Wire Area   0.95   1.27   1.91   2.40   3.82   mm^2
Nominal Voltage   30     23     15     13     8      V
Nominal Current   20     27     40     50     80     A
Nominal Power     600    600    600    625    600    W

Wire Strands: When winding your first motor, it’s recommended to use less strands, because the work becomes substantially more simple. The downside is a declined nominal current and power. With more strands it’s more difficult to fit all the cables into the slots. Since I'd like to do more experiments with this motor, I've been winding another core and used 20% more copper wires. I guess that's the upper limit which fits into the slots. That motor still needs to be tested.

Parallel Coils: Decreasing the nominal voltage while maintaining the power is done by lowering the number of turns and increasing the total wire section area. Thick, rigid cables with many strands are painful to wind. It’s simpler to wire the coils in parallel with thin, flexible cables. In order to do this, start like suggested in the basic winding instruction, but already finish when the first third the slots is filled with cables. Prepare 3 new cables, start again with the regular winding pattern, and finish when the second third of the slots is filled. Do the same for the remaining third. Finally there are 9 leads exiting the motor. These leads are now soldered in parallel. The two drawings show the electrical scheme of the motor with the single, and the parallel coils.

PETG Stator Core

If the stator core isn't 3d-printed with magnetic PLA, the rotation-speed per Volt is 15-20% higher. Hence the operating voltage needs to be lower in order to not exceed the specified limit of 8'000 rpm. As a consequence the maximum power of the motor is also 15-20% lower. I don't expect any other disadvantage, when printing the core with a regular material. I'll do some tests later ...

Comments

author
bpark1000 made it! (author)2017-05-04

Awesome design! Here are some suggestions to improve the performance. For the rotor, you really need a metal ring on the outside. The tension in the plastic at 8000 RPM is on the 100's of pounds. plastic slowly yields to this stress, and will fail. Preferably, a steel shell should be used both to withstand the forces, and to provide a return path for the magnetic flux. Since your rotor is made in 2 parts, you can omit plastic and put the ring in place, between the 2 halves.

You also need a "real" flux-return path on the inside of the windings. This path must be laminated. It could be provided by winding in steel wire, as making laminations is difficult.

I noticed a "howling" sound when the motor is running. This is due to harmonic noise, and adds to the loss. You can reduce the harmonic noise by slightly skewing the windings. Probably about half of one of your slot-spacings would be right.

Regarding the magnets: they should not show a wide variation in power! I would look for better quality magnets, such as from K&J Magnetics.

author
TheGoofy made it! (author)TheGoofy2017-05-05

Your hints for improving the performance are absolutely correct.

My motivation to build this motor was driven by the 3d-printing technology: how far can I get, if I'm creating a proper design? And where is the limit when omitting the "traditional" laminations?

Consider the two major factors of losses relevant for efficiency: 1) Copper losses are proportional with the square of the current. 2) Iron losses are caused by eddy-currents, which are (linearly?) related with the rotation speed.

In order to avoid the copper losses, a superconductor would be required. That's difficult to make. For eliminating the eddy-currents it's only needed to leave away the laminations.

Note that this motor has zero iron losses, because there is basically no iron. The magnetic PLA which I'm using for the stator behaves more like a ferrite. It's iron powder in plastique, not conducting. There are only copper losses.

Increasing the voltage (and hence RPM), while keeping the current fixed, will result in in more power and even more efficiency.

Example:

- Nominal values: 30V, 20A, 600W input, 120W copper losses, 0W iron losses => 80% efficiency
- Increased values: 60V, 20A, 1200W input, 120W copper losses, 0W iron losses => 90% efficiency

Unfortunately it's not possible to increase the voltage for this motor. Like you're saying, the fast spinning rotor is the limitation.

But there is the Mark 2 printer (from Markforged), which can 3d-print continuous carbon fibres, and the material is 10-20 times stronger than the material I've used. With 100V and proportional higher RPM (hence better cooling) a current of 30A could be possible. Resulting theoretically in 3kW with 90% efficiency.

