Dc motor Definition and 323 Threads

I just saw a question saying there's an induced current in a dc motor. i always thought dc motors' electromagnetism is separate from the ac generators' electromagnetic induction? if there's really an induced current, how will the overall system work then? wouldn't the rotation be opposed? also...

No solution given

Hi there, I have done an experiment measuring the voltage across the terminals of a dc motor, whilst running and then by holding it with my fingers to stop it. Done as demo for my high school class. The voltage reading was higher when the motor was running, which was against my expectations as...

hello take a mechanism driven by a DC motor in automation books you find transfer functions such as : G(s) = k1/s(s+k2) normally it s assumed that the moment of inertia referred to motor shaft is a constant the point is that in general it is not a constant take for example a slider - crank...

I'm not sure if you would call it a "Parallel Impeller," but the pics below should tell the story. I'm designing/3D printing my next RC boat from scratch, and I wanted to try something different from tried-and-true propeller and shaft system. Reasons? 1. Fun. 2. Using a "wet" brushless motor...

Summary : i have tried changing the batteries and wire,but still nothing. The wire is insulated and the coating is removed at the ends of the battery and the point where the wire touches the commutator. I have not counted the number of coils. This is required for a school project. If someone has...

Hi so I'm making a DC motor for my school project and I have no clue why it doesn't work properly. I used copper wire to make the coil (around 50 windings) and put that around a wooden axle (the windings and the coil itself are secured using tape and cable ties), I have a split ring commutator...

I need help with a Baldor dc motor, 15kw 240 volt armature and 150 volt field, I don't need the 15kw and so want to feed it with 150 volts to both field and armature, does anyone know the effect this will have on the motor, can I cause damage, what would be the approximate power output, I know...

As a part of our physics high-school self-study, we are making a stroboscope. We have a small 5-V DC motor that powers the strobe disk. It works as expected, but, clearly, the motor makes the disk spin at a constant speed. Is there an easy, but effective and reliable way to control its speed...

Hello, so for this question I know how to solve it but I still have a few questions. First when the question means it's rated at 20 HP and 600 V, it's referring to the source voltage and Pin correct? Also in order to solve this question, the rotation loss Prot was neglected. This was because at...

Hi, I wish to build an orbital shaker (a bigger version of these examples: https://learn.adafruit.com/crickit-lab-shaker https://www.thingiverse.com/thing:2983846 As my aim is that it will work continuously for months around 100rpm what is preferred in aspects of heat and weight on top of...

I am a mechanical engineer and my experience with electrical systems is almost nil. The concept of a simple DC motor explained here was quite interesting, especially the need of a commutator part: And then I checked this DIY simple DC motor here and was confused because there was no...

Hi all I am Belgian and I have difficulty with english formulas. I'm trying to calculate the power and torque required of a motor to rotate a load. Here is the problem: I have a motor (axis up) on which is fixed a cylindrical load of 15Kg. The diameter of this load is 400mm Calculate the power...

hi everyone, i need to build a dc motor for my school project. I have used copper wire for the turns (60 turns), wood to build the structure of the armature and commutator. i have used neodymium magnets as my permanent magnets and paper clips as the brushes. I tried using a 9v battery with a...

Summary:: I have built a DC motor as a physics project, it has neodymium magnets, copper split ring commutator and insulated copper wire. It connected to a 12v power pack. There is definitely a proper current flowing because it creates sparks and the copper coil becomes hot. When I turned on...

So I am doing an experiement about DC motors, and I would like to know why the efficiency plot looks like a parabola. What is the structure behind that. Thank you in advance

I use a 2 Relay Motor module to control Direction on a motor (linear actuator). When Relay A is active, actuator retracts. When Relay B is active, actuator extents and Led Module is activated. After some repetitions Led module fail. Cause of the fail? I believe Surge voltage, although i am not...

^because in my textbook, the set up doesn't even show the direction of dot/cross at points A/D, so we won't know the direction of current. then how are we supposed to use fleming's left hand rule to determine the direction of force?

Hi Physics! And again, thanks for the membership! I’m about to build a robot just with some old parts I have. The main thing is the motors. I have 2 DC Motors Specs below. (It’s a MFA975D Series with gear ratio 49:1) Operation range(Voltage): 12V No load = 147RPM Nm = 1,8 Stall Torque =...

I am designing a reciprocating saw that I plan to use a scotch-yoke mechanism to convert rotational kinetic energy into linear kinetic energy. I want to spec out a motor and the final thing I need to calculate is the required torque. The motor must be 12 Volts and I need to know the required...

I am looking for a recommendation on the proper DC motor to purchase for a custom project. My project involves vortexing water using an impeller, which resides in a 1.5" OD stainless shaft residing in sealed bearings - not a whole lot of resistance, easily turned by hand. I need to spin this...

This is the explanation in the section of DC motor Based on the above explanation i have drawn the torque curve. Can you please confirm if it is correct? In the initial position the torque is maximum and when it reaches the diagram 2 the torque is 0 and then it is maximum.

https://d2vlcm61l7u1fs.cloudfront.net/media%2F9b2%2F9b24aa39-e135-4529-9eaf-29a3cd057502%2FphpubWKNH.png

A few years ago, I bought a Accurite weather station which has a wireless connection (not wifi) to a unit in doors. I was standing near it on a quiet sunny day and I heard a motor running. It turns out that is's a fan that blows over the temperature sensor to make sure it measures the actual air...

