Motors Definition and 325 Threads

Hi All, My daughter did a science experiment on homopolar motors. The only variable was the number of magnets on each motor. We found out through the experiment that the more magnets we attached to the motor, the longer it spun before the battery died. I'm assuming it has to do with the...

I need help in explaining how electric bell uses motor effect.

This is related to steel wire pulling machine. I have 2 cases. In CASE-1: ONE MOTOR 160 kW AND CASE-2: TWO MOTORS 129 kW Each. i.e 2x129 kW Which case would have an efficient pulling force and efficiency Case 1 or Case 2.

Hi, In an AC 3-phase induction motor (i.e. asynchronous motor) rotating magnetic field is produced by the stator and in this case rotor consists of simple cage having metallic bars or with coils wound around the rotor. The rotating magnetic field magnetizes the rotor and attracts it. As the...

Since I discovered the homopolar motor, it has fascinated me a lot. Not because it has any practical use, but it works in spite of a non gradient magnetic field. Normally, an electric motor works because the rotor is allways "chasing" a sticky magnetic spot. The magnetic gradient between weak...

So I know if you move a charge in a magnetic field it induces voltage and hence a flow of charge is created which is current. ( Please correct me if I'm wrong). But that's pretty basic right. However, I'm having trouble understanding the use of split rings in the functioning of a motor. I would...

i made a small thing for my nephew, i connected two small fan motors with one switch and one battery but everytime one of the motors jams or he grabs the fan the other fan rotates faster. why is that? also tried to increase number of batteries but same thing

I've dissected several hard disk drives to scavenge the "linear" motors which move the read-write heads across the disk platens. At first glance these look simple enough. There is a pair of high energy permanent magnets in a yoke which provide a circular sector shaped high magnetic field in a...

Hi there, I attached an image of a basic linear motor. I'm a little confused if I use the right hand rule or left hand rule. I did it both ways and I think the left hand rule is the only rule that allows for a force being applied to the right. I assume the current is going down rather than...

Hello everyone! This is my first post here so please excuse me if I don't have the format right yet. Background: I'm a Mechanical Engineering student working on a robotics team and I'm tasked with designing the wheels. The robot is currently using 5 in radius wheels with old motors. The...

How does one calculate the amount of HP a motor makes when it is not running at a full 60Hz? The reason for my asking is a customer wants to use a 1/4HP motor and a gearbox to vary the speed of a conveyor. At a full 60Hz we are figuring 1750rpm for the motor, and through the 7:1 gearbox the...

On average, which has higher power to weight ratio between the two? So on average, if both weighed the same, which one is going to have more power?

Is it possible for an electric motor to exist (based on our current understanding) which is capable of applying continuous upward force upon an object, enabling that object to fly or lift above the air?

From what I've understand now, it is like in a brushed DC motor, the more poles you have, the less RPM but higher torque. Can anyone confirm?

I read that the Tesla electric motor is able to achieve its remarkable power to weight ratio of 8.5 kW/kg, about 10 times better than a typical gasoline engine, because it tightly winds its copper wires in its coils therefore being able to carry more current in the same space. If so, then we...

Hello all. Thanks for taking up your time to read my post. I have ordered http://uk.stepperonline.com/download/pdf/11HS20-0674S-PG14.pdf stepper motors. I asked the seller how many revolutions the motor can achieve in a minute and they answered 43. I calculated (13 + 212/289) * 200 * 43 / 60 to...

Homework Statement Would a switched reluctance motor be described as a non linear load? Since it is switched on and off rapidly to turn the rotor, does that make it non linear?

Long story short, on single-phase capacitor motors, large values of capacitance are used for starting and much smaller values are used for running. Yet it would seem that the amount of electrical phase shift needed is dictated and fixed by the physical relationship between the main and auxiliary...

Basically, I am looking to buy some cheap motors. Basically, I am trying to build a small 1 person car that can drive on the sidewalk. Trying to find out the best and cheapest small motors. Preferably with a throttle. These motors would only need to move 250 lbs at 20 mph or 30 mph. I want...

Motors are supposed to rotate inside because of changing magnetic field.. but when looking at high speed fan.. I'm thinking how can the changing magnetic field responds so quickly... is the rotation or changing magnetic/electric field the same speed as the fan?

Homework Statement You're an electrical engineer designing an alternator (the generator that charges a car's battery). Mechanical engineers specify a 10-cm-diameter rotating coil, and you determine that you can fit 250 turns in this coil. To charge a 12-Vbattery, you need a peak output of 16 V...

Hello, I appreciate if somebody could help me to resolve this. I bought a geared DC motor from a store. I would like to obtain the following information: Resistance, Inductance, Back EMF constant, torque constant, and the voltage caused by Back EMF when the motor is supplied by a voltage input...

I'm a physics teacher and I've found it hard to explain motor's working to a couple of students.

Hi All, I'm hoping you all can help me with what I think should be some relatively simple calculations. I'm looking to determine how large (diameter / weight) of a flywheel a particular AC motor can spin from a stop to full RPM given the torque / HP of the motor. For instance, if I have a 1/3...

As a EE student, I studied Induction motors: three and single phase. I saw somewhere that Tesla's autos are using induction motors feeded by batteries. But I've never heard about DC induction motors.. I also heard that Tesla autos have torque constant for every speed, but that's also not how...

Hey PF, first time here, I have a problem I can't seem to solve! Any help is appreciated. I am using some DC motors with peristaltic pump heads to pump water (picture). I was having issues so I've broken my circuit down to the bare basics: 1) 12V regulated power supply 2) 12V motor 3)...