Of course there are other factors (e.g. electronics: fast switching FETs), but these are my thoughts to increase the performance ...

author
a_osorio made it! (author)a_osorio2017-07-21

I have access to a Markforged Mark II printer and I'm planning on doing experiments with it to increase efficiency. Which parts would you recommend strengthening and how?

author
TheGoofy made it! (author)TheGoofy2017-07-22

A more robust rotor would allow to use the motor at a higher rotation speed, a higher voltage and a slightly higher current (due to better ventilation). Double the speed, double the power. According to the data-sheet the carbon-reinforced material is 10 times stronger than the PETG. With the centrifugal forces being proportional to the square of the rotation speed, the motor could spin 3 times faster. However it's also necessary to replace the larger ball-bearing with a higher quality bearing - maybe ceramic. And (dynamic) balancing is certainly also required.

author
bpark1000 made it! (author)bpark10002017-05-06

You might want to think about another design I made. One problem I had when designing this type of "ironless" motor is the flux curving back between the poles without linking any coil. The Halbach magnet helps limit this happening in the plane of the magnet, but does nothing to prevent it in the air gap. Instead of having magnet on only 1 side of the coil, have magnets on both inside and outside the coils. The flux is now 'thrown" in from both sides. Now I agree this is difficult to arrange mechanically...unless you change things a bit. What I did was to "twist everything 90 degrees" and have the flux axial, and the current radial. The rotor consists of 2 pancake arrays of magnets, embedded in 2 aluminum discs, each backed with a ring of iron, and the stator a slab with coils embedded inside.

(I built alternator this way to make 120VAC 3 phase 80W, 90% efficiency, to be rectified into 168VDC and fed into "world-wide" power supply. Alternator ran on 1HP engine at 3000 RPM. No circuit breaker was needed as engine stalled if load got too high. Geometry was 4" diameter, 16 poles, 12 coils in 3 sets of 4 per phase star. Weight 1.1 pound. Magnets 1/2 inch square, 1/4inch thick each side, 32 total. No Halbach array.)

Disadvantage of that scheme is it is difficult to arrange for crossing end-turns of the phase coils, forcing you to have only 1 phase in a given sector of the air-gap. But your most ingenious 3D printing guide slots (yours is the best design I have seen to deal with this problem!) could most likely allow crossing turns within the stator plate. On purpose, you would make a 3D print for the stator that is weak and porous, wind in the coils, and impregnate with epoxy. (My opinion to the secret of good 3D prints is the post-processing. I am wearing Mykita eyeglass frames made this way. They are strong enough to not need reinforcing wire in the temples.)

author
TheGoofy made it! (author)TheGoofy2017-05-09

Axial flux is an interesting arragmenent. I'm a bit scared to get the centrifugal forces under control. Maybe it would be worth to just do an experiment, and get familiar with the potential issues ... many thanks for you great ideas.

author
usf.tim made it! (author)usf.tim2017-05-05

Do you have any comparison data to a traditional motor? Say one bought from Hobby king? How much less efficient is your motor? Does your motor weigh less than a traditional motor with laminated core and metal housing? How does it compare in cost?

Thanks Tim

author
TheGoofy made it! (author)TheGoofy2017-05-05

The ratio of power and weight is really inferior compared to a traditional motor. Efficiency isn't as bad - a traditional motor with the same power at 90% efficiency is already a top-quality motor. Costs are difficult to compare, since quite some manual effort needs to be invested. I think the most interesting aspect is, that it's possible to fabricate a good-quality motor from scratch at home. It's not necessary to have a lathe or a cnc-router in your workshop - just a 3d-printer and a drill-press.

author
bliz23 made it! (author)2017-06-01

fyi, proto pasta no longer sells the material under the name "magnetic iron PLA" it is now "Composite PLA - Rustable Magnetic Iron". They say it is the same material, just re-branded.

author
Edgar made it! (author)2017-05-17

Neat. Went to my Blog: https://faz-voce-mesmo.blogspot.pt/2017/05/aulas-de-design-3d-free-class-e.html

author
emissary42 made it! (author)2017-05-14

Have you considered developing a version with a cavity in the rotor for a flux ring? This would be useful for lower speed, higher torque applications.

