An electrical actuator converting electrical energy into rotational motion.
17
votes
6answers
33k views
What is a “digital” motor?
Dyson keep going on about their new "digital" motor. What is a digital motor? How can a motor be digital, it is inherently analog? Is it just marketing doublespeak?
16
votes
4answers
1k views
Why Tesla car use AC motor instead of DC one?
I just watch this mega factory and wonder why they use AC motor (exact time here) which require the power inveter, instead of DC which more direct from they DC battery. Introducing inveter mean more ...
15
votes
10answers
3k views
I'd like to learn how to make my own USB gadgets
I've been writing Linux character device drivers for other people's stuff for some time. I'd like to find a new hobby and the thought of making my own USB gizmos seems really neat.
I would be ...
14
votes
6answers
4k views
How do I physically work with a hobby motor?
How do I incorporate a hobby-style motor into a project, physically. How do I mount it and connect a wheel to it? (Assume that I have a working H-bridge or even switches, and am not concerned about ...
14
votes
3answers
479 views
In a DC motor, is there one commutation point that is optimal in all respects?
This recent question got me thinking about commutation timing, and why advancing it can be desirable. However, I wanted to consider more deeply the underlying phenomena, and I'm pretty sure my ...
13
votes
6answers
20k views
How to drive 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?
11
votes
4answers
2k views
How can I sense the motor's current?
I need to drive a DC motor @ 24V, 6A with a MOSFET. How can I sense the current that the motor is drawing with a microcontroller? I have to know when the motor is stalled.
10
votes
2answers
4k views
Is it possible to drive a stepper motor greater than 1000 rpm?
How could I achieve this?
What are the stepper motor facts
and principless that I have to
keep in mind to design a circuit
to achive this goal?
Are there any readymade/open source
alternatives ...
10
votes
1answer
934 views
How can I implement regenerative braking of a DC motor?
I know that many electric cars are able to convert the momentum of the car into stored energy in batteries, rather than convert it to useless heat at the brake pads. How does this work? How can I ...
10
votes
2answers
838 views
How is this design for a basic PCB pick and place?
I have zero experience with any serious mechanical design, but out of necessity and curiosity, I'm attempting to build a pick and place machine (for my hobby projects as well as low-volume PCB ...
9
votes
3answers
4k views
9
votes
4answers
312 views
Methods to accurately move an object across a 2-D plane
This is the opposite/complement of my previous question, which concerned measuring the precise position of an object as it is moved/drawn by someone over a short duration. Assuming I use one of ...
8
votes
3answers
484 views
shooting object by using a DC motor
This is not directly electrical, but I am working on making a real life version of a coin block from Mario. Basically I use an LDR and to detect if someone punches the block and then use a transistor ...
8
votes
5answers
7k views
Very Slow Electric Motor
A customer has asked:
I want to slow down a small hobby
sized DC motor to a user variable
range that runs from slow to zero
RPM. I would simply use a wall wart
for a power supply and a ...
8
votes
4answers
467 views
Precise motor positioning
I am trying to make a device that uses several motors all with an arrow fixed on top that has 8 fixed positions (N,NE,E,SE,S,SW,W,NW). I am trying to avoid servos and steppers because of the price, so ...
8
votes
4answers
682 views
Why use DC motors for driving elevators?
This New York Times article says that on November 14, 2007 Consolidated Edison Company was going to end supplying direct current to the remaining several buildings that used those to run elevators.
I ...
8
votes
3answers
10k views
How to drive a MOSFET with an optocoupler?
What's the proper schematic for driving this MOSFET from a microcontroller pin through this or this optocoupler?
The MOSFET will drive a motor @ 24V, 6A.
8
votes
2answers
2k views
Continuous rotation 'servo' vs DC motor
Under what circumstances should I prefer a continuous rotation 'servo' to a DC motor, or vice versa?
It seems to me that to use a DC motor, I'm going to need three pins from an MCU -- two for ...
8
votes
3answers
289 views
Measuring force developed by a robot
I've been playing around with a Lego Mindstorms NXT robot, gearing it for speed and power. To my dismay, when geared for power, it wasn't any harder to stop than when geared for speed -- I suspect ...
8
votes
2answers
2k views
Why connect capacitors to motor body?
So I've found a motor circuit which looks like this:
Since many users here believe that my hand-drawn circuit schematics are in fact pictures of flying spaghetti monster, I'll also provide a ...
7
votes
6answers
346 views
Why are battery-powered appliances and tools specified in volts? [closed]
"Powered with a suction of 18 volts"
Isn't this just a nonsensical "bigger is better" measure?
The thing you really care about as a customer is the motor's torque or power or RPM or something ...
7
votes
3answers
692 views
Capacitors and motors
Every RC car I've cannibalized has had a small ceramic capacitor soldered on to the contacts of the motors. What is the purpose of having this? What happens to the performance of the motor with out ...
7
votes
4answers
4k views
DC Motor control with an Arduino
This might be a simple, silly question, but I am wondering why I can't just connect a DC motor to an arduino board to have it running. One pin to the ground and the other to one of the PWM outputs.
I ...
7
votes
5answers
822 views
Synchronise multiple Mega boards to run multiple servo motors
My friend Jules asks:
The aim is to get as many servo motor controls as possible - looks like the maximum an Arduino will output is 14?
Digital I/O Pins54 (of which 14 provide PWM output)
...
7
votes
3answers
306 views
Why should I worry about a motor causing my supply voltage to shoot up when the back-EMF can't exceed the supply voltage?
I have heard people say that in motor control circuits, one must take precautions to keep the motor from feeding back into the power supply, causing the supply voltage to rise, consequently breaking ...
