Questions tagged [motor]

An electrical actuator that converts electrical energy into rotational motion or sustained linear motion (linear motor). There are many types of electric motors. If the specific type of motor is known, it is helpful to use or add a more specific tag, such as dc-motor, brushless-dc motor or induction-motor.

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Using MOSFET to control positive side of motor?

I want to control the speed of a DC motor, but the chassis is connected to the negative side of the motor, making it impossible to use the MOSFET to disconnect ground. Is there a way that I can use ...
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Refrigeration compressor circuit, help trying to reverse engineer it

I have disassembled the motor controlling circuit for my refrigerator. I am trying to understand how it works, so I hopefully reduce the start surge-current and make it work with my 1000w inverter. ...
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Powering a Servo: Do I need a separate power source?

I have a project that utilizes two strong digital, coreless servo motors. Whenever I use DC motors, I usually need to have separate power sources for both the microcontroller and the motors (due to ...
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What sort of electric “motor” would I need to launch a puck?

As the title suggests I am looking at making a hockey puck launcher so I can do some off ice technique training as a goal tender. I have no one to train with so I wanted to create a puck launcher ...
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Which informations do I need to calculate the efficiency and horsepower of a 3 phase induction motor?

As far as I know the magnetic force is responsible for the motor rotation. So, horsepower of the motor is mostly related to magnetic flux on the coils (windings). Also magnetic flux is directly ...
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What is the relation between the stator current and motor rpm for an AC motor?

A 3 phase AC motor is rated values are: 970 rpm, 50Hz, 380V delta 47A. A VFD drives this motor for obtaining a constant wind-speed which rpm is proportional. The thing is when 885 rpm the stator ...
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In a brushed DC motor, why do the brushes have springs?

In trying to understand brushed DC motors, this post has been very helpful but I still have some fundamental questions about the brush mechanism. For instance, what is the purpose of the spring? (...
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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 ...
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How to find out whether I have a unipolar or a bipolar stepper motor?

I have one stepper motor. There are six wires coming out of that. How can I find out weather I have a bipolar or a unipolar stepper motor? Note: Related, but not a duplicate: Unipolar and Bipolar ...
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How to re-magnetize a permenent magnet motor of small size (model railroad)?

I have several small DC motors where if I place an extra magnet to back-up the included magnet, the performance seems to improve significantly. These motors are 30-40 years old & their ...
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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 ...
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Overclocking my toothbrush

I use these toothbrushes: http://www.amazon.com/Oral-B-Advanced-Toothbrush-Vibrating-Bristles/dp/B00336EUV8 They tend to run out of battery quite quickly. I'm happy to keep buying more because ...
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Braking a DC Motor

I've been working on a lab for my electrical class, and I can't quite seem to find the answer. I have a DC motor that plugs into a 120V supply,from the supply it is connected to the shunt field, then ...
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How to interpret diode-mode readings from a multimeter

I'm using this multimeter to examine a heat gun fan. The fan has four contacts placed in a circle (well in a square inside a circle). Two opposite each other are labeled ...
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DIY small motor that turns for x seconds every y seconds

I'm a civil engineer, hiker, and hobby photographer. I am trying to build a little device that gently turns a small motor on every x seconds, keep it on for y seconds, and stop it for z seconds. For ...
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Reversing direction of a 115v ac motor using Arduino

I have a 115V brushed motor that I am controlling via Arduino. The manufacturer says it draws 1A but I'm not sure if that accounts for the initial current draw to turn it on. I've had great ease and ...
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Can I use a DC SSR that is switched by a PID controller to control the speed of a 12 V DC fan?

This is my first post here. Let me start by saying that I do not have an engineering background. I tinker with electronics in my spare time (Arduino, solid state low-power guitar amps, etc.), but I do ...
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Arduino Speed Controllers for RC Cars

This may be a lame question but, Speed controllers on big RC cars can they be controlled from Arduino? If yes, do they have a standart? do I control them using PWM values? What should i look for if I ...
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How to protect a P-channel MOSFET when driving a motor?

I want to switch a 12 V DC automotive fuel pump in a bench test rig using a P-channel MOSFET, as follows: simulate this circuit – Schematic created using CircuitLab This is a simple on/off ...
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Stepper motor phase

I have a question related to stepper motors. What does the "phase" of a stepper motor mean? I mean when we say that a stepper motor is a 2 phase stepper motor or a 4 phase stepper motor, what does it ...
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DC motor causing noise on the power line

I've been building a circuit where I'm controlling a motor using a bluetooth module + phone. I've been having some problems, which mostly are fixed (see topic: previous topic). The main problem I'm ...
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671 views

What does the output current rating from an H-Bridge's datasheet really mean?

I bought the H-Bridge VNH7070BAS from ST because it would drive up to 15A, but when I test it, it only reaches 6A and then it shuts down. What does that value really mean? How can I get the output ...
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how to add a motor to a potentiometer?

I have an old piece of analog gear from the 70s and I want to motorize the variable resistors on its panel. I don't want to replace the existing pots with motorized ones but rather to add a motor to ...
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6k views

Recommend motor type to turn baby rocker, into auto-rocker

Would like to convert a baby bouncer (like this one), which requires continuous manual effort to rock it, into one that use electro-mechanical means to auto-bounce. However, my aim is to make these on ...
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962 views

Relay control of AC motors, handling turn-off kickback

I've been researching how to control a smallish AC-motor using a relay, and more specifically, how to turn an AC motor off using a relay. This is a subject that has been up many times at this site, ...
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4k views

How to tell if brushless DC motor is wired delta or Y?

