600 Watt, 3d-printed, Halbach Array, Brushless Motor Print (/documents/96396/246124/M (/documents/96396/246124/MotorIMG_7742.jp otorIMG_7742.jpg/e2a5c1af-ba2a g/e2a5c1af-ba2a-47c7-86cd-f16e -47c7-86cd-f16e619ef8a7?t=149 619ef8a7?t=1491955747000) 1955747000)
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 (/brushless-motor). It has 600 Watts, below. The motor is a redesign based on the learnings from the makeSEA Motor (/brushless-motor) and performs with more than 80% e !ciency. The magnets of the rotor are arranged as Halbach Array. The motor runs with a standard ESC widely used in di "erent RC-applications (plane, drone, car).
Purchase Non-Commercial Use License (/a/7TO-1197-3nE-3o5-a3Q-3om/halbach%20m (/a/7TO-1197-3nE-3o5-a3Q-3om/halbach%20motor? otor? p_p_id=5_WAR_forgecartp p_p_id=5_WAR_forgecartportlet&p_p_lifec ortlet&p_p_lifecycle=0&p_p_s ycle=0&p_p_state=normal&p_p_ tate=normal&p_p_mode=view&p_ mode=view&p_r_p_-4490711 r_p_-449071137_keyword 37_keywords=&_5_WAR_ s=&_5_WAR_forgecartportle forgecartportlet_formDate=14969 t_formDate=1496964 64
Watch this video to learn more about the design:
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Max. Power (tested)
600 W
Nominal Voltage
30 V
Nominal Current
20 A
Kv
255 rpm / V
E!ciency (at nominal power)
80 %
Total Weight
900 g
Diameter
105 mm
Length (without shaft)
85 mm
Shaft Diameter
8 mm
Building Instructions: Instructions:
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Assembly Animation: Animation:
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Test-Run:
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Update, Tuning, Testing:
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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: O"
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: O"
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: O"
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: O"
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: O"
Stator Core A.stl Material: Magnetic PLA (Proto Pasta) Layer Height: 0.15mm Shell Layers: 2 Infill: 95% Support: O"
Stator Core B.stl Material: Magnetic PLA (Proto Pasta) Layer Height: 0.15mm Shell Layers: 2 Infill: 95% Support: O"
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: O"
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: O"
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: O"
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: O"
Hardware (parts list): Purchase Non-Commercial Use License (/a/7TO-1197-3nE-3o5-a3Q-3om/halbach%20motor? p_p_id=5_WAR_forgecartportlet&p_p_lifecycle=0&p_p_state=normal&p_p_mode=view&p_r_p_-449071137_keywords=&_5_WAR_forgecartportlet_formDate=1496964 Order a Complete Parts Kit from Mash Market (https://www.makesea.com/e/6PO-3W5-3nE-1T8A-a3Q-3o5-1T8z/Halbach-Motor-Parts-Kit)
Large Neodymium Magnets (18 pieces, 40x10x4 mm): https://www.aliexpress.com/item/10pcs-40-x-10-x-4-mm-Big-N52-Strong-Rectangle-Block-Bar-Fridge-Magnets-Rare/32622959496.html (https://www.aliexpress.com/item/10pcs-40-x-10-x-4-mm-Big-N52-Strong-Rectangle-Block-Bar-Fridge-Magnets-Rare/32622959496.html) Smaller Neodymium Magnets (36 pieces, 20x5x3 mm): https://www.aliexpress.com/item/10pcs-20mm-x-5mm-x-3mm-N50-Strong-Block-Magnets-Rare-Earth-Neodymium-Magnets-StrongCuboid/32790399928.html (https://www.aliexpress.com/item/10pcs-20mm-x-5mm-x-3mm-N50-Strong-Block-Magnets-Rare-Earth-Neodymium-MagnetsStrong-Cuboid/32790399928.html) Enameled Copper Wire (150g, 0.45mm Diameter): https://www.aliexpress.com/item/100Grams-lot-Polyurethane-Enameled-Copper-Wire-Diameter-0-45MM-Varnished-Copper-Wires-QA-1155/32740810626.html (https://www.aliexpress.com/item/100Grams-lot-Polyurethane-Enameled-Copper-Wire-Diameter-0-45MM-Varnished-Copper-Wires-QA1-155/32740810626.html) Small Ball-Bearings (2 pieces, 8mm inner Diameter, 16mm outer Diameter, 5mm Width, 688ZZ): https://www.aliexpress.com/item/Hot-Sale-10-Pcs-16mm-x-8mm-x-5mm-Steel-Shielded-Deep-Groove-Ball-Bearing-688ZZ/32545084785.html (https://www.aliexpress.com/item/Hot-Sale-10-Pcs-16mm-x-8mm-x-5mm-Steel-Shielded-Deep-Groove-Ball-Bearing-688ZZ/32545084785.html) Large Ball-Bearing (1 piece, 50mm inner Diameter, 62mm outer Diameter, 6mm Width, 6710ZZ): https://www.aliexpress.com/item/The-high-quality-of-ultra-thin-deep-groove-ball-bearings-6710ZZ-50-62-6-mm/32381559782.html (https://www.aliexpress.com/item/The-high-quality-of-ultra-thin-deep-groove-ball-bearings-6710ZZ-50-62-6-mm/32381559782.html) A Shaft (1 piece, 8mm Diameter, 135mm long): https://www.aliexpress.com/item/1pcs-OD-8mm-x-200mm-Cylinder-Liner-Rail-Linear-Shaft-Optical-Axis-chrome-For-3D-Printer/32762873465.html (https://www.aliexpress.com/item/1pcs-OD-8mm-x-200mm-Cylinder-Liner-Rail-Linear-Shaft-Optical-Axis-chrome-For-3D-Printer/32762873465.html)
Shaft Collars (3 pieces, 8mm inner Diameter, 13mm outer Diameter, 5mm Width): https://www.aliexpress.com/item/NEW-20PCS-DIY-8MM-metal-Bushing-axle-sleeve-2-3-g-Weight-Stainless-steel-shaft-sleeve/32514016532.html (https://www.aliexpress.com/item/NEW-20PCS-DIY-8MM-metal-Bushing-axle-sleeve-2-3-g-Weight-Stainless-steel-shaft-sleeve/32514016532.html) Threaded Rods (4 pieces, M4, 85mm long): https://www.aliexpress.com/store/product/7pcs-M4-90mm-M4-90mm-Thread-Length-18mm-304-Stainless-Steel-Dual-Head-Screw-RodDouble/1463832_32744026436.html (https://www.aliexpress.com/store/product/7pcs-M4-90mm-M4-90mm-Thread-Length-18mm-304-Stainless-Steel-DualHead-Screw-Rod-Double/1463832_32744026436.html) Nuts (M4, 8 pieces): https://www.aliexpress.com/item/50pcs-M4-Nuts-A2-Stainless-Steel-Hex-Nuts-To-Fit-Our-Bolts-and-Screws/32789811624.html (https://www.aliexpress.com/item/50pcs-M4-Nuts-A2-Stainless-Steel-Hex-Nuts-To-Fit-Our-Bolts-and-Screws/32789811624.html) 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 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.
Purchase Non-Commercial Use License (/a/7TO-1197-3nE-3o5-a3Q-3om/halbach%20motor? p_p_id=5_WAR_forgecartportlet&p_p_lifecycle=0&p_p_state=normal&p_p_mode=view&p_r_p_-449071137_keywords=&_5_WAR_forgecartportlet_formDate=1496964 Order a Complete Parts Kit from Mash Market (https://www.makesea.com/e/6PO-3W5-3nE-1T8A-a3Q-3o5-1T8z/Halbach-Motor-Parts-Kit)
Or, you can try sourcing your own individual parts here: 18 Neodymium Magnets, 40 x 10 x 4 mm: AliExpress (https://www.aliexpress.com/item/10pcs-40-x-10-x-4-mm-Big-N52-Strong-Rectangle-Block-Bar-FridgeMagnets-Rare/32622959496.html) 36 Neodymium Magnets, 20 x 5 x 3 mm: AliExpress (https://www.aliexpress.com/item/10pcs-20mm-x-5mm-x-3mm-N50-Strong-Block-Magnets-Rare-EarthNeodymium-Magnets-Strong-Cuboid/32790399928.html) 150 g Enameled Copper Wire, 0.45mm Diameter: AliExpress (https://www.aliexpress.com/item/100Grams-lot-Polyurethane-Enameled-Copper-Wire-Diameter-045MM-Varnished-Copper-Wires-QA-1-155/32740810626.html) 2 Ball-Bearings, 8 mm ID, 16 mm OD, 5 mm W, 688ZZ: AliExpress (https://www.aliexpress.com/item/Hot-Sale-10-Pcs-16mm-x-8mm-x-5mm-Steel-ShieldedDeep-Groove-Ball-Bearing-688ZZ/32545084785.html) 1 Ball-Bearing, 50 mm ID, 62 mm OD, 6 mm W, 6710ZZ: AliExpress (https://www.aliexpress.com/item/1pcs-The-high-quality-of-ultra-thin-deep-groove-ballbearings-6710ZZ-50-62-6-mm/32658733911.html) 1 Shaft, 8 mm Diameter, 135 mm long: AliExpress (https://www.aliexpress.com/item/1pcs-OD-8mm-x-200mm-Cylinder-Liner-Rail-Linear-Shaft-Optical-Axischrome-For-3D-Printer/32762873465.html) 3 Shaft Collars, 8 mm ID, 13 mm OD, 5 mm W: AliExpress (https://www.aliexpress.com/item/NEW-20PCS-DIY-8MM-metal-Bushing-axle-sleeve-2-3-g-WeightStainless-steel-shaft-sleeve/32514016532.html)
