Dc Definition and 1000 Threads

I have been thinking of the nature of the electric current , or the motion of electrons in a copper cable of a closed DC circuit. Recently I learned the speed of electron is very slow in the copper cable and in a AC circuit the FREE ELECTRONS are in fact moving back and forth. But in a DC...

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...

I found this schematic while watching the following video on building a DC 20kv power supply: I wanted to test the circuit in multisim, but I'm having trouble finishing it. None of the transformers available look like the one used in this schematic. Below are the transformers available on...

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...

[warning: wall power issues ahead] I had a friend send me an LED strip with a USA wall ac to 12v dc PSU, so I slapped a 3-pin wall cable on it and spliced a toggle button into it. Everything works fine buuuut... If I put my finger here (assuming it's a resistor?) I get some current, like so...

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...

Hello, I am looking for some information on how 2 different types of magnetic fields interfere with each other. And i don't mean, 2 magnets, but let me be specifically: Lets say that you have a very strong static magnetic field, from a huge magnet. (for instance, the strength of the magnet of...

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.

Hi, My main question is: should we be subtracting the rotational power losses from the motor output power in our efficiency calculation? My approach: Will skip extra work as I have done the above parts of the question correctly. I used power conservation to state that: $$ P_{input} = P_{motor}...

Hello, I want to make a choke for a AC to DC welder conversion. The welder is a 50hz single phase oil cooled unit with constant current output upto 110A. I will bridge rectify the output to give rectified AC output. I need to smooth the output and as I need a constant current output, I'll...

I have an object that will be under DC excitation in operation but will be qualified using 60 Hz AC. Because of this, I am interested in 2 simulations. 1) I would like to simulate E-field intensity representing a 60 Hz excitation. Do I need to do a transient simulation to truly get this value...

I had previously solved this using Root Mean Square method by integrating the value of voltage from t=0 to t=T/2 and then from t=T/2 to t=T.Answer was Vo/2½.Yesterday I found this question👇🏾 if I followed the previous approach then: 5 volts is not even in the option. How can I find the DC...

Induced voltage of DC motor isV=Blv where B= phi/S where S=2*pi*r*l and magnetic flux is phi=B*2*pi*r*l as shown in the picture. that leads to the equation V=PZ*phi*N/60amy question is, why do we set S=2*pi*r*l Shouldn't magnetic flux 0 because the magnetic flux of a closed surface is 0...

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 confused as I'm aware speed is directly proportional to the EMF, but is it proportional to the voltage as well? If the speed of a DC generator is halved and everything else is remaining constant the EMF will have so will the output voltage half

Hi. I am reading a textbook about simple DC generator. The situation is if we are rotating a single armature coil within a constant field B, the induced emf will be (if we are to only think about the magnitude), emf= B*l*W*omegaB = magnetic field l = length of the coil W = width of the coil...

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...

Here is a motor I bought : https://www.alibaba.com/product-detail/55kg-thrust-MP120100-brushless-motor-kits_60816322811.html?spm=a2700.12243863.0.0.2ce83e5f3D0fu9 Can anyone recommend a controller I can use for it? There's many online but I'm unsure which to choose. The motor has 3 cables and...

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...

Was just wondering if someone could take a look at my calculations and see if I've done them correctly.

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...

I see that ##V_{ac}=V_{ab}+V_{bc}##, with ##V_{ab}=I_1R_1=I_2R_2## and ##V_{bc}=I_3R_3##. However, I don't see how to express mathematically the maximum value of ##V_{ac}##. Could someone please help me with this task?

Hello, I am experimenting with DC variable power supply and want to make sure I am using it correctly. My understanding is that it can output a variable DC voltage by turning the voltage know CW. The current-limit knob, as far as I know, is only there to set the maximum current that we would...

Hey everyone, So I'm trying to figure out what could be causing this problem: I have a DEWENWILS Wireless Remote Wall Switch which takes a 12V battery 60 mAh(23A battery), when I replace the battery with a 12V 500 mA DC power supply, the unit stops working properly. I'm able to use the Power...

