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600 Watt, 3d-printed, Halbach Array, Brushless Motor

This is a very powerful, 3d-printed brushless motor. The main components like rotor and stator can be printed with a common FDM-printer. Magnets, copper wire, and ball-bearings are ordinary components can be sourced from the links below. The motor is a redesign based on the learnings from the makeSEA Motor. It has 600 Watts, and performs with more than 80% efficiency. 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).

 

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Watch this video to learn more about the design:

 



 

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

 

Building Instructions: 


Assembly Animation:


Test-Run:

Update, Tuning, Testing:

Main Components

Halbach Rotor A 8mm.stl

Slots for magnets. Ventilation outlets. Fixed to shaft. Needs to be strong, not brittle, withstand high centrifugal forces.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 4
Infill: 60-80%
Support: Off

Halbach Rotor B.stl

Closes the rotor and fixes the magnets. Like the lid of a jar. Ventilation inlets. Big ball-bearing.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 2
Infill: 50%
Support: Off

Collar 2x 8mm-13.stl

Firmly locks rotor with shaft. Inludes 2 (smaller) metal shaft collars. Option to attach another component (propeller, pulley) with 4 M3 bolts.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 3
Infill: 70-90%
Support: On

Stator Mount A.stl

Chassis mount. Ball-bearings. Base for winding core. Big vibrations, when rotor badly balanced.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 3
Infill: 70-90%
Support: Off

Stator Mount B.stl

Chassis mount. Ball-bearings. Base for winding core. Big vibrations, when rotor badly balanced.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 3
Infill: 70-90%
Support: Off

Washer M50 0_75mm.stl

If the rotor can move along the rotation axis, one (or more) washers need to be inserted.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 2
Infill: 50%
Support: Off

Stator Core A.stl

Material: Magnetic PLA (Proto Pasta)
Layer Height: 0.15mm
Shell Layers: 2
Infill: 95%
Support: Off

Stator Core B.stl

Material: Magnetic PLA (Proto Pasta)
Layer Height: 0.15mm
Shell Layers: 2
Infill: 95%
Support: Off

 

Accessory Components (3d-printed)

Halbach Rotor A Test Magnet Fit.stl

Small section of the rotor for testing magnets fit, potentially adjust the print settings.

Material: PETG
Layer Height: 0.15mm
Shell Layers: 4
Infill: 60-80%
Support: Off

Spool Top 40mm.stl

Helps to wind copper wire. Space for approx. 50g copper. Fits inside the stator core.

Material: PETG
Layer Height: 0.1mm
Shell Layers: 2
Infill: 30%
Support: Off

Spool Bottom 40mm.stl

Helps to wind copper wire. Space for approx. 50g copper. Fits inside the stator core.

Material: PETG
Layer Height: 0.1mm
Shell Layers: 2
Infill: 30%
Support: Off

Wire Pusher.stl

Never use metal tools to squeeze the wires into the slots (damage isolation). Better use this tool.

Material: PETG
Layer Height: 0.1mm
Shell Layers: 2
Infill: 50%
Support: Off

 

Hardware (parts list):

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Order a Complete Parts Kit from Mash Market

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, whereas the internal forces are almost a factor of 4 below the catastrophic limit.

Detailed Building Instruction

Step 1: Purchase Hardware, Parts-List

20170405_103038.jpg

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.

20170405_105744.jpg Purchase Hardware, Parts-List
 

Purchase Non-Commercial Use License

Order a Complete Parts Kit from Mash Market

 

Or, you can try sourcing your own individual parts here:

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, whereas the internal forces are almost a factor of 4 below the catastrophic limit.

Step 2: 3d-print the Main Components

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 the  makeSEA Mash Market. Please note, that you must be logged in (registration is free) in order to get the files.
 

Purchase Non-Commercial Use License

 

Once you have purchased a License, the individual files and updates will aslo be available direclty from this page.