Hi I'm working on a project in school (or at home) about brushed DC motors. I have recently built a prototype myself but instead of using permanent magnets around the armature I'm using an electromagnet from another motor that died. I intend to build another motor using the same armature but...

Hi All, I've been reading up on hybrid vehicles and how the Honda Insight has an electric motor attached directly to the gas engine driveshaft. Their combined output causes the wheels to spin. My question is in regards to when the electric motor is off but the gas engine is on. Why doesn't the...

Homework Statement Homework Equations p=nsf δ=mϒ Kd=[sin(δ/2)]/msin(γ/2) Kp=cosε/2 e.m.f=4.44TφfKdKp The Attempt at a Solution i do not know why pole pair =2 and it is short 2 pitch. how can i find pole pair and short pitch from its original developed diagram? i know that Phase spread=60(we...

I noticed that I could get a minor belt off my 3 x 1.5KW compressor. I attached my meter to a mains supply 'socket earth', and to 'the chassis'. I watched the AC voltage gradually rise... perhaps increasing in speed slightly as the potential difference increased between the chassis and earth...

I would like to know what gear ratio i would need for my electric longboard. The goal is to run the longboard at 30 - 40 km/h at max power. Me and the longboards weight is approximately 65 kg. The brushless motor i am running has an rpm of approximately 18000 rpm (as it is an airplane engine)...

Hi, I saw few threads here about air-gap in motors, and I wonder what if we ignore mechanical issues and make an "iron-gap" in the motor. for example: in linear motor(e.g. this cute one: https://www.physicsforums.com/threads/linear-motor-equations.794499/) if we make the tube between the stator...

I am trying to figure out the best way to hook up two 12v DC peristaltic pumps to run as close to the same speed as possible. The manufacturing tests had the pumps running within 10ml per minute which is acceptable; when I hook the pumps up in series they are not even close. When hooked up in...

Hi, We have a machine from Europe with three 400V 50Hz 3 phase motors. Assume we only have 240V single phase available. There may be 480V single phase available. I don't currently know how many poles the motors have. Assume they are not made for both 50Hz and 60Hz as some are. Power consumption...

So, I'm working with a DC shunt wound motor and I want to calculate the actual voltage production on paper mathematically before building. I have been studying the biot-savart law and understand it to a fair degree. One of my questions is after you get your measurements in Teslas from said law...

How electricity passing through a conductor produces magnetic field around it. How an induction motor works. The energy or electricity which passes trough green earthing wire is transmitted into the ground. Why this energy is not conserved and can be used in future. All these three things are...

Hello, I'm working on my kids ride on cars. He has two of them. On the first it was 6V and came with one motor on one wheel. I updated it to 2 motors, one on each wheel and 12Volts. I put in a DPDT switch so he could select high and low. On high the motors are run in parallel and on low they...

Hi all, I have a 1 HP capacitor start motor (old, c.1950) that runs an air compressor in my little workshop. When it's running, the lights in the shop and the whole house dim and brighten rhythmically, at about 5 Hz. This, of course, is related to the compression cycles of the compressor, but...

Hi, I am doing a design project but I'm kinda stuck with choosing motors because i am not sure of the required torque. My project is a handicapped golf vehicle powered by 2 motors, so it would need to be able of climbing steep gradients. I currently have an equation but I am not entirely sure if...

I have a dilemma with the design of a device I want to build which is acquiring the correct size motor (shape & power) in my price range (even finding one within specs). I have found that the motors from cordless drills are ideal for this application (due to size, price and availability) so...

I have been reading up on electric bike motors, there are a few things regarding size and wire gauge that have me confused. I have seen disassembly videos of around 300 watt electric bike motors with planetary gears, and I can't see how anyone can push through 300 watts through the wires without...

why single phase induction motor is commonly used for low HP rather than integral HP like 1,2,3HP... i understand that single phase gives low power...but say you have designed such that your motor delivers 10HP for rated voltage and current...why such single phase machines are not common?can...

So for a school project I got to design an electric car that can meet minimum range and top speed requirements for how heavy it is. I have calculated the amount of power needed(kW) for its heaviest load situation to reach the min speed and range, along with the necessary energy(kWh) required...

Hey forum, So I plan on creating a remote controlled quadcopter and I have a query regarding its propellers' sizes. I read that small propellers require motors with a high KV (RPM per volt), and large propellers need motors with a lower KV. There seems to be a way of determining how to match...

I'm building a hybrid car for my kids. I'm up to speed control and hitting a few hurdles. The set up is 4 x 12VDC motors, one to each wheel through a reduction gearbox. I've wired them to a single bus, and have used 4 standard relays to deliver forward/reverse. I have tried varying the speed...

I understand the diagram above where the blue stuff might be mercury like in Faraday's mercury motor. I don't understand why the liquid moves but... it is a conductor so why doesn't the current (moving electrons) feel the force and leave the liquid stationary? Similarly in this motor its the...

Hello community, I am building a device for which I will be using five Stepper motors (each 5v, 3a) and one brushed DC motor whose speed has to be varied and operates between 12V and 48V (350Watts). Also I have a heater which runs at 12V, 40Watts. My question is: How will I best power these...

In cumulative cascade connection of two induction motors, why does the net speed reduce? Also, how are the torques of the two motors in the same direction?

Hi Guys I'm hoping someone can help me out with a problem?? I have just started learning about DC motors and I have hit a wall on how to solve the following problem- Q.The output of a series d.c. motor when connected to a 230V supply and running at 1320rev/min is 3.8kW. The supply current for...

Homework Statement Homework Equations Hello, i have been thinking, what couses a dc motor to have let's say 6volts drop across him. I was thinking that since it is just a coil it should have a verry little voltage drop, but afted testing on breadboard i figured out that it have near 6 volts...