What is Brushless: Definition and 43 Discussions

A brushless DC electric motor (BLDC motor or BL motor), also known as an electronically commutated motor (ECM or EC motor) or synchronous DC motor, is a synchronous motor using a direct current (DC) electric power supply. It uses an electronic closed loop controller to switch DC currents to the motor windings producing magnetic fields which effectively rotate in space and which the permanent magnet rotor follows. The controller adjusts the phase and amplitude of the DC current pulses to control the speed and torque of the motor. This control system is an alternative to the mechanical commutator (brushes) used in many conventional electric motors.
The construction of a brushless motor system is typically similar to a permanent magnet synchronous motor (PMSM), but can also be a switched reluctance motor, or an induction (asynchronous) motor. They may also use neodymium magnets and be outrunners (the stator is surrounded by the rotor), inrunners (the rotor is surrounded by the stator), or axial (the rotor and stator are flat and parallel).The advantages of a brushless motor over brushed motors are high power-to-weight ratio, high speed, nearly instantaneous control of speed (rpm) and torque, high efficiency, and low maintenance. Brushless motors find applications in such places as computer peripherals (disk drives, printers), hand-held power tools, and vehicles ranging from model aircraft to automobiles. In modern washing machines, brushless DC motors have allowed replacement of rubber belts and gearboxes by a direct-drive design.

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  1. O

    How to wind a brushless motor (number of windings per stator)

    Hi folks, I'm searching for information/procedure and also calculations/equations on how to correctly wind a stator on a (general or DC 3-phase) brushless motor? I.e. how to wind a copper wire X number of times around the stators, and thus get the desired performance/force that is required...
  2. kolleamm

    I need a controller for this 25kW DC Brushless Motor

    Here is a motor I bought : https://www.alibaba.com/product-detail/55kg-thrust-MP120100-brushless-motor-kits_60816322811.html?spm=a2700.12243863.0.0.2ce83e5f3D0fu9 Can anyone recommend a controller I can use for it? There's many online but I'm unsure which to choose. The motor has 3 cables and...
  3. K

    Choosing the right ESC for a Brushless motor

    Hello everyone. I have a RC helicopter (WLtoys V912) that recently had a crash. The main board was damaged and replaced and I got it working again but there is a problem. The main brushless motor is not as powerful as before and I have to apply 75% throttle to keep hovering above the ground. It...
  4. S

    Homopolar, Brushless and Brushed DC Motors

    I've seen examples of each of these types of dc motors. What I haven't found is a dc motor that doesn't use pwm, commutators/brushes, or some sort of slip contact. Is there a such thing? If not, would there be a demand for such a motor?
  5. B

    I want to make brushless motor.

    Sir, I want to make a brushless motor out runner type. Body is 2.5 thick with 25 cm outer dia. It's weight is 25kg. Shaft of stator is 4cm in dia. How much watt is required for rotating this outer body at speed of 12000 rpms.
  6. D

    Difference between ESC and brushless motor controller?

    This is a 2 part question and I guess it applies to the brushed case as well. 1.What is the difference between an electronic speed controller (ESC) and a brushless motor controller show below: ESC: http://www.robotshop.com/en/lynxmotion-12a-multirotor-esc-1a-bec-with-connectors.html Brushless...
  7. D

    Energy from bike riding used to charge phones/laptops

    Hi, I've been thinking up a project on harnessing the kinetic energy to use for charging or powering small deviecs around the house firstly my laptop and smart phone. I have a basic idea of what I'm going to use and have some of the things needed. My idea was to use a small brushless or maybe...
  8. J

    Brushless gimbal motors vs servo?

    anybody know anything about stabilization systems? I posted the question "Servo vs. Stepper motor for stabilization" before, and I eventually learned that stepper motor draw power while holding position, which servos do not, so I was fixated on servos for a while. Then I started realizing how...
  9. Madhusha

    Difference Between 120 & 180 Degree Pole Arc Brushless DC Motor

    Guys Can you give me what is the difference between construction in 120 degrees pole arc and 180 degrees pole arc brushless DC motor with trapezoidal bldcm?
  10. S

    Can a 555 timer be used to control a brushless DC motor with the help of an IC?

    I have seen a link in this forum http://ww1.microchip.com/downloads/en/DeviceDoc/22263A.pdf that denotes an IC to control a brushless DC motor. How to connect it with a 555 timer? Can anyone help me with the entire circuit diagram? Thanks in advance.
  11. R

    DC brushless motor vs. AC motor

    I noticed that common technology such as brushless DC motors use AC to drive them. What exactly makes DC brushless motors different from AC motors if they both ultimately take in AC? Why even refer to DC brushless motors as DC motors if they're not even driven by DC? I understand the source is a...
  12. V

    Why Do DC Brushless Motors Need Hall/EMF Sensors?

