Motors Definition and 336 Threads

An engine or motor is a machine designed to convert one form of energy into mechanical energy. Heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a heat engine, in which heat from the combustion of a fuel causes rapid pressurisation of the gaseous combustion products in the combustion chamber, causing them to expand and drive a piston, which turns a crankshaft. Electric motors convert electrical energy into mechanical motion, pneumatic motors use compressed air, and clockwork motors in wind-up toys use elastic energy. In biological systems, molecular motors, like myosins in muscles, use chemical energy to create forces and ultimately motion.

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  1. Irvin Atkins

    B Move in Space without mass exchange

    I did a thought experiment and I can't figure out what the mistake is. There is a system of 2 electric motors weighing 1 kg each with batteries in the Earth's orbit. The motors are rigidly connected by a 1-meter-long bar. If one motor starts rotating in one direction on a signal, the entire...
  2. patrickza

    I Lever arm comparison on a boat with toe-in motors

    I have a small catamaran that used to have two motor under the hulls spaced 2.7m apart. I've replaced those motors with outboards which are spaced 1m apart, and placed about 4.2m behind the centerline of the boat. Initially it was impossible to use differential thrust to turn the boat, but since...
  3. D

    Electrical VTOL engineering, motor RPM vs weight loads,

    choosing the right motors, the RPMs and weight/load capabilities of the motor/ rotors, combined abilities of electric motors working in tandem, choosing the correct rotors for lift m/ weight ratios, or designing your own?, should one add a small gas powered generator to assist in stable...
  4. Ahmedbadr132

    Power Efficiency of Linear Piezo Electric Motors

    Hi I want to know the power efficiency of linear piezo electric motors in percentile.
  5. rizwan25

    How to calculate HP for motors (alternators)

    Hi, I want to purchase a alternators that have 300 rpm and 20kw three phase can any body guide to me that which motor is best to spin this alternator means in HP. Thanks
  6. hugo_faurand

    Looking for advice on motors for a small windmill (for kids)

    Hello everyone ! I speak about energy to a fifth grade class. I want to build small windmills made of paper cup for the blades. The goal is to light a LED when the windmill is running. I was looking for a small motor to do the alternator. I found this one and I wanted to know if it could fit...
  7. C

    I Why do brushed DC motors only use commutators, and not slip rings?

    Commutators always generate unwanted sparks and bad EM interference. If slip ring can replace commutator in DC motor, then electric vehicle industry will love it more than multi-phase AC induction motor.
  8. F

    Improve Humidity with Kenmore Floor Humidifier Motors: Wiring Guide & Schematic

    I have a Kenmore floor model humidifier. It has 2 motors. Each motor has 2 coils. One coil has a balck and blue wire and the other has a red and white wire. These motors are wired in parallel. The control panel is bad an I would like to add a rehostat to control the fan speed and use it that...
  9. AmericaPacific42

    Are there cheap smartcar EVs with electric motors attached to wheels?

    There are small 15kw electric motors <$500*. LiFePO4 batteries that offer 60kwh** weigh <50kilograms, cost <$500, take as much space as the gas used to take. The hood could be removed or replaced with extra seats or used for cargo. Ultra-lightweight 3D printed magnesium bodies*** should be...
  10. Pipsqueakalchemist

    DC motors and Induction motor: What does "no load conditions" mean?

    TL;DR Summary: So I'm just confused when the question asks me to solve for the no load speed of DC motors and induction motors. Does no load condition mean that the output torque (Tout) is zero? This is what I was assuming so far for both DC and induction motor. Is no load condition the same...
  11. K

    Can Daisy Chaining Torque Motors Increase Power Output?

    Hi I recently discovered torque motors and think they would be perfect for a device I’m designing, except for the fact that the power I need isn’t available in the size I’m looking for. I’m wondering if two or more smaller torque motors connected to the same shaft can provide the same power...
  12. P

    Using Monopods for city travel utilizing linear induction motors

    This is another open ended question, exploring a space of design concepts, in similar spirit to this. I want to explore monopods with regard to travel in densely populated cities(even possibly intercity travel). The main idea is to use small personalized pods to travel in tubes(or tracks). The...
  13. I

    Is it possible to reduce back EMF in DC motors using shorting rings?

    Shorting rings (also called Faraday rings) are commonly used in loudspeakers to reduce the back emf that is induced in their voice coils. Could something similar, i.e. shorted turns of wire that are placed in the same plane as each of the windings in a DC motor, be used to reduce the back emf...
  14. B

    Torque Production in Eddy Current Motors

    Hi guys, The purpose of this post is to understand the actual phenomenon behind torque production in eddy current motors. This query is based on theoretical principles of torque production in AC motors. Consider a simple eddy current AC motor with a disc type or cylindrical rotor (Watthour...
  15. PhysicsTest

    Understanding the Parameters of Synchronous Motors

    I want to understand the parameters of the synchronous motor Rated Power -> This is the maximum power the motor can deliver -> Is it correct? I can operate the motor for any power less than this? Rated Torque -> This is the maximum torque beyond which the motor cannot produce? Rated speed ->...
  16. A

    Can two coaxial motors null each other's inertia?