7
votes
2answers
1k views
Methods of filtering noise caused by DC brush motors
I am looking for any information that would help me reduce the power rail noise and EMI of DC brush motors. I am building a robot that is powered by 2 x 250 W 24V DC motors.
Thank you in advance
7
votes
5answers
418 views
Good motor supplier?
I'm looking to start a few different projects and stock up on some basic components - I was just wondering if anyone knows a good supplier of DC motors, stepper motors and servos?
I'm in vicinity of ...
7
votes
2answers
1k views
BLDC and three phase inverter
I want to run/control a BLDC motor from a DVD/CD-rom player and found a schematic how to do this, the so called three phase inverter (see right schematic on this page: ...
7
votes
2answers
210 views
Batteries for 12- to 24-V motors
I have some nice gear motors that run on 12 to 24 volts, and want to use them in a medium-sized mobile robot -- maybe 30 cm * 30 cm for the base. I only expect it to run indoors, or possibly outside ...
7
votes
2answers
620 views
What determines the speed of a homopolar motor?
What determines the speed of rotation of a homopolar motor?
7
votes
1answer
162 views
Ground noise and voltage drop problem
I have an RC device powered by a 3.7V poly battery, which includes a motor and a 40KHz sonar. The voltage across the sonar sensor is amplified and then adc-ed. The motor is driven by a 2KHz PWM.
When ...
7
votes
2answers
1k views
Can Arduino Mega handle 6 motors independently
I wonder if anyone can help me
I am modifying an ROV and thinking of using Arduino Mega
I am new to electronics and robotics and wonder if the Arduino Mega can control 6 DC motors independently as ...
6
votes
3answers
392 views
What would be the difference in a coil of wire and just a cylinder of solid copper?
Ok so I am learning about induction and I always see coils of wire with no insulator. So I was wondering, What is the significance of it being a coil of wire rather than just a solid cylinder since ...
6
votes
3answers
197 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 ...
6
votes
2answers
1k views
Can I combine the power supply?
Here's the circuit I'm working on, it's a robotic stringed musical instrument thing, that uses 6 DC motors and an Arduino Duemilanove -
The resistors are 0.25w 1KΩ
The transistors are TIP122 ...
6
votes
3answers
461 views
Braking with an electric motor
I realize that when you short the terminals of a motor, it stops the motor faster than just turning off the voltage. I was wondering if putting a large diode across the leads so that when the motor is ...
6
votes
2answers
249 views
Can I get a pair of schottky diodes in a single chip?
I'm building a motor driver circuit, and am looking at diodes to clamp the output voltage between the supply rails. Apparenly, I should use schottky diodes for this purpose.
My question is, are there ...
6
votes
1answer
1k views
How can I measure back-EMF to infer the speed of a DC motor?
I'm interested in measuring the back-EMF of a motor to determine a motor's speed because it's cheap and requires no additional mechanical parts. How can I measure the back-EMF when I'm driving the ...
6
votes
3answers
234 views
Is it valid to consider back-EMF in a DC motor equivalent to increased inductance?
I know that back-EMF can be considered as a voltage source in series with the motor which is proportional to speed. This is the common understanding, and I totally get it. Before I understood this, I ...
6
votes
3answers
3k 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 ...
5
votes
3answers
187 views
op-amp vs direct control
I'm experimenting with small motors (just building useless toys so far) and I'm wondering what benefit there would be to using an op-amp to control a motor (top circuit) vs just controlling the motor ...
5
votes
3answers
1k views
How do I know where I need decoupling capacitors?
I'm building a motor driver shield for the Arduino. Here's the schematics (please forgive the messy layout):
And here's the PCB layout:
I'm testing it out by breadboarding it while running a ...
5
votes
2answers
2k views
A proper way to determine correct voltage of unmarked components?
My kids have been tearing apart a number of different gadgets, from RC cars, to toys, to coffee makers.
There are a variety of cool little motors and lights in these devices that we would like to use ...
5
votes
5answers
349 views
Microcontrollers - Beginner questions
How do you determine how many sensors a microcontroller can use?
My understanding is you can't use C# directly on any microcontroller but you can use C# and communicate over the USB and look for a ...
5
votes
2answers
4k views
What is the purpose of carbon brushes in an electric motor
I just took apart our washing machine to replace the carbon brushes.
Was wondering why the machine stopped working when the brushes were worn down?
Also if the engine makes a wuring noise after you ...
5
votes
6answers
635 views
What causes “hard working” growling sound in a heavily loaded electric motor?
From my experience just any electric motor when under huge load would make recognizable growling sound. This would happen regardless of the motor type - brushed/brushless, AC/DC, small size/huge size ...
5
votes
5answers
1k views
Consume less energy by slowing down a 1 HP 220v pool pump motor
I would like to know if and how I could have my pool pump motor consume less energy. It is a 1 HP motor that works on 220v. It is my assumption that if the motor runs slower, then it will consume ...
5
votes
2answers
288 views
Driving a small motor: What's needed?
This question is very basic, but I'd like to ask it anyway.
I need to drive a small motor. I'm thinking about connecting it directly to 4 AA batteries and using a simple switch. Is there anything ...
5
votes
4answers
1k views
Driving a DC hobby motor using an AVR and a single power supply
I've recently begun experimenting with AVRs and am keen to progress beyond making blinkies to making things move. I've tried to start with something easy, but it seems I'm already foiled! What I'd ...
5
votes
5answers
5k views
Computer controlled water valve
I'm working on a computer-controlled indoor waterfall. One of the requirements is to be able to change the water pressure via computer interface. I've googled all day long and can't seem to find a ...
