After successfully building a brushless controller i have decided also to build my own brushless motor. Autocad Inventor 3D cad software was used by me to design 3D model of the motor.

Before start to design something you need to know the RPM needed,torque needed,running voltage, max Amps. This formula is for calculating the torque if you have the power and the speed. motor Torque foruma  After reading the gear ratio on  Opel Agila it resulted that i need a speed of 4000RPM to reach 73.4Km/h in 3-rd gear ( i do not need more than that in a city). I decided to make a reverse outrunner motor design because is more easy to cool the stator if is outside. If the sator is inside is more difficult to cool down. The draw-back is that you loose torque because you have a smaller diameter of the rotor. I opted for a 48 slots (teeth) and 40 magnets design and i will have 142.5Nm of torque.

  • Nominal Power: 45KW
  • Nominal Voltage: 230v
  • Nominal current:200A
  • Winding configuration : Delta
  • RPM: 2600
  • Torque 165Nm
  • Construction : 48 slot, 40 Magnets Neodymium
  • Lamination Grade M330
  • Cooling : Glycol
  • Weight: 17Kg
  • Cooper weight ~ 2.7kg

Windings:

  • Can be : delta or Star ( WYE)
  • Delta connection will give you higher power per cooper amount, higher RPM, higher current, lower phase voltage.
  • STAR will give you lower RPM, higher torque (1,73 more than dela) , higher the voltage, lower the current.
  • Can be: concentrated or fractional slot type.
  • If there are concentrated can be: LRK, distributed LRK etc.
  • A good winding scheme calculator can be found here.

winding scheme calculator

 

 

 

 

How to choose the magnets ?

After you choose the slots and poles, you need to choose the magnets. This is not very easy task because you need hi temperature magnets and are not so cheap and easy to find for your needed size. I bought custom made magnets from a Chinese website.

  •  The temperature rating for Neodymium is only a guide value. The actual temperature where magnet start to loose strength is size, shape and magnetic circuit dependent. If you have a magnet attached to a piece of steel  i will demagnetize at higher magnetic flux than in a free space.  On the other hand demagnetization temperature will be  lower if you subject the magnet to a strong opposite magnetic field such in a motor.
  • If the thickness of the magnet is bigger and  you will need a bigger magnetic field to start demagnetize it.

Temperature classification for neodymium magnets, N stays from Neo from .

  • N42           ≤80℃                                      magnet
  • N42M      ≤100℃
  • N42H       ≤120℃
  • N42SH     ≤150℃
  • N42UH    ≤180℃
  • N42EH     ≤200℃
  • N42VH    ≤230℃

Neodymium magnets needs a coating otherwise they will rust in contact with air.

The coatings can be: Nickel, Zinc, Phosphate, Epoxy, Gold and others.

 

Mathematical magnetic flux density analysis.

Next step is to run mathematical analysis in magnetic field to see if i have some areas with saturated magnetic field. We want to avoid core saturation. For this i used Finite Element Method Magnetics Tool A Windows finite element solver for 2D and axisymmetric magnetic, electrostatic, heat flow, and current flow problems with graphical pre- and post-processors brushless simulation FEMM motor simulationWe can observe that i have areas in pink color with to much magnetic flux, above 2Teslas, so i need to increase the thickness of the tooth to stay under 2 Teslas because the saturation of the laminations.

Multiple factors can have a huge difference in motor performance and efficiency:

This factors can be:

1. Maximum working frequency (depending on RPM and no. of poles). The frequency is calculated by next formula:

f= rps (motor rotation per second) x (nr. of poles/2). no.of poles is equal with no. of magnets.

Example for 1000Rpm: the rps will be 1000rpm/60s = 16,66 then  f=16,22 x 40poles/2 will result in: f= 333.2Hz

Because the losses in the core lamination are increasing  with increase (non linear) in frequency we want to have a frequency as low as possible for max motor RPM.  For exampe for lamination grade M330-50 the losses at 50Hz and 1Tesla are 1,29W/kg but 132W/kg at 1000Hz.

2. Proper combination between slots and poles count.

3. Material properties and thickness of stator and rotor laminations.

4. Air gap thickness.

5. Magnets grade.

6. Current density.

7. Slot fill factor.

8. Cogging torque. A summary of techniques used for reducing cogging torque:

  • Skewing stator stack or magnets
  • Using fractional slots per pole
  • Modulating drive current waveform
  • Optimizing the magnet pole arc or width
Brushless motor simulation

Brushless motor simulation 45KW 0.2mm lamination and 0.75mm airgap

 

motor simulation

Brushless motor simulation results

 

  • The final motor without the caps.
  • The motor with the caps and without the ball bearings.
  • I have also an YouTube video to present the 3D model.