I'm a relatively new entry into the world of electronics so my understanding of what is possible may not be an accurate one. In a nutshell, I would like to have a DC motor act as a torsional spring with some variable virtual spring constant (k). The motor, or "spring", would act against an...

Sirs, Am facing problem in dc drive that is dc tacho fault . I have checked tacho and found values of armature resistance are same in all segments in commutator. But motor speed not in control. It is automatically varying and suddenly stopped. Is there any bypass method available for tacho...

I want to move a belt quickly with a geared motor and with a high torque. Given a limited space, what would be better? 1.Stepper with a gear box or 2.DC motor with a gear box? (Both gearboxes would be the same ratio) I believe the answer is a DC motor with a gearbox but I need someone to...

At night, the house is totally silent and I want to make a silent winder to keep my automatic watch topped up. At the moment, our clock radio makes a disturbing whine all night and it disturbs us (real princesses) . I'm in the feasibility study stage. A winder needs to rotate about 600 times a...

i don't get how a dc motor will overspeed when you don't give the field windings power cause you need flux to make the motor move so how will taking away the flux make the motor go super fast

Hello everyone, I see videos showing the output torque can be increased by using gears and this is usually demonstrated with DC motors (simple DC motors can be removed from toys). I understand the general logic: * The DC rotates in a high speed. * The gear system reduces the output speed. * If...

Hi, The picture below shows a DC generator. The magnetic field is uniform. As the coil rotates clockwise, the right side of coil is moving downward and the left side of coil moves upward. Using Fleming's right hand rule, one can deduce the direction of conventional current in both sides of...

Hi. I am new here. I have a question on how to speed control a DC motor running a pump. The pump is a seawater cooling pump cooling a large V8 motor. Therefore I need to control the RPM, based on the temp of the V8 Motor. Any ideas?

First some basic figures which are very rounded as I'm interested in the approach to the problem rather than accuracy of the answer at this stage: The field current will be 500/220 = 2.2727 Amps, and so power is a fixed loss at 1136.36 Watts The armature current is 45 - 2.2727 = 42.72 Amps. At...

What are the negative effects (if any) of running a compound DC motor with the series field open? I’m troubleshooting a 100hp recoiler motor on a metal slitter machine that constantly blows line and load fuses. It is on a DC drive. The drive has been replaced and the motor has been rewound. The...

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...

I've seen two different explanations on the working principle of DC motors: One considers the rotor as a loop of wire that experiences a torque because current flow is perpendicular to an external magnetic field. The other describes the loop as an electromagnet which then experiences a torque...

My project is to create a circuit for a stroller that can store the mechanical work into electrical while moving around and with the push of a switch, use the electrically stored energy to assist the movement of the stroller. I’ve tried capacitors but it ended up not being enough voltage and I...

Hi everyone, I'm trying to derive DC motor differential equations. I have some doubts: I have a viscous friction coefficient in terms of N*m*s. Is it possible to express it in terms of N*m*s/rad? And how? Some exercises show this value in Newton-meter-second and others in...

Hello everyone. I have a RC helicopter (WLtoys V912) that recently had a crash. The main board was damaged and replaced and I got it working again but there is a problem. The main brushless motor is not as powerful as before and I have to apply 75% throttle to keep hovering above the ground. It...

Hello all! I just discovered PF as I have been searching about a project I have been pondering for a day. The idea is to have a device that I can set my 3lb camera and have the device rotate left-to-right && || right-to-left over the duration of 2 hours for use in a sunset/cloud timelapse...

I need a 12v DC with appropriate torque. In my design, the axle of the motor would be pointed straight in the air and I want to affix a wheel to it and have the wheel spin flat, sort of like a pottery wheel sort of design. I know what the wheel is made of, its dimensions and approximate weight...

Hi, now I'm working on a project which involves a dc motor and high voltage. I'm developing a machine consists of a motor to rotate a platform disc and high voltage will be applied during the rotation. The problem is when I supply a positive high voltage at motor shaft during rotation, the motor...

In a DC motor as I understand it, a current is passed through a coil of wire within a magnetic field. The magnetic field exerts a force on the current perpendicular to the direction of the current. This force causes the coil to spin. Is the coil is between the north and south poles of 2 magnets...

Hi forum, I've been thinking about efficiency factors, I've read that they are more efficient at higher loads? I was wondering why this is... On the one hand at higher loads (maybe lifting a heavier mass) the rotation rate is reduced so this reduces energy losses due to friction? (so goes with...

I have doubt. Is it possible to convert DC motor to Stepper ? If yes then what is the procedure ?

Hey, I need a little help I know in a DC motor there are permanent magnet and also coil So my question is, what is the equation to calculate the magnetic field strength in a stator dc motor compound?

Hey guys I need help with my homemade DC Motor, as it doesn’t work, pic is uploaded Thanks

Homework Statement Write down the equations of motion and develop the continuous-time system. Homework Equations See my word doc. or PNG's. The Attempt at a Solution See my word doc. or PNG's. I assumed that there was no friction as no information was given. I can easily get the transfer...

Hi guys, can someone please have a look at the following problem that I am struggling with; An 8.25 kW shunt DC motor is supplied with a terminal DC voltage of 300 V. The armature resistance of the motor Ra is 0.25 ohms, and the field resistance Rf is 40 ohms. The field winding consists of 1500...