author
TheGoofy made it! (author)TheGoofy2017-05-15

No. I think the Halbach arrangement partially replaces the flux-ring of the rotor. The weaker side has a less strong and a less extended magnetic field. The rotor has some space to embed continous fibers in order to make it printable with a Mark 2 printer from Markforged (not yet tested).

author
GordonS40 made it! (author)2017-05-14

I'm trying to buy the .stl files from makeSEA but the checkout won't get past "confirm order". Mr. Laimer how do I get the files?

author
TheGoofy made it! (author)TheGoofy2017-05-15

I've contacted makeSEA. They are working on it.

author
nkruger made it! (author)2017-05-11

Greetings Christoph

My compliments with this work. You managed to pull a variety of interesting engineering topics into one project laced with educated design. You are an artist that documents - a rare breed. I procured your plans and would love to do the project with my boys.

NK

author
Melman2 made it! (author)2017-05-07

Great project! A job done by a true engineer. I wonder if an similar design could be used for an wind generator (wind turbine). I think, in that case, the number of rotations per volt should be very low.

author
TheGoofy made it! (author)TheGoofy2017-05-09

Yes, that works. For higher voltage at low rotation speed, only the number of copper wire turns needs to be increased. 10 times higher voltage should be simple. However, it won't be possible to get 600W at a lower rotation speed.

author
Melman2 made it! (author)Melman22017-05-09

Thank you for response. It's obviously isn't possible to get max power at low speed but is ok even at half power. An genuine wind turbine at same power cost much more than this one. The smart arrangement of magnets can be an serious improvement for efficiency of turbine.

author
visent made it! (author)2017-05-06

Woooowww, a great great instructable!!

author
ensarlevent made it! (author)2017-05-06

Best Instructable FOREVER!! Congs..

author
AndrewG166 made it! (author)2017-05-06

this is a "wow factor" design. Very impressive.

author
SuperRistopaha. made it! (author)2017-05-06

Wow! This is a real "Swiss Quality" Instructable! Nowadays many people
find it hard to focus on one subject for a prologed period of time and
dig deep into one subject as sensational distractions are just one touch
screen swipe away... very nice. Thank you for your effort.

author
avayan made it! (author)2017-05-05

WOW! This is brutally amazing. Thanks for sharing this design! I have always wanted to build my own BLDC motor, so rest assured I will utilize some of your techniques! Got a little bit lost on making the wire. I see you are wrapping the strand into a loop, but somehow I am missing how it goes from single stranded to multiple stranded. Will try to watch the videos again and hopefully I get it. Either way, FANTASTIC job!

author
gzumwalt made it! (author)2017-05-04

Very, very nice engineering. I am indeed impressed!

author
Chuckwilcox made it! (author)2017-05-04

Amazing, a work of art. Great video as well. I cannot believe the level of effort and quality of the build. The 3D design modelling as well is brilliant. A incredible piece of work.

author
steveastrouk made it! (author)2017-05-04

How practical would it be to make it by conventional machining ?

author
TheGoofy made it! (author)TheGoofy2017-05-04

For conventional machining I'd probably change the design: in particular the rotor would be too heavy (and unnecessary strong) it it's all in metal. But I guess a full-metal-version with the same arrangement of magnets and copper-wires could perform at 5kW.

author
steveastrouk made it! (author)steveastrouk2017-05-04

Its a beautiful design. I'm impressed with the practical use of the Halbach array.

author
RobotsMaking made it! (author)2017-05-04

amazing! But I have a few questions: 1. how much does it cost to make it (the amount of money that I need to pay for the print plans included) and 2. what for esc can I use for it?

author
TheGoofy made it! (author)TheGoofy2017-05-04

I'm selling the STL-files for $10. If you have a 3d-printer and some spools of filament available, the used material will cost approx. $15. Any ESC will probably work, as long as it supports 30V and 20A. Recommending a specific ESC is difficult, because it depends on the application. E.g. an ESC for a car has a reverse-function, while this is not useful for a plane.

author
Timothee Gillier made it! (author)2017-05-04

Cool motors!

author
maewert made it! (author)2017-05-04

Beautiful work.