4 Threaded Rods, M4, 85 mm long: AliExpress (https://www.aliexpress.com/store/product/7pcs-M4-90mm-M4-90mm-Thread-Length-18mm-304-StainlessSteel-Dual-Head-Screw-Rod-Double/1463832_32744026436.html) 8 Nuts, M4: AliExpress (https://www.aliexpress.com/item/50pcs-M4-Nuts-A2-Stainless-Steel-Hex-Nuts-To-Fit-Our-Bolts-and-Screws/32789811624.html) 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 di
"erent 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 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 (/e/6PO-3W53nE-1d2m-a3Q-3o5-1i26/Laimer-660-Watt-3d-printed-Halbach-Array-Brushless-Motor-NonCommercial-Use-License). Please note, that you must be logged in (registration is free) in order to
get the files.
Purchase Non-Commercial Use License (/a/7TO-1197-3nE-3o5-a3Q-3om/halbach%20motor?
p_p_id=5_WAR_forgecartportlet&p_p_lifecycle=0&p_p_state=normal&p_p_mode=view&p_r_p_-449071137_keywords=&_5_WAR_forgecartportlet_formDate=1496964
Once you have purchased a License, the individual files and updates will aslo be available direclty from this page.
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 (https://www.protopasta.com/pages/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). 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
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.
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 toothhead, 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 o "set. 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 di "erent. 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 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
As next, we like to insert the magnets into the rotor. The problem is the variation of the quality of these magnets. They are di"erently 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. 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 setscrew 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.
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 di"erent 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 di "erent 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 di !cult 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.
Related Links This Motor Design: https://youtu.be/XSNmZNlcA1w (https://youtu.be/XSNmZNlcA1w) Halbach Array: https://en.wikipedia.org/wiki/Halbach_array (https://en.wikipedia.org/wiki/Halbach_array) Brushless Motor Basics: https://en.wikipedia.org/wiki/Brushless_DC_electric_motor (https://en.wikipedia.org/wiki/Brushless_DC_electric_motor) DIY electric Motor Hints: http://www.bavaria-direct.co.za/ (http://www.bavaria-direct.co.za/) Electronic Speed Control: https://en.wikipedia.org/wiki/Electronic_speed_control (https://en.wikipedia.org/wiki/Electronic_speed_control) The original makeSEA Motor: https://www.makesea.com/web/claimer/brushless-motor (https://www.makesea.com/web/claimer/brushless-motor) Maximum RPM Test makeSEA Motor: https://youtu.be/WEEDJiC8Jqc (https://youtu.be/WEEDJiC8Jqc) Author Home Page: http://www.laimer.ch (http://www.laimer.ch) Flag
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William Edward Johnson (https://www.makesea.com/c/my_sites/view?groupId=307917&privateLayout=0)
Looks great. I bought the models but some of the links for hardware needed have exorbitant shipping costs because I am in the U.S. Could you find equivalents in the U.S.? Like the threaded rods for example. 0 (0 Votes) Posted on 5/11/17 2:50 AM.