Design stage Brushless motor60Kw


 

 

 

Brushless motor 50Kw

 

Close up view of the coils, magnets.

 

 

 

 

 

 

Brushless 40 poles 48 slotes 60kw

 

Air gap 0.75mm

 

 

 

 

 

 

Custom Magnets received  and tested by heating up to 120 Celsius to see if  any drop in magnetic field occurs.

Custom mamgnets brushless motor

Custom cut, N35UH grade, Phosphate coating magnets

Because the laser shop in Romania only had M330-50 grade, i was forced to use this material with higher losses for high RPM (frequency)

 

brushless motor design

Motor laminations  Grade M330-50 and other elements.

Drill to embed the screw in material.

Brusless motor construction

Drilling process

Brushless motor Rotor

Rotor assembly

Brushless motor homemade

Rotor with epoxy and kevlar to keep the magnets from flying from centrifugal force.

I used 14 strands of cooper 0.5mm in parallel.

48 poles brushless motor

Brushless motor winding

Winding the motor

 

 

brushless motor, car motor. Electric car brushless motor.

Motor finished, ready for testing.

brushless motor contruction, brushless motor water cooling

Motor Water Cooling

brushless motor homemade

Brusless motor ready for testing under load.

 

 

 

 

 

  1. Kukuh saworo says:

    Hi Iulian…

    Thats awesome…
    Do you need support?

  2. Kukuh saworo says:

    Hi Iulian…

    Thats awesome…
    Do you need support?

    Ball beraing, just buy …

    We can collect donation, if you want..

    • Berca Iulian says:

      I do not mind receiving a donation for buying an expensive Gauss-meter and a LCR meter,or other equipment to have further research

  3. Robert says:

    Salut Iulian,

    Am urmarit cu interes ceea ce faci si cred ca ar fi potrivit pentru proiectul meu, am o idee de pista cu karturi electrice si vreau un motor foarte eficient din punct de vedere randament-consum iar ceea ce prezinti tu aici cred ca se poate implementa pe un sasiu de kart cu axa motorului direct pe axa spate, ce zici ?

    Trimite-mi un email sau un mesaj pe facebook ca sa discutam mai multe detalii

    multumesc !

  4. Francois says:

    Hi,
    i want to made a motorbike for the TTX, and you motor is exactely what i imagine.
    can you tell me the weight off the 60kw motor?
    can you have more that 60kw, with the same motor with liquide cooler?
    do you sell it? if yes at witch prince?

    best regard François

  5. Kevin says:

    Very nice. I am working on a similar project but am having a difficult time finding a low volume source of electric (silicon) steel. Did you use this or regular sheet metal for you prototype? If you used electric steel, can you share where you sourced the material from? Thanks!

    • Berca Iulian says:

      Hello,

      I used electric silicon steel lamination. There is in Romania a factory that steel lamination.
      I took them from somebody else who was constructing large (MW size generators).
      So there is no place to buy like an online shop.

      Iulian

  6. Eduardo castellani says:

    Hello, congratulations on your project and make it available for everyone here.

    I want to make a prototype of an electric wheelchair for the poor of Brazil, with minimum prices, that is low cost and quality because everything here is carissimo.

    A hug and thanks

    Eduardo castellani

  7. Felipe Palomo says:

    Congrats!

    It’s a very nice design.

    How much it will weigh?!

    Did you ran it on a Dynamo to check specs?!

    Have you thought about using Full Ceramic Ball Bearings?!

    Cya!

  8. Max says:

    Hello iulian207,

    thanks for this huge amount of usefull informations.
    I also want to build a BLDC motor.

    You told “Multiple factors can have a huge difference in motor performance and efficiency:”
    Do you have any rules, formulars or scientific publications which deal about that?
    I’ve special ionterest in following points you mentioned:
    3. Material properties and thickness of stator and rotor laminations.
    6. Current density.
    7. Slot fill factor.
    8. Cogging torque. A summary of techniques used for reducing cogging torque:
    •Skewing stator stack or magnets
    •Using fractional slots per pole
    •Modulating drive current waveform
    •Optimizing the magnet pole arc or width

    Thanks for your help

    Max

  9. Felix says:

    Hi Iulian,
    I am just designing a 10kW motor for 100V and ca 30kV. In the Youtube I saw a calculator software for simulation the move/rotation and torque (not the FEMM). Can you let me know where to get it. I try to estimate best pole/mag combination. Another question regarding cooling. How do you thermally connect the core and the copper cooling tubes ? And… sorry..another one. You said you enforced with kevlar the magnets. Which strength did you use and how big does this make the airgap ? Sorry for so many question, but your work is very impressive and inspiring

  10. emerson says:

    what software you used to calculate this motor ?