IMG_7726.JPG IMG_7656.JPG main component
Component                 Material  Layer    Shells   Infill   Support
----------------------------------------------------------------------
Halbach Rotor A 8mm.stl   PETG      0.15mm   4        60-80%   No
Halbach Rotot 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         PLA(*)    0.15mm   2        95%      No
Stator Core B.stl         PLA(*)    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 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

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).

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. 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

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. Nevertheless, if you want to experiment with delta- or wye-configuration, keep all the terminals unconnected.

Wires Scheme v7.5 Wires Scheme v7.6

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

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.

Wires Scheme v6.4 annotated 4-6.png

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

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.

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. 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 side of the rotor.

Select and Sort the Magnets

Step 8: Insert Magnets Into Rotor

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.

Halbach Motor v37 v11.4 Halbach Array v13

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 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.

Final Assembly, Test-Run Halbach Motor v37 v21 copy

Step 10: Variations

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.

Coils in Parallel.pngCoils in Series.png

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.

Average (6 Votes)


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Hi Christoph, recently bought the STL and am slowly printing them off. I am new to 3D printing. Please can you elaborate a little on why you recommend PETG for so many of the parts? I have a reel of PLA and would like to know if its worth buying reels of PETG too.
Posted on 7/24/17 8:24 AM.
Hi Ross, The basic recommendation for PETG or ABS has to do strength, stiffness, and rigidity. Please see the makeSEA Wiki post on the makeSEA Motor designs, which are the precursor to this design, where Christoph talks more about the materials and forces involved. Short answer: printed PLA risks warping or shattering at lower RPM as compared to PETG or ABS. You can certainly build with PLA but, please be careful and prepared for the likely possibility that the motor will fail or shatter (melt?, etc.), at lower RPMs using that material. See also the videos posted on the makeSEA Motor page under the Community -> Showcase, where Christoph spins the motor to it's limits. Wear your goggles and have fun! Please share your findings with us, too.
Posted on 7/24/17 1:41 PM in reply to Ross Lloyd.
Haha oh dear, well in that case I will buy some PETG emoticon Is it also likely to be more geometrically stable than the PLA? I seem to have intermittent problems with the print pulling up from the bed and distorting, which I have tried to fix by increasing the bed temp for the first few layers. Sometimes this works, sometimes not, though perhaps I have my printer in something of a draft!
Posted on 7/24/17 2:49 PM in reply to Maker Support.
Additionally, I read that the magnetic PLA is more abrasive and that I should buy a stainless steel nozzle for my Original Prusa i3. Do you recommend the 1.75mm filament or the larger sizes? Thank you for your support!
Posted on 7/24/17 3:15 PM in reply to Maker Support.
Abrasion is not as dramatical - I've printed quite a lot with a brass nozzle. But clogging might be an issue with cheap brass-nozzles. The metal powder and the plastic is a simple blend: the powder can separate and stick at the inner walls of the nozzle. In order to prevent clogging, it's recommended to print at a nozzle-temperature as low as possible, lubricate the filament, and maybe use a coated nozzle. 1.75mm or 2.85mm filaments are both OK. I'm using 1.75mm for the magnetic PLA.
Posted on 7/24/17 3:31 PM in reply to Ross Lloyd.