    Hi all! I'm new here and hoping someone who knows something about ME or Physics can help me out ... and simple terms would be nice. I am working with two servo motors and would like to minimize the "kick" they make when starting or stopping since they do it quite frequently. Please excuse my...
  17. nduka-san

    Breaking hard ground with motors

    I'm trying to find a motor that would break hard ground what would you recommend, here is my research so far: My research is based on horsepower its bad research but I thought it might apply to a motor since its s also this is under the asumption of a 3 pound hoe people managed to do a lot of...
  18. F

    Engineering Continuous and discontinuous modes of series excited DC motors

    Here's my attempt: clc; clear all; Ra=1.8; La=150*10^(-3); Ls=150*10^(-3); Rs=1.8; Rt=Rs+Ra; ws=100*pi; c=1.25; vrms=240; vm=240*sqrt(2); f=50; T=1:0.5:50; for a=0:pi/9:pi/3 vt=(2*vm*cos(a))/pi wc=((ws*(Ls+La)/tan(a))-Rs-Ra)/c; x=[wc; a+pi]; Tc=c*(2*vm*cos(a)/(pi*(c*wc+Ra+Rs)))^2; for...
  19. A

    Selecting hydraulic motors and a pump for hydrostatic transmission

    So I'm trying to make a GoKart that utilizes a hydraulic drive for the front two wheels and a mechanical driveshaft for the back two wheels but my main questions are selecting the motors and pumps. I just want to clarify a few things since I'm not sure if I did my math right. The max RPM for...
  20. C

    Different types of electric motors

    I have to write a report about one of three motors AC type Motors, DC type Motors, Stepper Motors. I am wanting to now if anyone has any insight into which one I should talk about, which one has the most information and would be easiest to write a report on. Thanks
  21. baby_1

    Equation for trapzoidal motion in motors

    Hello, For a motor, we need to calculate the traveled distance and proper timing for its motion. Here is the trapzodial motion of our motor( we need that our motor traveled 20 degree in 2 seconds). (where t2=2t1) we know that the traveled distance is surface of our velocity diagram. So...
  22. T

    Why do AC motors pull high amps when they go bad?

    I used to work in HVAC. There are three main types of alternating current (AC) motors in residential air-conditioners and heat pumps: outdoor fan motors, compressors, and indoor blower motors. All three types of AC motors have the maximum number of amps stated on the nameplates of the units...
  23. D

    Starting Torque of Synchronous Motors

    It is pretty well known among electrical machines folk that large, salient pole electrical machines start typically with the field winding shorted and starting torque developed by current induced in the damper windings, acting much like a squirrel cage induction machine. The net machine torque...
  24. J

    Electromagnetic induction in motors

    why does an electrical motor produce an induced back emf which is equal to V-It when terminal speed of electrica, fans or electric drills is reached
  25. Boltzman Oscillation

    Engineering How should an H bridge circuit be analyzed?

    If I am given an H bridge circuit such as that below: How would I go on analyzing it? I would personally replace all of the transistors by their circuit models but then what would I do with the motor? Do I replace the motor with it's load resistance or is there more to it? I guess motors are...
  26. J

    Help Walk Me Thru Motor Sizing Calculations Please

    Summary: Hello; i am trying to work my way thru some motor sizing calculations on a semi-simple example so that i can more easily do it in the future. Could i get some guidance? Hello: I am trying to develop a good system for sizing motors (generally steppers). In the past i just guesstimated...
  27. Mathew Joseph

    How to make the power factor of induction motors be a leading power factor?

    Hi guys, This month onwards our power distributor says that we only get powerfactor incentive when only we make the powerfactor leading and in between 0.95 and 1. Our industry fully consists of induction motor and compensative capacitors are provided but this month onwards we have to keep the...
  28. Z

    Can a 74 Year Old Find Answers in a Tech-Savvy World?

    Hi everyone, thanks for accepting me into your membership. I’m a 74 year old male, retired from the ministry & school system. I enjoy woodworking, genealogy & especially woodturning. I have always pitteled with ways to make do with what I had on hand. In other words looking for a “poor mans”...
  29. T

    B Calculating Stress on Car Motors with 4 Wheels

    If I were to have a theoretical car with 4 motors controlling the 4 wheels(each with a radius of 5 in and a width of 1 in) and the car was 100 pounds, how much stress would be exerted back on to each motor?
  30. J

    Has anyone moved 40lbs using 4 sets of 10lb motors?