  11. Nick Arsov says:

    Hi Iulian,
    I’m the designer and manufacturer of AUAV-Xx series flight controllers and the 80A FOC BLDC controller for multicopters. We’re interested in your BLDC high power motor and we want to buy one for development purposes. Please advice how much does it costs and can we pay you via PayPal?
    Best regards
    Nick Arsov
    Arsov RC Technology
    8 Konstantin Irecheck str., bl.1, ap.1
    4700 Smolyan, Bulgaria

  12. […] Many of us have tried our hand at the ol’ electric car conversion hack. Yank the engine, throw in an industrial DC or AC motor, and bob’s your uncle. Simple stuff. But if you can’t find just the right motor for your application… why not design and build your own brushless DC motor? […]

  13. stoyko says:

    Bravo for your success ! Greetings from Bulgaria ! http://www.ev-bg.com

  14. […] Many of us have tried our hand at the ol’ electric car conversion hack. Yank the engine, throw in an industrial DC or AC motor, and bob’s your uncle. Simple stuff. But if you can’t find just the right motor for your application… why not design and build your own brushless DC motor? […]

  15. […] Many of us have tried our hand at the ol’ electric car conversion hack. Yank the engine, throw in an industrial DC or AC motor, and bob’s your uncle. Simple stuff. But if you can’t find just the right motor for your application… why not design and build your own brushless DC motor? […]

  16. Chris says:

    Could this be adapted to a 3 phase AC version? / do you plan to do an AC design at some point? Many thanks.

  17. Rahul Jain says:

    Hi Iulian,

    This is awesome design. I am working on a BLDC motor project in my Final semester. can you please send me the CAD files for this motor to my email?? or can you tell me the thickness of stator and rotor laminations and total laminations used in rotor and stator??

    Thanks
    Rahul

  18. Jordan says:

    Hi Buddy, just an Idea I have but can’t realize it – missing work place. Think about the rotor space between the schaft and the magnets. Well, not place a modified by geometry an accumulating cells. What you win – a short wired reverse charging and a fast startup with less electrical losses. You will increase the weight of the DC unit but if implementig to a car this will be a good to keep weight on the wheel’s level. I know that my idea is not very efficient at the moment if using plump acc. Either if using Li- ones. But if we got more efficient acc cell, it will be a perfect solution to keep Acc and DC into one cage.

  19. Jordan says:

    and in addition to my last posting – if you revert the construction and put the magnets out and coling on the place of the rotor then placing a acc cells will looks more meaningful, right?

  20. Antonio AFCtin says:

    Buna seara,
    Sunt placut surprins de realizarile dvs.
    Motorul electric de 45KW prezentat de dvs are un raport greutate putere remarcabil 17Kg/60CP=0,284Kg per CP (cal putere).

    Daca proiectul dvs se va dovedi fiabil in exploatare va avea foarte multe utilizari.
    Aveti un grafic cuplu-turatie? Ma intereseaza sa stiu daca motorul dvs are cuplu bun si la turatie mica de ordinul 50rot/min.

    Sunteti dispus sa executati contracost un prototip de motor de 5CP 220V cu ax tubular pentru un proiect de masina unealta?

    Daca da, va rog contactati-ma la adresa de e-mail de mai sus

    Cu stima,

    Antonio

  21. jaynil says:

    my friend iulian
    i see your 45kw motor and i’m just shock. can you sand each and every measurement on my email id so i can built it for my college project? my id is [ pateljaynil007@gmail.com ]

  22. irieblue says:

    Take a look at the cutaway of a tesla motor. They appear to use flat wire in their windings. Per http://www.ecnmag.com/article/2011/03/integrate-flat-wire-inductors-high-frequency-high-current-designs flat wire provides more volume/density. I am interested in ypur design from a generator perspective. i.e. it is driven by water/wind/turbine. Does it work as a generator?

  23. eliechahoud says:

    how is the dimention of this motor laminations grade m330-50

  24. Tomas Mendes says:

    Amazing work. congratulations.

    I am working on a similar but much smaller motor project (260W). I would really like your help with calculations, winding, sizing, magnets ( the whole design thing).

    cheers
    Tomas Mendes

  25. Jeerawat says:

    How much for this project and how I can get more detail and price
    I want to make this one for my project please kindly let me know
    thank you

  26. nguyen van dong says:

    dear Iulian!
    i am a Phd student and i have a project underwater robot. but i am having trouble with dynamical system. i have power from accu : 90v, 500A. and i want to make a BLDC 45KW same your BLDC. can you give me some advice ?
    thanks you verry much!

  27. cam cat mar costA sa imi faci un motor ca acesta???
    astept un mail

  28. 797 30188Where else may just anyone get that kind of information in such a perfect way of writing? 822192

  29. Silvio Novais says:

    Please, where can I buy the parts to assemble this engine?