Hi Christoph, on the abrasion issue, I am using the original prusa i3 direct from prusa, so it has their stock brass nozzle. Any idea how these are for wear and clogging? Any recommendations on what to lubricate the PETG with? I have a fair stock of silicone spray lying around!
Posted on 7/27/17 4:10 AM in reply to Christoph Laimer.
I still wonder about how much thrust this motor can generate..
Posted on 7/27/17 9:14 AM.
Hi Fabio, we have raised the question with Christoph. Unfortunately, we have not studied that, yet. I'm afraid we don't have a good answer but would love to hear of your findings if you decide to experiment.
Posted on 7/27/17 10:24 AM in reply to Fabio Hasseck.
Hi Ross, the wear issue is related more to the ferrous PLA and the fact that it is a bit more abrasive due to the embedded iron powder. You would have to do a LOT of printing to wear out the head - we've printed hundreds of cores before having to replace it. And, they are relatively inexpensive to find online. As for clogging, we have found that running PLA through a simple filament cleaner/filter - a small chamber with a sponge or paper towel inside that is laced with high-temperature cooking oil (e.g. rape seed), helps to provide a bit of extra bite to the feeders and seems to prevent sticking. Silicon spray would probably also work. We have also found that lower extrusion temperatures sometimes help improve viscosity with some materials. That filament cleaner approach may also work with PETG, however, we have not had to use this trick with PETG on our Ultimaker units, only our MakerBot (which was really designed only for ABS). Hopefully this helps!
Posted on 7/27/17 10:30 AM in reply to Ross Lloyd.
Hi Fabio. I didn't measure the thrust, but according to http://www.godolloairport.hu/calc/strc_eng/index.htm it should be 2.3kg. The thrust very much depends on the propeller diameter - larger props have more thrust. The other factor is the propeller pitch: the larger the pitch, the more power is needed, the faster the aircraft. These are some reasons why a helicopter has a large propeller with a low (variable) pitch.
Posted on 7/28/17 9:07 AM in reply to Fabio Hasseck.
Hi, I would like to double check the cable requirements please. I have 0.45mm copper wire, and have made 5m lengths of 6 strand cables. On the spool the total weight with a PLA spool is ~61g each as opposed to ~50g, and subtracting exactly one run of wire brings me down to 53g. Should there be 5 strabnds rather than 6? Or does the stated 50g exclude spool weight? I am struggling to fit 4 turns of cable over the flattish part of the top of the tooth no matter what I do, so I am wondering if I have the correct amount of wire? It also appears as though you have no twists to your wires in the assembled shots. The twists in the cables are adding to the volume of cable, so if they are not required is there any need for them?
Posted on 8/26/17 6:28 AM.
Ah I think I have misunderstood the guidance on twists, I have put 30 twists over the full length of the cable, does it actually mean put twists in the very end to bind the cables together?
Posted on 8/26/17 7:09 AM in reply to Ross Lloyd.
Hi Ross. Diameter, strands, length, and weight are correct. Maybe there are variations how diameter is specified (with or without isolation)? Twists are mainly needed to not have the strands get tangled while winding - with less twists the slots can be filled denser. Anyway winding is a time-consuming manual work, and I probably should recommend to first try only 5 strands (less fill density requires less careful working). 3 turns are also an option - the resulting nominal voltage fits well with 6S LiPo (instead of 8S).
Posted on 8/26/17 7:25 AM in reply to Ross Lloyd.
Hi Christoph, that looks to be the case, taking a caliper to the wire, I see its outer diameter is 0.50mm, even though its label says 0.45mm, so I assume there is a little more copper in the wire in this way of specifying. I will go with 3 turns - the motor is already hugely powerful and I am only building it for educational reasons really, though perhaps I will print an impeller or a fan for it at some point!
Posted on 8/26/17 8:42 AM in reply to Christoph Laimer.
First off I want to say thank you for the awesome plans at such a reasonable price. Very well done.