    Problem Statement: 40 lbs Relevant Equations: 10 times 4 I wanted to know if anyone has moved 40lbs using 4 sets of 10lbs motors instead of a motor that can move 40lbs I am testing using 4 small motors instead of 1 big motor thank you
  31. M

    Two Different Designs of DC Motors

    Hello, I have two designs of DC motors. Which one is more efficient? I believe what is in question is the location of the communicator. Whether it should be closer to the out piece of the shaft turning the gears? Or should it be further away towards the end? Does this make a difference...
  32. M

    Overvoltage on the power supply to compressor motors

    Hope you may help me to understand how detrimental to compressor motor would be if it operated at voltages exceeding the manufacturer's specified 400V by 12%? so 448V. I have vendor engineers saying since it exceeds 10% they cannot safely run the plant and of course the voltage monitoring relay...
  33. A

    1-10 kV power supply recommendations DIY electrostatic motors

    I am trying some projects that involve building some very simple electrostatic motors. I attached below figures of the kind of electrostatic motors I am trying to make. What I can't figure out is what kind of high-voltage power supply I should use, presumably 1000 to 10,000 volts is what these...
  34. N

    Lenz's Law for a rotating PM motor rotor spinning in a thin CU tube

    The motor is required to operate at its resonance frequency and I am looking to add a thin-walled (0.010") copper tube inside the stator bore to add some damping. The current motor air-gap is 0.015". If I install a copper tube in the stator bore bonded to the stator and leave a 0.005" air-gap...
  35. X

    Engineering Questions about motors (practical tests)

    Problem Statement: Questions about motors (practical tests) Relevant Equations: synchronous/induction motors Hey guys, Some practical questions about motors :) Let's admit I have to test one stator winding phase (in high voltage, we test one at the time). During this test what do you do...
  36. anorlunda

    Remarkable New Marine Propulsion Systems

    I recently came back from a cruise on MS Eurodam. The ship was equipped with two 17.6 MW Azipod propulsion systems. The captain explained a bit about them in a Q&A session, and I researched a bit more because I'm curious as an engineer. I'm sharing it here on PF for the benefit of other...
  37. J

    Why don't electric motors use exciter coils like generators do?

    I remember (long ago, in college physics) learning about electric motors and generators, specifically about the "exciter" coils in generators which did a better job than permanent magnets, because of a sort of "turbo" or force-multiplier effect. I notice, however, that while basically ALL...
  38. L

    Engineering What types of motors are used in forklifts?

    Homework Statement what type of motor is used in forlift and why what are the requirements i can find much on forklifts Homework EquationsThe Attempt at a Solution i guessed ac induction squrriel or wound using high torque and good speed regulation
  39. 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...
  40. J

    How Do You Calculate Motor Size for a Small Electric Vehicle Project?

    Hello all, I have a project in which i need to design a small vehicle which is able to carry 4kg for 10 meters. I have took it up to 5kg as the frame and wheels add up too 1kg. So the total weight will be 5kg. Acceleration isn't a priority, but 0.5 m/s I would be fine with. The wheel have...
  41. G

    Induction Motors: Rotating Magnetic Field & AC Frequency

    Hi, Can I please ask how the rotating magnetic field (due to the 3 phase ac) is changed? Is it due to the frequency of the ac supply that it can speed up and therefore drag the rotor along due to induction. If it is due to the changing frequency input that mimics a faster rotating magnetic field...
  42. S

    Homopolar, Brushless and Brushed DC Motors

    I've seen examples of each of these types of dc motors. What I haven't found is a dc motor that doesn't use pwm, commutators/brushes, or some sort of slip contact. Is there a such thing? If not, would there be a demand for such a motor?
  43. H

    Ansys Maxwell Modeling of Switched Reluctance Motors

    Hi Everyone i'm new member of Physics Forums, my research field is about Switched Reluctance Motors i have question about Optimetrics in Maxwell! my question is: How can Optimize Design Parameters ( like Outer and inner Diameter of Stator and Rotor or Embrace of them) of a Switched Reluctance...
  44. cpcoe

    AC vs DC servo motors in large scale cable robot design

    hi, I'm designing a 50ftx50ft, 8-cable Cable Driven Parallel Robot and am thinking this is a pivotal decision. the corner posts are 10ft tall and the machine should be able to lift 100lbs at least 5ft off the ground. traveling speed of the end effector is less important than accuracy but I'm not...
  45. A

    Automotive Can two motors rotate about the same axis?

    can we add two motors to rotate same object on same axis or is it impossible? for a stronger rotation and torque two motors rotating object in same direction
  46. Osvaldo

    Understanding magnetic balance in AC induction motors

    I need to find out how calculate magnetic forces appearing in AC induction motor rotor when it is not magnetically centered inside the stator.
  47. R

    One of my wheelchair motors overheats and stops working

    Hi can anyone help. I use an electric wheelchair to get around and can only walk a few steps with a wheeled walker. Yesterday I went to my local out of town ASDA, a 1.5 mile trip approx through an alley/Public Footpath, I have done this many times before. This time I was about 3/4 of the way...
  48. rishi kesh

    Lorentz force and linear motors

    I have a picture below please have a look at it. The guy is using two conducting rods placed parallel to each other and placed below it are magnets. When battey is connected to rods and a conductor is placed over them it starts to move.That works according to flemmings left hand rule. I was...
  49. K

    Help with reducing AC Mains voltage sag at large chiller motor startup

    A 4160v chiller motor is drawing too much power at start-up. Utility company only let's them run it once or twice a year because of it. It dims all the lights etc.. It was originally a primary reactor starter (2 contactors). The PR was replaced with an auto-xfmr and wired the same. So now it’s a...
  50. J

    Why do more magnets affect how long a homopolar motor spins?

    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...
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