    I’m in Brazil

    novasi@bol.com.br

  30. Eliezer Costa says:

    I amazing you project. I need to construction one . Did you send me your project?

  31. Emile Fitzmaurice says:

    Dear Iulian

    Is it possible for me to get templates / drawings of the motor frame and laminations to build my own motor from your design

    I would also like to build the controller and install the pair in a car here

    Kindly advise

    Rgds Emile

  32. L. Lee says:

    Are these generators for sale?

  33. I would like to build a copy of this engine and then a motorcycle based on this engine.

    I have a well equipped CNC machine shop, if there is any way we can cooperate please let me know. Perhaps I can make some parts for you.

  34. mr do you have best invention from moter ,i ts relay good contraction idea .grate to grate thinking ,you can help us me .i m from inventor sir Lanka .smart self generating method i wont from you 45kw stator winding digram. will hope that you

  35. Hans Rodriguez says:

    Hi all

    I’m working in a EV conversion, and this motor fit my requirements, what is the motor price?

    Best regards

  36. thushara says:

    hello ,sir plz i wont to your winding diagram full photo,plz send me my e mail.

  37. Gabriel S. says:

    Salutare Iulian.

    As dori sa execut si eu un motor BLDC cu 9 poli si as avea nevoie de ceva informatii .
    Am achizitionat magneti neodinium 50x50x 25mm ,forta de atractie de 100 kgf.
    Poti sa ma ajuti cu un desen sau o simulare la statorul care vreau sa-l construiesc,motorul vreau sa fie OUTRUNNER.
    De unde pot sa fac rost de tabla de fero-siliciu .
    Locuiesc in Bucuresti.

    Multumesc!!!

    Mult succes in ceea ce faci!!!!

  38. Tim May says:

    I am interested in your motor
    Are you still making updates to this motor?
    Thank you for your work
    Tim May

  39. Nico Paulo says:

    Dear Julian,
    Could you sell me the complete design of this 45Kw engine?
    And how much I   Would charge to develop a 75Kw project?
    Best regards,
    Nico

  40. Robert says:

    hi i am deaf. i am very interested in electronic brushless motor.

  41. I am also interested to make a motor like this.

    Please let me know if you decide to sell plans.

  42. Jose Cordova says:

    I Designe and build a 60Kw BLDC motor 48 slots and 16 pols inruner
    wat motor drive are you using I cant fine one for this motor

  43. Jose Cordova says:

    can you contact me

  44. özcan says:

    Kaç pilinen döner ki bu

  45. Sujeet says:

    Can you also tell me the design of this 45kw bldc motor controller .please , I shell be thankfull. It can help me for my project to help nature.

  46. Adrian says:

    Salut,
    Felicitarile mele pentru realizarile deosebite, ma bucur sa vad ca acest material este scris de un conational. Am vazut ca sunt multi cei care doresc sa cumpere de la tine acest motor si chiar cred ca ar fi o idee foarte buna sa mai construiesti cateva bucati.

    Am vazut ca nu ai mentionat cat ar costa materialul + taierea laser pentru stator deoarece as fi interesat sa imi fac si eu propriul motor pe care sa il folosesc la diverse proiecte personale si as fi curios care ar fi posibilitatea sa iau un stator dintr-un motor deja existent, de exemplu de compresor frigorific sau altceva asemanator.
    As putea fara prea multe cunostinte sa calculez motorul pornind de la statorul pe care il gasesc intr-un motor deja existent ?
    Locuiesc in Bucuresti si sunt dispus sa platesc atat cat imi permite buzunarul daca gasesc un stator potrivit si ma ajuti cu calculele necesare.
    Keep up the good work.
    Multumesc

  47. BuzogányBenjámin says:

    Please send me the technic/CAD files so i can build that motor as well.
    buzoganybeni@gmail.com

  48. Jonathan Schmidt says:

    Do you have any test measured results about the

    Will you please post a drawing with dimensions or a CAD file of the metal parts?
    I would be happy to pay for the CAD file.

  49. Eduardo Ruiz says:

    Hi friends, it is very interesting the video that shows the generator of 45 kw, could be accessed the plans and places where to buy the materials and the construction manual.
    I’ll be very greatful.

  50. Franco Potito says:

    Instead of using permanent magnets can you use electro magnetic in the rotar?
    In your motor, how many electro magnetics are on at one time? Is it possible to have all on at the same time? Can you make me a custom motor to my specifications? I would like to show you how to make what I feel is the most effective motor

  51. vld kost says:

    hi…i have a pancake motor of lg washing machine and i have problem run it do you have a controller that fit for it is winding 30degree i have ae-bike motor controller but it is for 60/120 degree

  52. cesar says:

    hi , how do you calculate core? i mean the size of the core?