Questions tagged [brushless-dc-motor]

A brushless DC electric motor is a DC motor type that uses an electronic inverter/switching circuit to energize the motor coils in a sequence (based on the detected rotor position) in order to rotate the motor.

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How are current and voltage related to torque and speed of a brushless motor?

I know that electric vehicles have different performances depending on battery and motor, but it's not clear how electrical and mechanical units are related. Can anybody please help? Will a 100V ...
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6answers
63k views

How to drive brushless motor with Arduino?

Is it possible to drive a brushless motor directly with Arduino? Or should I revert on controlling a brushless motor ESC with PWM pulses?
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2answers
56k views

Difference between Brushless Motor and Stepper Motor

I think I understand the operating principles of a brushless motor and a stepper motor, but I'm a little confused about the difference. Is a brushless DC motor a very basic stepper motor? With ...
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7answers
6k views

Why do brushless motors have a kv rating?

I am wondering why brushless motors, such as ones used for quadrotors, have a kv rating, which supposedly means RPM per voltage across the motor. So a 2300 kv motor spins at 2300 rpm if "1 volt is ...
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2answers
2k views

Why do BLDC motor (1 kW) controllers have so many MOSFETs?

I have a 1 kW three-phase BLDC motor from China, and I was developing the controller myself. At 48 Vdc, the maximum current should be about 25 Amps and a peak current of 50 Amps for short durations. ...
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3answers
32k views

Control differences between ac induction motor and brushless dc motor?

I have a fairly solid background in industrial AC motor control (soft starters, VFDs, etc.) but something that I'm certainly NOT well versed in is brushless DC motors... the type found in every hard ...
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1answer
4k views

How to use an ESC

I'm new to RC related modules. Today I got my Hobbywing's Skywalker 20A brushless esc. Manual is here. I also have a brushless outrunner motor (HL3512) I don't ...
9
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1answer
555 views

Need help understanding and interpreting IGBT datasheets

When it comes to motor control, I understand that we have the option of using discrete MOSFETs or IGBTs. Also, there are some products in the market where 6 IGBTs are placed in one single package, ...
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2answers
543 views

Why does my BLDC motor change behavior at high speed?

Background I've recorded torque vs speed performance of a small sub 50 gram hobby BLDC motor, the KDE 2304XF-2350. I power the motor at different fixed voltages to the ESC (electronic commutator) ...
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2answers
1k views

Blind Driving a Brushless DC Motor BLDC

I'm looking at making a BLDC controller with an MCU, and have be reading through the atmel guide AVR444 which steps through a design and software needed for a sensorless back-emf timing controlled ...
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3answers
15k views

Wind turbine generator: brushed or brushless DC motor?

I am trying to use a DC motor as a generator for a wind turbine but then there are two possibilities for the DC motor which are brushed and brushless. Which one is more efficient to use? I know that ...
8
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1answer
239 views

Inferring back emf from oscilloscope

I have this stepper motor with unknown back EMF / RPM. There are 200 steps/rev (i.e. 1.8deg step angle), and 8mH "phase inductance", but I'm not sure if that's enough to calculate back EMF. I hooked ...
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4answers
4k views

Why Have Non-Zero Timing on a BLDC?

I've heard you can go faster in one direction if you adjust the timing, but do not understand why? I have a sensored bldc motor with a 30deg shift of the hall-effect sensors, tried going forward (CCW ...
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4answers
7k views

Brushless motor specs to maximize stall torque

I'm interested in a brushless motor having a high stall torque (not much in RPM). What specifications of a BL motor would give a fair indication of its stall torque, provided that voltage is fixed ( ...
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6answers
1k views

What's the output of a record cartridge playing an out-of-speed record

I'm very interested in vinyl records and analog music, and the belt of my turntable got loose. Upon such situation it piqued my curiosity, what is the output signal at the end of the arm cartridge ...
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3answers
41k views

What determines the speed of a brushless DC motor

When driving a brushless DC motor, which parameters control the speed. Is it the current in the windings, the voltage, or both? What determines the maximum speed? If you drive the windings with PWM,...
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4answers
63k views

Understanding motor constants Kt and Kemf for comparing brushless DC motors

So for a practical definition, the torque constant Kt specifies how many Nm of torque you'll get from the motor at a certain current? Is a bigger Kt always better? I am more confused about the ...
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4answers
2k views

Why do we need brushed motors?