I have ordered everything I need to build the motor but I had a question I was hoping you could help me with. I noticed you said you had observed more power when you used magnetic pla for the stator, which I also assume has a very low metal content. This gave me the idea to print the stator in regular pla that I could then make a plaster cast. Then melt the plastic out and either pour an aluminum and iron powder mix (my forge can't get hot enough to melt iron) or mix the same iron powder in an epoxy and inject it into the molds. Maybe 30-50% aluminum/epoxy and the rest iron. Do you think the power gain will be worth the additional effort of casting? I also read motor stators are normally laminated in layers and the more layers it has the more efficient it is. I'm curious to see how having so many individual particles will affect efficiency and power. I plan to document the trial and error process the best I can and will share if anyone is interested.
Posted on 8/30/17 12:25 PM.
Thank you for your reply, I really appriciate it emoticon
I guess a single motor won't have enough thrust for the drone I'm desiging, but maybe 4 will do.
On another note: with what tools/electronic circuits can I measure things such as RPM and temperature? And if small enough is there a way to fit such tools inside the motor?
Posted on 8/31/17 7:24 AM in reply to Christoph Laimer.
I believe he said he used a 20" prop that the motor could spin at 6,000rpm. There are many free calculators online (like eCalc) that will estimate thrust and top speed of props at a given rpm.
Posted on 8/31/17 7:41 AM in reply to Fabio Hasseck.
Hi Fabio, it sounds like you have some very big plans. I think you will find it very useful to build yourself a 250mm quad to start off with and learn how everything works with flight controllers and such. Not only will it be MUUUCH cheaper (you can probably build the entire quad for the price of building one of these motors) but you will also learn how everything works together successfully because I think you will find as you start stepping up the size you will run into many issues that are far more complex than on the small quads. Also for a quad to fly properly, you will need a motor for each prop or you will have to go to variable pitch props which will be a whole different animal to tackle.
Posted on 8/31/17 7:47 AM in reply to Fabio Hasseck.
WAiting fot paycheck so I can get my hands on PETG then I'll make a small quad.
And yes I guess I have few big plans emoticon
Posted on 8/31/17 8:00 AM in reply to Stepehn Coyle.
Hi Stephen, we would love to learn of your results and share them with the project. Feel free to post to your Profile page or contact us for assistance. The more iron contained in your core, the better it should perform up to a point: the distribution of iron is sort of acting as an alternative to the lamella layers in a traditional motor design, to help focus and isolate the magnetic field around the core. Given that the plastic can only contain so much iron due to extrusion issues, there is probably room for improvement in terms of casting a core that is more concentrated with iron powder. As for the aluminum, that is an interesting proposition! You may find that past a certain concentration, the performance degrades because of the phenomenon that traditional lamella layers are intended to combat. We're not sure what the result will be but, would love to hear from you and would be happy to add your discovery to the full project. Thanks for sharing!
Posted on 9/1/17 1:26 PM in reply to Stepehn Coyle.

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About Me

Christoph Laimer

 

makeSEA Chief 3D Designer

Award winning 3D designer, Christoph is responsible for some of the most innovative designs, observations, and insights available on the makeSEA registry. Hailing from Zurich, Switzerland, a stronghold for master tradesmen and creatives since the 12th century, Christoph couples his formal expertise in electrical engineering and software development with his passion for mechanics to design 3D printable mechanical clocks, motors, and a variety of scalable components and usable objects. He is also a primary contributor to the makeSEA wiki and blog, where he records invaluable results and observations from his 3D printing experiments, which are used as a reference manual for other 3D print engineers and enthusiasts.

After completing the masters degree in Electrical Engineering at the ETH, Zurich, Christoph worked as a software developer - initially in semiconductor industries, and later in life science. Designing and creating innovative software, interacting with customers, and managing a small team of software developers was his passion.

Always taken with mechanical constructions, Christoph designed and experimented with RC model airplanes. With the advent of 3d-printing, Christoph found a new type of creativity, focusing on mechanical watches. His imagination and 3D printing allow him to transform his "crazy" ideas into reality. His belief that future watches will be highly customisable - not only engraving, ornaments or decoration, but real complex objects combining mechanics and electronics - has led him to explore and push the boundaries for 3D printing, combining advanced mechanics and pleasing aesthetics in the process.

Christoph Laimer named as Winner of the Share Prize, 2016

Recently, Christoph was awarded the top prize for his 3DPrinted Tourbillon Watch at the Piemonte Share Festival in May, 2016. The Share festival is an international competition that promotes and supports contemporary art in the digital age. Christoph was awarded the top prize for his 3DPrinted Tourbillon Watch.

This attractive domestic timepiece adds flair to any living room, and is a functional Swiss clock that is almost entirely 3D printed. The Watch is open-source, so every working piece of it is open for inspection, on the web and in the home as well.