Maker Support Hi William - we have sourced all of the parts for this build and are awaiting their arrival. Complete kits will be available at the Mash Market, shortly. Stay tuned! +2 (2 Votes) Posted on 5/11/17 11:13 AM in reply to William Edward Johnson.
Steve Gaignard (https://www.makesea.com/c/my_sites/view?groupId=314130&privateLayout=0)
That's very nice! Is it correct to say that at 7650 RPM the torque is 0,078 Nm and that at 255 RPM the torque is 2,35 Nm? (without considering the e
!ciency)
0 (0 Votes) Posted on 5/12/17 12:37 PM.
Maker Support A useful comment from Christoph: "The current limit for the Halbach motor depends on the copper wires just like with the smaller makeSEA motor. There is a table at the end of the description with suggested winding options. The current limit is between 20A and 80A." 0 (0 Votes) Posted on 5/15/17 10:25 PM.
EDUARDO DAVID RUIZ PINCHE (https://www.makesea.com/c/my_sites/view?groupId=324507&privateLayout=0)
Hi friend Christoph Laimer, how do I get the plastic modes. Where they sell?. Halbach Rotor A Halbach Rotor B Collar 2x 8mm-13 Stator Mount A Stator Mount A, Etc. 0 (0 Votes) Posted on 5/16/17 7:48 AM.
Matt Ziegenhorn (https://www.makesea.com/c/my_sites/view?groupId=327510&privateLayout=0)
Judging by the board you mounted to in the first video, did you make a larger version or have one planned and went ahead and predrilled the board? 0 (0 Votes) Posted on 5/17/17 7:43 PM.
Fabio Hasseck (https://www.makesea.com/c/my_sites/view?groupId=330398&privateLayout=0)
I've just purchased the license but I can't find the download link.. where is it? 0 (0 Votes) Posted on 5/19/17 6:34 AM.
Maker Support Hello Fabio, a link to download a zip package of the printed files is provided once the purchase is complete with your order summary. You can also find this under the menu
below. If you continue to have problems accessing the files please use the Contact Us form at the bottom of the page to reach Support for further assistance. 0 (0 Votes) Posted on 5/22/17 11:58 AM in reply to Fabio Hasseck.
Maker Support Please select "PURCHASE NON-COMMERCIAL USE LICENSE" button on this page to purchase access to these project files. 0 (0 Votes) Posted on 5/22/17 11:59 AM in reply to EDUARDO DAVID RUIZ PINCHE.
Eduardo Souza (https://www.makesea.com/c/my_sites/view?groupId=281794&privateLayout=0)
Hello, I'd like to ask about the use of Hall sensors in this motor to be controlled by a BLDC speed controller instead of the ESC used in hobby motors. Would the Halbach array supply alternating poles to change the hall sensors state? And what would be the correct placement of the Hall sensors? Thanks 0 (0 Votes) Posted on 6/7/17 7:46 PM.
William Edward Johnson (https://www.makesea.com/c/my_sites/view?groupId=307917&privateLayout=0)
I have started printing the models and the prints so far are superb. I am doing this with my son as a science project so I want to compare the performance with the magnetic pla part and with the part not being magnetic pla. I figure I could set each at a certain RPM and compare their electrical draw. Any comments on this? 0 (0 Votes) Posted on 6/8/17 1:12 PM.
Maker Support Hi William, that's fantastic news! We would love to learn of your findings - please be sure to post to your makeSEA Blog on your Profile page to keep us posted and we're happy to link back to this project. Also, Christoph did a similar experiment early on in our research and you can learn more about his findings at https://www.makesea.com/wiki See the article about the Motor v.0 prototype regarding comparing ferromagnetic and non-ferromagnetic prints of the core. We would love to know what your results are with the Halbach Array motor, too. +1 (1 Vote) Posted on 6/9/17 2:26 PM in reply to William Edward Johnson.