Looks like brushless motors are more convenient - no brushes means no maintenance required. For example, power tools manufacturers often cite that graphite brushes need to be replaced every 50 hours ...
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4answers
11k views

Can you run a BLDC motor backwards without damage?

Can you run a BLDC motor backwards without damage? Is it OK to drive a model airplane BLDC engine backwards while landing, so it gets a little "reverse thrust" and come to a stop a little quicker on ...
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2answers
6k views

Controlling small brushless dc motors?

I'm designing an ESC with a small microcontroller running at 3.3V. The BLDC motors I have chosen are extremely small, and run best at 3.7V. I have the power supply for both of these (3.7V is VBATT, 3....
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2answers
11k views

Controlling a Brushless ESC with Arduino

I read this is possible here: How to drive brushless motor with Arduino? I'm just getting started with Arduino and electronics in general, can anyone recommend a tutorial or guide that could serve ...
5
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2answers
6k views

What is the use of PWM over brushless control

I just saw this question How do I eliminate PWM noise when driving a fan? but cannot think of the reason why is doing PWM over brush-less control useful. I am assuming people are trying to control ...
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3answers
3k views

Driver failure when driving IRF3710 mosfet using IR2101 driver

I've made a driver circuit using IR2101 driver and a fairly large IRF3710 mosfet. The circuit works up to a certain current through the mosfet but then the driver mysteriously fails and pulls both ...
5
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1answer
707 views

High Side and Low Side MOSFET Driver… with low supply voltage

I need to drive a pair of N channel MOSFETs, one on the high side of the load and one on the low side of a load. Most ICs I can find for this application require 10V+ supply voltage to get the the ...
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2answers
8k views

Which voltage uses the “Kv” parameter in a BLDC (Brushless DC) motor?

According to the definition of a BLDC by Wikipedia: \$K_V\$ is the motor velocity constant, measured in RPM per Volt (not to be confused with "kV," the abbreviation for "kilovolt")[6]. The \$K_V\$...
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1answer
3k views

Stopping a brushless DC motor in a specific position

I have a BLDC motor on an autopiloted model airplane, running with an ordinary PWM-controlled ESC. I have a feature I'd like to add which the ESC I have doesn't support, so I either want to find one ...
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2answers
1k views

Need help with the BLDC drive inverter circuit problem

I am building a BLDC drive circuit for a 24V/60W BLDC motor. I chose SI4564DY(P+N) and FAN3278 to realize it as shown below (I only include A+ and A-, B and C are exactly the same). The FB indicated ...
5
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1answer
2k views

Magnetic field strength and bldc rotor

As a background to this project, I have taken an off the shelf bldc stator and incorporated it into a small pump, and then built my own rotor using discrete neodymium magnets. At first, everything ...
5
votes
1answer
633 views

What is this part? PN:R19F 2E

Mystery Encoder I think this is some sort of rotary encoder, but it doesn't seem to act like one (no quadrature output from the pins). Tests I've run: 5V input in each pin, monitoring the other ...
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2answers
3k views

How do you read newer HDD motors (DC/Brushless) into arduino? (like stepper motors)

We had a version of the HDDJ working with an arduino reading an old stepper motor (with 4 wires), then sending serial data to processing, using a midi library, and midiox + midiyoke. Having trouble ...
4
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2answers
740 views

BLDC Motor Constants: Why is my Kt and Ke different?

I'm new to working with motors. Reading up on BLDC theory, it is repeatedly said that in SI units, the Ke and Kt will be numerically equal. I downloaded the motor spec excel sheet of the T1101 motor ...
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2answers
6k views

Cannibalizing a printer, how to figure out what some of the parts are/do

My son an I are attempting to cannibalize a printer a HP LaserJet 1300. It used to work and print, but it was low on toner and the company we got it from replaced it instead of buying new toner. So, ...
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2answers
1k views

Electronic Speed Control Concepts

I am a programmer who has never worked with electronics before. I am learning the concepts and hoping to build a quadcopter, with the control software entirely written by me. Motor control seems to be ...
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2answers
4k views

What do the green and yellow wires in a BLDC fan do?