We are given that ##i_D = 8\cdot 10^{-12} (e^{v_D/20m} - 1)## Hence ##i_D' = e^{50 v_D}/2500000000## and ##i_D'' = e^{50 v_D}/50000000## Then I have that ##\delta i_D \approx\frac{ e^{50 v_D}}{2500000000} \cdot \delta v_D = \delta v_D / 5## Cancelling ##\delta v_D## from boh sides and solving...

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...

https://comicbook.com/startrek/2019/12/03/star-treks-d-c-fontana-dies-at-80/ https://en.wikipedia.org/wiki/D._C._Fontana

Homework Equations: E=V-IaRa n2 = (n1×E2)/E1 If = V/Rf V×Ia T∝ΦIa E∝ΦN i) V = 500v, N1 = 600RPM, It = 45A, Rf = 220Ω, Ra = 0.3Ω It = Ia + If If = V/Rf = 500/220 = 2.273A Ia = It - If = 45 - 2.273 = 42.727A Now: T∝ΦIa and if the flux per pole is constant then T∝Ia So Ia when the Torque falls...

I am getting one of those $10 WIFI units from china runs on 120 volt AC and I want it to run off of 12 volt DC car battery I am thinking will need to open up unit and try to figure out what the DC voltage is that is coming from the AC supply unit and then insert a fixed regulator of 12 or 5...

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Circuit Diagram Components USED 1. MOSFET ( 47N60C3 ) (https://www.infineon.com/dgdl/Infin...n.pdf?fileId=db3a304412b407950112b42dff93492f) 2. Primary Transformer Coil 3.12V. 2A Switching Power Supply 4.function generator ( currently using 66kHz frequency) 5.oscilloscope 6. Schottky Diode (...

For one of my scientific projects, I want to charge a couple of 450V capacitors in parallel, which I get the power from household electricity, because a lot of lithium polymer batteries can be expensive and take up a lot of space. The problem is, the power supply gives a 250V AC, and and I need...

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?

Summary: Hi there On a 12VDC transformer we use at school. Is the positive terminal +6V above ground potential and the negative terminal -6V below ground potential? Thank You Hi there On a 12VDC transformer we use at school. Is the positive terminal +6V above ground potential and the negative...

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...

Summary: Can a rotating AC Magnetic field induce movement in a static DC Magnetic flux? I'm designing a control panel, and the customer has asked us to reduce the EMC as much as possible; there are no drives, or other noise creating devices, just AC circuits. I thought a good starting point...

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...

Intuitively I fell like AC would lose more power long a long power line than DC. I will use a model to explain my perspective. Let me model a wire as a long straight, non-frictionless tube, about the diameter of a marble, filled with a row of marbles that are each connected to the one next to...

I have a simple 12vdc system on a boat with a single battery bank. There is a stock alternator on the engine and I've inherited a solar panel i'd like to install. I understand that most solar charge controllers have built in back feeding prevention, but will i also need blocking diodes on the...

Are any generator that produce dc current without brushes or commutator?

What would happen to a dc small generator if it is moved at more rpm that is it designed to? Does it will produce more, less or the same? I have this question since I while. Thank you

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...

Hello all PF members! I was wondering about the power dissipated by resistor at high frequency which is: ##P=Re\left \{ U\cdot I^{*} \right \}=Re\left \{ \frac{\left |V^{+} \right |^{^{2}}}{2\left |Z_{c} \right |}\cdot (1-\left |\Gamma \right |^{2} )\right \}##, (1) where: ##Z_{c}## -...

I hope I am posting this in correct forum section. I just downloaded LTspice for my Power Electronics course. Does anyone know if the software can display the DC component of a waveform such as found by determining the Fourier series of a waveform?

So I understand that when an electric field is produced in a conductor of length L, the net electric field in the conductor will be 0 because the rearrangement of electrons in the conductor results in the production of its own electric field which cancels out the one produced initially...

Hi everyone! I'm trying to understand why when writing the differential equation of a discharging RC circuit V_C-Ri(t)=0 \to q(t)/C - Ri(t)=0 we replace i(t) with -\frac{dq(t)}{dt}. I read many threads but I don't understand the physics behind this. The usual answers I read are something like...