    I understand the basic gist of the whole DC brushless motor, but I don't understand why there needs to be a sensor. Why can't the controller just alternate between phases at a constant rate? What I mean is that if there are a fixed number of ways the coils can be charged, why not just alternate...
  13. T

    Brushless DC Motor torque calculations?

    Hi there guys and girls I am new to this forum , so please have mercy. I am searching for equations to calculate the torque of a 3 phase brushless dc motor. Any info or textbooks on this maybe? Thanks Tommie Prinsloo
  14. I

    Calculating Brushless Motor's Torque

    Hello, I was wondering if anyone knows about calculating the torque of a brush less motor (preferably an out-runner). Is there a way to get the torque based on resistance, number of turns, and number of poles? Thank you, Denis
  15. B

    Brushless DC Rotor Position Question

    Hi. I am curious about ways to sense the position of a rotor in a BLDC motor. I am familiar with hall sensors and back emf but am wondering if there are other ways to find the position of a rotor maybe more accurately. I had an idea about using a laser and a photoresistor around the...
  16. N

    Electronic Speed Controls & Brushless Motors

    With an ESC powering a brushless motor, does the ESC get power feedback? Sorry I don't know the terminology, so I'll ask it a couple of ways. The power from the esc runs through a big length of wire windings. I get this isn't a short circuit since enough of the power is turn into heat, does the...
  17. N

    Dc brushless motor in locomotive is it possible?

    hi guys homework r u? I have zis question about locomotives Is it possible to drive locomotive by brushless dc traction motor?
  18. V

    The difference of Back EMF waveform shape of BLDC and brushless PM generator

    I am a bit confuse on the back EMF waveform shape of the brushless permanent magnet machine. As I know brushless DC permanent magnet motor has a trapezoidal shape back EMF waveform. If I use this motor as a generator, do I still get the same waveform shape or I will get a sinusoidal waveform?
  19. D

    Questions concerning about brushless dc motor

    questions concerning about the brushless dc motor in a brushless dc motor,does the power given by a battery move in and out throughout the electric current of the magnetic wire? I have the magnetic wires both parallel to each other and placed at the negative and positive terminal of the...
  20. T

    MATLAB How to simulate a Brushless dc motor drive in MATLAB/SIMULINK? thanks.

    I have uploaded the journals which related to the brushless dc motor. I encountered the problems as i don't know how to simulate the voltage source inverter of the Brushless dc motor system (the generation of inverter line to line voltages) and the hysteresis current block. i really need help...
  21. M

    Direction of rotation, brushless or brushed DC motor

    I still don't understand why these types of motors tend to spin in one direction or another. In theory the direction of spin should be random since when the north pole of the rotor magnet is lined up with the north pole of the electromagnet in the stator the rotor could be repelled clockwise or...
  22. B

    Understanding Brushless Motors: A Comprehensive Guide

    So here is the thing. I was searching the internet for information about brushless motors. Everywhere I went, they had mixed statements about it. Long threads about which is it, is it controlled by AC or DC or what have you. I am interested in book, that is covering this subject in depth...
  23. F

    Automotive Designing a brushless AC motor for Formula Student

    I am on a Formula Student team and we have decided to design our own brushless AC motor. Our main issue is how we will cool the motor, since we want to keep weight down while also increasing power output. We will be making the rotor from forged Titanium (Ti6Al4V) and the housing from forged...
  24. B

    What is needed to drive brushless motor?

    http://homepages.enterprise.net/jayjay/cdrom_motors.htm So this is modified brushless motor. It says that it uses jeti06 ESC. But frankly I am not ready to sneeze 25€ for a ESC. How do you drive this in principle? You send pulses into those 3 windings, one after another...
  25. Low-Q

    Is it possible to create a brushless DC motor that runs solely on DC current?

    Hi, I use brushless DC motors for my hobby things (planes, cars, helicopters). These motors have a special ESC which outputs a 3-phase AC current to the motor. These motors have stationary coils, and a rotary magnet array. The motors have an incredible torque for the size. I have, however...
  26. M

    Welcome Engineer Designing a 30 W Brushless DC Motor

    Hi to everyone :-) I'm new to this forum. I'm an engineer working in a core field. I need to design brush less dc motor of 30 W power, Inout voltage-13.5 V. I'm struck in winding design . Could anyone help?
  27. J

    Insulated brushless motor windings

    Hi, I've never done Physics before (bad choice I know :P) so forgive the question if it seems a bit noob. Do the windings in a brushless motor have to physically be in contact with the magnets in the stator? That is, can the windings be insulated? Thanks Jamie
  28. R

    Brushless DC Motor Investigation

    Hey guys, I'm new to this site, and am a university student studying Electrical and Electronics engineering. I just completed a design project controlling a BLDC motor (pretty low powered at 60V, and giving output rpm of about 6000rpm). Now I had an idea where instead of using a single BLDCM...
  29. I

    Speed/torque curves for brushless DC motor

    Hi everyone. I came across this site yesterday during some targeted Googling and thought I'd give it a shot. I have a basic question about speed/torque curves for brushless DC motors. I would like to compute a speed/torque curve for a small three-phase brushless DC motor that I have. It...
  30. H

    Make a Brushless DC Motor this way?