I have a brushless DC motor I'm working with, do not have any spec. sheets for it. How can I determine if it's wired in delta or Y formation? There is nothing on the label that indicates this. Here'...
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How many servos can I run on an ATtiny85?

This is my first time asking a question on this website, so please correct me if I'm doing something wrong... I have been working on a small project which runs three Servo motors on an ATtiny85, ...
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366 views

L6203 H bridge (very) high Rds on

datasheet: L6203 DMOS FULL BRIDGE DRIVER I was testing this H bridge on wire wound high power resistors. I have noticed a high drop in the output voltage. The measurements taken are as follow: Vin=...
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Converting a DC motor to a generator

Can ANY DC motor become a generator if torque is applied to the shaft? example: Produce-Electricity-from-a-DC-Motor And by any, I mean the really cheap ones too. Or is there a specific type of motor ...
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How does the power usage and voltage of a universal motor change when running on DC?

I have a 2400w universal motor from an AC powered garden blower (230V @50Hz here in Australia) and am wondering what voltage and power requirements it would require from a DC source to give roughly ...
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AC motor Low RPM problem

I'm working on a controller for ac induction motor and it's spec is given below. I could control the speed without any trouble at higher speeds like 2000 rpm and above. I'm using TRIAC phase angle ...
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Can I drive a three phase induction motor with this method?

I have an idea to drive induction motors in a new way. I call it Variable Torque Drive (VTD). You are all familiar with VFD which utilize variable frequency and try to keep the torque constant. This ...
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1k views

How to use a salvaged brushless motor

I recently took apart an HP LaserJet 1320 laser printer to salvage parts from it. Along with 3 solenoids, a fan, lots of gears, 83 springs, and 71 feet of wire, I got a large brushless DC motor with ...
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Resistance and Inductance of a ceiling fan motor needed to spec snubber

I'm looking to specify (well, suggest) a RC snubber network for someone over on diy.se who is having EMI problems with his ceiling fan knocking out his TV briefly on turn-off: https://diy....
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94 views

What is dynamic stability in an induction motor?

What does dynamic stability mean in terms of a 3 phase induction motor when evaluating a slip/torque curve?
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Can you use reverse as regenerative braking in a 2 quadrant motor?

I'm having trouble understanding 4 quadrant versus 2 quadrant drive for a 3 phase permanent magnet brush-less motor. Let's say you are riding a scooter with such a motor at a certain velocity forward ...
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Single Phase Induction Motor Wiring help

I have purchased a Single Phase Induction Motor that runs anti-clockwise, I require it to run clockwise however I am unable to figure how to change the wiring to do this, any help would be appreciated....
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Arduino Ardumoto

I am using Arduino and Ardumoto dc motor controller to drive a DC motor. I am kind of at lost because i have gone through 10 different motors. They either don't work( not enough power ) or not ...
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Calculate rotor slip without knowing synchronous speed

I am given the rated values of a squirrel cage induction motor: A 300hp, 2300V, 3‐phase, 60Hz squirrel‐cage induction motor turns at a full‐load speed of 590r/min. What is the approximate value ...
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How to wire 3 phase motor to VFD

I am trying to wire a new motor to a variable frequency drive (VFD) and having some trouble figuring out how to wire the motor to the VFD. The motor is a 1 HP, 3-phase, 208-230/460 volts, and I'm ...
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435 views

What is the type of this legacy motor and how is it supposed to be controlled?

A friend of mine is going to give me an old Dayton 8F047 which I would like to recycle, but it is now obsolete and I cannot find anything other than a schematic which is reproduced below. simulate ...
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Controlling motor with potential on 2 points

I have 2 nodes where minimum voltage is 2.7v and maximum voltage is 5v. I would like to turn ON a motor when both nodes have 5v and turn off when both nodes have 2.7v. Node1 - 5v & Node2 - 5v ...
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How does a capacitor reduce voltage drop in a DC motor start?

I know that a capacitor stores charge: C=Q/V but what i don't understand is how this would reduce the voltage drop caused by high current draw. My theory is that the capacitor would need to be in ...
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706 views

How to filter noise of different frequency based on motor power

I am taking torque readings from strain gauges on an actuator and trying to filter the signal to look usable. I have already put in place a median filter that reduces sporadic spikes. When I have the ...
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197 views

Can every voltage source accept fly-back diode's current?

A diode is used parallel to the motor (or inductive load) in order to prevent damage to the switch because of back-emf voltage. Now, that back-emf voltage actually produces a current and by using a ...
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1k views

Is there any advantage in running a universal motor on DC power?

Since a universal motor can run on AC or DC, is there any advantage of using DC over AC? If so, what chracteristics of the motor improves, if any. What about noise levels?
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Modelling a “single-phase permanent split-capacitor motor” in LTspice

I'm planning to use an AC fan in an LTspice simulation. The AC fan is made up of a single-phase permanent split-capacitor (PSC) motor. Here is the actual fan: http://uk.rs-online.com/web/p/axial-fans/...
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If single phase supply can not create rotating MMF, how does Induction motor generate torque?

I do understand that in a Three phase Motor, a rotating magnetic field is produced in stator and the induced magnetic field in rotor tries to aligns itself with the stator field which makes the rotor ...
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17k views

How do I change rotation direction of single phase fan motor?

I have a single phase AC motor. I found it from Photocopy machine. That motor same to Fan motor. It has a capacitor to make phase angle. I don't know what is the correct name of my motor. Can I ...
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Dealing with Motor Noise

Generally 0.1 μF 50 V ceramic capacitors are connected across the motor terminals to reduce noise. How this value is decided? Does it depend on the motor rating?