Christoph Laimer (https://www.makesea.com/c/my_sites/view?groupId=96396&privateLayout=0)
Hi Eduardo. I don't think that a Hall sensor works outside of the rotor, because of the "odd" magnetic field of the halbach array. However it certainly works inside. But the current design has no designated place close to the magnets, because I wanted to have all the copper wires as close as possible. The hall sensor needs to be positioned beneath the copper wires. The ventilation channel is 9mm away from the magnets - a sensor could be positioned there without modification of the stator core. Alternatively you could try to make a cavity in the stator core directly beneath the copper wires - that's 4.5mm away from the magnets. Actually that would also be a perfect spot to sense the temperature. Guiding the cables out of the motor is no problem. There are many channels, because of the ventilation system (of course it wouldn't be a good idea to fill all the ventilation channels with cablers). Cheers, Christoph 0 (0 Votes) Posted on 6/17/17 3:31 AM in reply to Eduardo Souza.
Christoph Laimer (https://www.makesea.com/c/my_sites/view?groupId=96396&privateLayout=0)
I made that experiment, but wasn't yet able to compare the e !ciency. So far I know, that magnetic PLA decreases Kv by 15%, which means that the voltage needs to be reduced by 15% (in order to keep the RPM within the specified range). Current and copper losses are the same. So I expect that the motor with the magnetic PLA has 15% more power. +1 (1 Vote) Posted on 6/17/17 3:42 AM in reply to William Edward Johnson.
michael Rinkle (https://www.makesea.com/c/my_sites/view?groupId=386129&privateLayout=0)
given the permeability of the proto pasta magnetic (iron filler) is about 5 to 8 vs 99% Iron of 5000, su cast Iron stator using the lost casting method and pouring real cast iron?
!ce
to say that this motor would be about 100X more powerful with a
0 (0 Votes) Posted on 6/29/17 8:27 PM.
William Edward Johnson (https://www.makesea.com/c/my_sites/view?groupId=307917&privateLayout=0)
OK, so I am on step 3. I live in the U.S. so we use inches. I need a metric drill bit set that includes an 8mm bit. These drill bits need to have a hex shank on them to fit the drill press adapter I designed for this project (I only have a Dremmel press and a power hand drill). I am having trouble locating such a metric set. Does anyone have any recommendations where I can buy it? 0 (0 Votes) Posted on 7/2/17 6:51 PM in reply to William Edward Johnson.
Christoph Laimer (https://www.makesea.com/c/my_sites/view?groupId=96396&privateLayout=0)
I don't know where to get one with a hex shaft. Anyway there are cheap metric drills with uncertain quality from China: https://www.aliexpress.com/item/13pcs-set-2-12mm-useful-Twist-Drill-Bit-Set-High-speed-Steel-Titanium-Plated-Drill-Bits/32686061871.html This seems to be very high quality: https://www.mcmaster.com/#27465a422/=18c5nxw 0 (0 Votes) Posted on 7/3/17 7:47 AM in reply to William Edward Johnson.
EDUARDO DAVID RUIZ PINCHE (https://www.makesea.com/c/my_sites/view?groupId=324507&privateLayout=0)
Hi all, I have a doubt, this motor should have 2 positive and negative poles of 600 Watts DC, as the circuit would be. An electric generator. 0 (0 Votes) Posted on 7/12/17 9:00 AM.
Maker Support Hello Eduardo, this motor design is for a 3-phase motor; essentially, two of each of the three leads become the poles with each pulse. It could work as a generator. Please see our other related Wiki articles and the windpowerWriter Wind Turbine project here at makeSEA for an example of a rectifier circuit that can convert the 3-phase generator output to DC current. In that design, the motor is wrapped more densely with thinner wire to produce a small current at low RPM speeds that can be stepped-up for useful output (e.g., for storage as charge, or to drive an Arduino, in that example). Similar alterations may be of benefit here. A challenge for you: design a suitable rectifier circuit and design modifications to make this Halbach design into a generator, and we will help you to resell those improvements as a kit. 0 (0 Votes) Posted on 7/12/17 1:04 PM in reply to EDUARDO DAVID RUIZ PINCHE.
Fabio Hasseck (https://www.makesea.com/c/my_sites/view?groupId=330398&privateLayout=0)
Out of curiousity, when a propelor like the one you used in the video is added, how much thrust can this motor provide and how much mass can it lift if positioned like helicopter rotor? I'm planning a drone that can carry some cargo (probably things less than 10KG) but I've yet to get PETG to print and measure myself. 0 (0 Votes) Posted on 7/18/17 11:10 AM.
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