    I know the magnetic field makes a circle around a wire with current flowing through it. So I wondered if a motor could be made in the following way. Take a round plastic sleeve with an inner diameter slightly more than the wire. Glue 4 magnets on the sleeve, such that they form a circular...
  31. J

    Slowing down a brushless DC motor in a VCR

    I'm trying to modify a VCR so that the big drum that scans the tape spins slower (for an art project...). It's a brushless DC motor that uses a special VCR-specific IC to control it, I believe. The chip is a sanyo LB11885 (http://www.semiconductor-sanyo.com/ds_e/EN7884A_d.pdf" datasheet). VCR...
  32. S

    How Do I Build a Controller for a Brushless HDD Motor for an RC Car Experiment?

    Hello! i need help with a brushless motor from a HDD. I have very little understanding of how they work, i want to create a controller for this motor, something like a throttle system for an rc car. this is an experiement for me, I am sure the motor is not ideal for RC cars but i want to...
  33. K

    How are BLAC motors wound and what makes them different from BLDC motors?

    Hello, I've recently read a couple of things about brushless motors that have spurred quite a few questions. Googling has solved some of them, but I'm hoping that you can help with the rest :smile: Apparently there are two types of permanent magnet brushless motors - DC and AC. This is...
  34. A

    DC Brushless Motor Rotor Steps: 4 Poles North/South?

    Hello Forum, I have a 3 phases DC brushless motor from a Hard Disk Drive, when energize one coil and turning by hand the rotor i can feel 4 steps per rotation, is this means that this motor has 4 poles of north and south? Thank you in advance, Anita
  35. R

    Which DC Motor Is More Powerful: Brushed or Brushless?

    Dear Sirs/Mdms, I would like to find out how different is a brushed vs brushless dc motor in terms of size, weight and power . I can find articles on the net regarding some comparisons between the 2 types. For example, a brushed is less efficient than a brushless motor. But i cannot...
  36. L

    Steam driven brushless DC generator - would this idea work?

    Hi fellow thinkers. I need constuctive criticism on the following:- Imagine a tube circling around into a closed loop - like a hoop. Inside the hoop is a ring of connected bar magnets all facing the same way. Pressurized steam is fed into the hoop - and exited in such a way as to spin the...
  37. A

    Identifying Phases & Common in a 3-Phase Brushless DC Motor

    Hello Forum , i have a spindle motor from a Hard disk , it's a 3 phases DC brushless motor . This motor has 4 wires , 3 phases and 1 common , how i can know the phases and the common ? Thanks in advance. Anita
  38. C

    Where to Get Small Brushless DC Motors

    Hopefully this is the appropriate forum for this sort of question, but I was wondering if any of you might know where I could buy small brushless DC motors online. I've been Googling around for a while, but most of the ones that I found are too large and expensive for what I need, as they're...
  39. K

    Brushless DC Motors suitable for Underwater?

    Hi people, im new to this forum. I'm currently working on a underwater ROV for my school project. We did a experiment recently on the performance of our ROV. We met up with some problems on the motor & the propeller for the thrusting. The motor stalls just after 5secs. So I am thinking is...
  40. E

    TORQUE calculations for Brushless dc motor.

    OK hey guys, I am building an electric go kart for a final project, and I'm just trying to get my initial justifications correct, with respect to the classical physics involved. SPECS: i was the car to be able to reach 60km/h, The total weight of the car will be approx 200kgs. the size...
  41. dink

    What Is the Best Textbook for Comprehensive Learning About Brushless DC Motors?

    I'm looking for a textbook that has an in depth coverage of brushless DC motor physics as well as control theory. -indepth mathematical approach as well as conceptual theory -controller schemes and design fundementals -mathematical study of induced currents on the stator/rotor, and what this...
  42. B

    Understanding BLDC Motor Control: Position, Speed, and Current

    Hi guys, I'm developing a BLDC motor controller with load. I've bought a Maxon E40 motor . But some things i can't figure out: I want to control position, speed and current (torque). I use PID controller to do it. In the closed loop system the output of the speed controller should be input...