What is Bldc: Definition and 29 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. V

    BLDC Motor - Finding out how many Pairs of Poles and the difference with PMSM

    Hello Community, i have BLDC motor with General parameters are 3 Phase motor with 4 Poles, 36V, 7.3A rated current, 4000RPM rated speed. you can check datasheet on link below The first question is how many Pair of Poles does this motor have? 2 or 4? For example the motor bellow...
  2. V

    STM32 BLDC driver advanced configuration

    Hello Community, i have a X-NUCLEO-IHM08M1 BLDC driver which will be controlled by a HMI (generic industrial product) combined with Nucleo nucleo-f401re. I developed the HMI part and currently i work on communication between the HMI and the Nucleo. I would appreciate any help to configure the...
  3. V

    Handle Peak Inrush Current of a BLDC Motor to protect the Power Supply

    I have to use a BLDC motor combined with a BLDC motor driver (X-NUCLEO-IHM08M1) The motor has a rated current of 7.3A. So i am planning to use a 36VDC 13.9A power supply (SMPS). The problem is that the PS that i want to use has a "HICCUP mode" for overload protection and not a "constant current...
  4. E

    How do motors on gimbals work? (2-axis camera mount application)

    Hello everyone, I am trying to build a 2-axis camera gimbal, which will control yaw and pitch. I have bought sensorless BLDC motors (GB280870KV) which I drive using SPWM. For knowing the camera orientation, I am using IMU sensors (accelerometer, gyroscope, and magnetometer) integrated on the...
  5. M

    Calculating KV for BLDC Motor Re-Winding with Different Wire Materials

    I'm looking at the formulas for re-winding BLDC motors to change the motor constants KV (max rpm/v) and KT. I've read that the formula is as follows (assuming wye termination): Original Turns Per Tooth # * Original KV = New Turns Per Tooth * New KV which can be rearranged: (Original Turns...
  6. D

    BLDC motor as generator to power eddy current brakes

    Hi everyone - here's a concept that I'd like a few opinions on: As part of a project, I'm looking at using a brushless DC motor mounted on a high-speed vehicle as a generator. Once the vehicle hits its top speed, the batteries should disconnect from the motor and the vehicle's own velocity will...
  7. A

    How to find the torque constant of BLDC motor?

    Hello Friends, I have used in-wheel BLDC motor for my experiment. In this type of motor BLDC motor inbuilt on wheel. This wheel is a part of electric scooter. I wated to find the value of torque constant and back emf constant. Also how to measure torque for a selected current. Please help me...
  8. P

    3 phase motor net magnetic field

    I am trying to understand the basics of bldc motor. My question is if i am driving the 3 phase motor with sinusoidal waveform. The magnetic field is produced for each phase or it will add together to generate net magnetic field? How to get the net magnetic field.
  9. yavorh

    BLDC: Required voltage to get set rpm at given amps

    Hey guys! So I'm trying to do this pretty wide diameter in-runner engine, where the rotor is hollow (essentially trying to make a short tube within a short tube :D). After checking out the details between the different types of electric motors (and realizing that I can barely find any...
  10. F

    Exploring BLDC Motor Windings & Efficiency

    I learned that brushless DC motor windings have an algorithm for winding depending on several variables... When I google image search BLDC stator, I expect to see this : But I see a lot more of this : Is this second one still a brushless DC? If so, do they just lose efficiency by winding...
  11. F

    How Do You Properly Attach Magnets and Bearings in a BLDC Motor Rotor Design?

    Trying to design a motor for a learning project. Finished the math but having a lot of trouble with design questions. Can anyone give me some insight. For the rotor in this picture there is a ring magnet. Is the magnet glued on? I think it is glued onto electrical steel. 2nd question, on the...
  12. P

    Maximizing Current Output of BLDC Generator for Power Generation Project

    I'm using the following BLDC motor as part of a project to generate power: http://www.rcdude.com/Cobra-C-3520-18-Brushless-Motor-p/c-3520-18.htm I'm able to spin this motor to about 3000 RPMS which gives me about 5 Volts. This is to be expected given that the motor is rated at 550 KVs. I'm...
  13. mr.93

    Maxwell 2d (ANSYS): Bldc motor simulation

    Hi all I have few questions in bldc motor simulation in maxwell 2d: - I need help in loss calculation,I exported a bldc motor in rmxprt to maxwell 2d after entering core properties and w/kg data in 50hz,in 2d checked stator and rotor in set core loss and checked (consider core loss effect on...
  14. S

    Selecting a BLDC Motor for an Electric Tricycle | 400W, 48V, 0-4m/s in 20s

    We are designing an electric tricycle having rear wheel drive(26 inches wheel dia).It will weigh around 400kgs including drivers. There are constraints for motor output power(max 400 watts) and voltage(max 48v). What are the calculations to be done for the selection of motor. The desired speed...
  15. S

    Gear Ratio & Voltage/Current Calculation for 24V 1500rpm BLDC Motor on a Tricycle

    I have a 24V, 1500rpm bldc motor.The power output will be around 400W. We are using it to electrically drive a tricycle. How can I calculate the gear ratio to decrease the rpm and increase the torque? The transmission system includes an intermediate shaft with 22 teeth sprocket and 44 teeth...
  16. T

    Calculating Phase Resistance for BLDC Motor: What Factors Should I Consider?