I would love to see this adapted to build generators suited for wind turbines.

Best Wishes

author
Ralphxyz made it! (author)Ralphxyz2017-05-04

I wondered what it would take to make a generator.

author
TheGoofy made it! (author)TheGoofy2017-05-04

It works as a generator evenly well like the motor. The electric machine can stay unchanged, just a different electronics is needed.

author
maewert made it! (author)maewert2017-05-04

I am not skilled in generator design. For wind applications I understand that low RPM generators are usually used to eliminate mechanical losses so that the generator is directly driven by the windmill. I'm also under the impression that generator startup force is important which may be due to the generator's cogging forces which would be multiplied also by any gearing if used. To use this motor as a generator without modification I believe would require maybe 50:1 mechanical gearing in order to provide 6k RPMs or so. Is it possible to optimize the design for low RPM?

Thanks

author
TheGoofy made it! (author)TheGoofy2017-05-04

You're right, a gearing is needed to get the 600W from this machine. If only a higher voltage is needed at a very low rpm, it is possible to use thinner wires with more turns per coil. I've done this for an earlier project: https://www.makesea.com/windpowerWriter

author
rudelhutze made it! (author)2017-05-04

Brillant work! Next time i do not have any urgent project i will make one of these !

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samern made it! (author)2017-05-04

This is super super awesome. I have some questions:

1) Can this be scaled up to get to 1KW in some way, either by adding more windings, increasing the length of the motor to do so or some other means?

2) What sort of torque does the motor put out? I know Mechanical Power = Torque x speed (e.g. rad/s). What would the speed of this motor be (at the top end)

3) How well does the motor address heating issues? Does it get warm under load? How much load?

I ask because I have a particular application I'd like to try and I am hoping you can shed some light. I can do a lot by using 4 of these motors, instead of 2 heavier duty 1KW motors.

Thanks!

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TheGoofy made it! (author)TheGoofy2017-05-04

This video shows the motor with 600W input power (30V, 20A):

With 80% efficiency there is 480W pure shaft power. Torque is 0.7Nm and speed is 6650rpm. The ventilation is good enough to dissipate the lost 120W - the motor only gets a bit warm (cool enough to not have a problem with the plastic). I think this motor can perform up to 1kW (40V, 25A, 8500rpm). The rotor will probably be able to sustain the centrifugal forces. However it needs to be dynamically balanced in order to avoid big vibrations.

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samern made it! (author)samern2017-05-04

This motor is beyond awesome! Just terrific. I am going to have to see if it can drive my tank! Ok and a large scale model airplane too! Thanks for the information.

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anapsix made it! (author)2017-05-04

mind blown! Most excellent project and a fantastic level of detail instructable.
You should consider making a kit, with 3d printed parts printed by online shops, perhaps even using metal

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JeffH95 made it! (author)2017-05-04

This is magnificent work; both the end product and the Instructable.

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BobE9 made it! (author)2017-05-04

Amazing instructable. Se need more like this!

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Blackice504 made it! (author)2017-05-04

WOW who would have thought that people would be 3d printing motors.

Nice work, If i ever get a 3D printer i will try this..

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RudolfAlex made it! (author)2017-05-04

Ja, ich würde auch mal als Windgenerator Versuchen, natürlich etwas Stärker im Masstab. Habe auch kein 3D Drucker hier, aber trozdem interessant Dein Proyekt!

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deepsquid made it! (author)2017-05-04

Are you a wizard? Favorited!

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Ralphxyz made it! (author)2017-05-04

WOW, great, Thank You for posting!!

600 watts =0.804613 hp that is amazing.

I am surprised a standard run of mill ESC is all you need.

This gives me so many ideas.

Of course I do not have the 3D printing capabilities but still...

Thanks again,

Ralph

About This Instructable

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Bio: I was born in Zurich, Switzerland, grew up nearby. After finishing my studies in Electrical Engineering at the ETH in Zurich with the masters degree ... More »
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