I rescued a box of brand new 'Nidec UltraFlo V60E12BS1A7-09A032 12VDC 2.45A' fans from being thrown away and of course I haven't got the datasheet for them. The closest matching datasheet is here: ...
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1answer
2k views

Non-regenerative braking on a PMSM/BLDC motor

Problem I have been working on drives for a while, but one problem that I never seem to be able to really get around is the regeneration that occurs when our PID loop commands a lower speed/torque ...
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1answer
6k views

Explanation of Lq, Ld and how it relates to motor inductance

I'm pretty much a novice to motor controls, but I was wondering if any of you could explain the concept of d-axis and q-axis inductance and how it relates to the inductance L that is usually specified ...
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2answers
3k views

Reverse-engineering a brushless ESC, could someone help me understand the circuit

So I'm in the process of trying to reverse-engineer a hobby brushless ESC. Above is the schematic for a single half-bridge drive circuit. VIN is 11.1V D1 is an unidentified diode; all that I've ...
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1answer
541 views

Total current used by a brushless DC motor

Is it correct to say that 'the current' drawn by a BLDC motor is the same as the current from any single phase at a given time (assuming they are all balanced/equal in magnitude)? I came across this ...
4
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1answer
750 views

Park/Clarke Transform and Power

I'm looking to determine the electrical power input to a 3-phase BLDC motor, driven by TI's DRV8305 motor controller. I can't use the DC power flowing into the system because I'm trying to capture the ...
4
votes
1answer
427 views

How to interpret the equation \$e=K_e.\omega_m\$ in a BLDC context?

After researching a while on the subject, I noticed that several sources state that the back-emf constant of a BLDC motor satisfies the following equation: $$ e = K_e.\omega_m $$ where: \$e\$ - ...
4
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1answer
378 views

How to connect a large exisiting code (some simulator) to the AVR Studio Simulator?

Context I am working on a brushless DC motor controller project. And I would like to verify that the interrupt timings make sense in simulation before downloading my code to the board. Challenge ...
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1answer
2k views

BLDC Regenrative ESC and LiPo [closed]

I am currently working on a project where I want to implement a Brushless dc motor (like the Turnigy C2226 - 1800kv) to run in-hub of an RC car. I need this entire project to be as lightweight as ...
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3answers
2k views

What does changing the throttle to a BLDC ESC actually do?

Background: I understand how the standard 50 Hz PWM protocol for hobby electronics works: varying the on-time from about 0.5 ms to 2.5 ms will throttle an actuator from roughly 0% to 100% thanks to ...
3
votes
1answer
2k views

Motor current consumption and power do not match

I am working on a design and need to calculate the energy consumption of this motor: https://www.maxonmotor.com/medias/sys_master/root/8825428410398/17-EN-256.pdf. (Part No. 339252) The ...
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3answers
183 views

bldc motor, esc and battery draw, nominal vs peak

I want to better understand how Electronic Speed Controllers (ESC) work for BLDC motors. Specifically, I am trying to understand battery current draw. Question 1: When an ESC is rated at 200 amps ...
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3answers
12k views

Can ANY DC brushless motor be used as a generator?

Question is pretty much in the title. I know it's definitely possible to use certain DC brushless motor as a generator, but is it always the case? Thanks a lot in advance.
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1answer
3k views

BLDC PWM frequency

I am driving a BLDC motor using a 6-step commutation table at a 40kHz PWM frequency and I am at a loss choosing the optimal one. I understand that the max frequency depends on the motor's R/L ratio ...
3
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3answers
1k views

Higher KV means lower torque for DC motors?

I'm in the process of trying to build an electric skateboard. On the websites I visited I read that torque and KV are inversely proportional which does seem counter intuitive. So I'm wondering why ...
3
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3answers
4k views

why the supply voltage of dc motor decreases when the motor load increases?

When I plot the supply voltage of a one-cell LiPo battery during the working period, I found that the supply voltage would drop dramatically when the motor is commanded to speed up. I think this is ...
3
votes
1answer
3k views

How to identify a BLDC motor from a brushed DC motor?

I got 2 dc motors from a broken cheap RC helicopter. How can I Identify what type of motor it is? It has 3 terminals, but only 2 where used. It takes around 2-3 Amps of current at 3.5 V. Each trace in ...