    Hello, I have a three phase BLDC motor and I am trying to figure out its phase resistance. I have acquired the three-phase voltages and three-phase line currents of this motor. The voltage is in trapezoidal form whereas the current is in rectangular form My question is: how can I find out the...
  17. Dostetres

    Multiple BLDC per shaft for marine propulsion

    New to the forum, and can't find this info or examples on the web. I'm interested in the possibility of coupling multiple DC brushless motors to a single drive shaft for main propulsion on a 45-50', twin screw boat. Lots of sail boat examples are given, but my interest is in a power...
  18. U

    Can BLDC Technology Solve Voltage Fluctuation Issues for Domestic Water Pumps?

    Hi there, I have spent quite some time on PF as an unregistered user reading through various stuff and have learned a lot. Just registered now to seek help on something that's been bothering me a lot and to which I haven't managed to find a solution yet. Please let me know if this is not the...
  19. J

    How Do Rotor and Stator Pole Numbers Affect BLDC Motor Efficiency?

    hi, There is one thing that I do not understand and nor do I find any direct explanations for it. Is there any relationship between no of rotor poles and no of stator poles in BLDC motor (or PM Synchronous Motor)? I have read somewhere there doesn't have to be. I can imagine if no of poles are...
  20. T

    Calculation of torque power for BLDC

    i am building a solar electric bicycle for my final year project,in our project we are using solar panel to convert solar energy into electric energy and that energy will be stored in the battery. now we require brush-less DC motor to start the bicycle. so which torque equation should i use to...
  21. Z

    New type of electric motor (true BLDC)

    [url]K-yyJF-kTMw[/youtube]I'm not 100% sure it works because I haven't built a physical prototype yet. Though, the only problem that I see at the moment is the low power density potential and the low efficiency. Meaning that it WILL NOT REPLACE conventional brushed or BL motors. I would really...
  22. B

    Modelling/Simulation of a Linear BLDC motor

    Hi, I'm trying to implement a complete model of ha Faulhaber Linear BLDC motor with the purpose of derriving a controller suitable for a microcontroller ouputing a PWM voltage. The motor is supposed to move a given load to follow a reference signal. Accordingly to...
  23. D

    Exploring the Function of a Capacitor in BLDC Drivers

    Hello, I feel like I know the answer to my question, I am just having a lot of difficulty putting it into words. The questions is the following: I have a BLDC driver chip that has a pinout called PBAT and a pinout called VCC. The PBAT is tied to 12V and the VCC is tied to a 2.2uF cap...
  24. 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?
  25. C

    Interpreting BLDC motor spec sheet

    Hi everyone, first time poster! Im having trouble reading the spec sheet attached and want to confirm the values I am using for calculation of Tm and Te. The 3 phase wye BLDC motor spec sheet lists 1. Terminal Resistance = R2ph = 0.06 Ω So this is Rphase and not R(line to line)...
  26. M

    BLDC Motor - Operation with Phase Loss

    Hi, I am using a 3 phase BLDC Motor. The scenario is, "When anyone of the phases to the BLDC motor fails, the hardware will disable the particular phase. My software should stop firing that phase." Thereby the motor should run with only 2 phases. Is this practically possible to run a 3...
  27. M

    Control BLDC Motor with 555 Timer: Tutorial & Schematics

    I have read that it is possible to control a Brushless DC Motor With A 555 Timer, However I Do Not Know How To Accomplish This, And Have Been Unable To Find Any Schematics For This. Could Someone Please Explain To Me How To Do This And Provide Images Or Schematics. Also, If It Is Not Possible To...
  28. T

    How Can I Design a BLDC Motor with 300W Power, 24V Voltage, and 40 Nm Torque?

    Hi, could someone guide me through the steps of how I would go about designing a bldc motor, knowing only the following requirements; a) Power 300W b) voltage 24V c) Torque 40 Nm d) RPM 180 e) Max external dia = 254mm f) Max length = 90 mm So now I need to know; 1) How many poles...
  29. T

    Addressing Load Performance in Sensored BLDC Motors

    Hi, I am using Sensored BLDC motors for some robotic movements. I am driving my motors using motor drivers. I am using ball screw mechanism for lifting a pedal up and down. On the pedal, there will be always a very high load, placed on it. Now, my motor can lift up the pedal with my desired...