What is Dc: Definition and 1000 Discussions

Homework Statement Homework EquationsThe Attempt at a Solution For the textbook diagram of a separately excited dc motor, the voltage equation for the armature circuit is given as ##V_t=E_a + I_aR_a## But in the class notes, it says ##V_t = V_a## Firstly, I don't know if the ##V_a## refers to...

Homework Statement A machine, with an armature resistance of 0.16 ohms and K##\phi## is to drive a load that requires a torque that is proportional to its speed. One point on the mechanical torque-speed relation is 16 Nm at 400 r/min. If the armature terminal voltage is 50 V, at what...

Homework Statement A 250W 24V 1800rpm DC machine is operated as a shunt connected motor and connected to a fan that draws 60% full load current through the armature. 1) Sketch the circuit 2) The field winding requires a current of 0.8A to produce a motor EMF of 24V. Determine the field...

Hi there, I've been looking through the web for hours but I cannot find a DC drive that can do everything I have in mind. After a few hours and being thoroughly confused. I was wondering if someone on this forum would be of any help. I'm trying to buy a 0.5 HP Permanent magnet DC motor to...

I'm working on making a model car, and am trying to calculate the torque required to accelerate the car from a stop to 1.22m/s in 1 second, so I can pick out the right DC motor... The acceleration required is 1.22m/s/s (~ 4ft/s) The weight of the car is 0.85 kg The drive wheels diameters are...

Hello, I need to buy a DC motor for my project work. My project involves rotation of a cylindrical disk of 1 kg, inside water (approx. 2 cm below the water level) at different speed ranging between 100 rpm -200 rpm. For this purpose I need to buy a DC motor but I am not sure of what...

I need advice on assembling a pulsed dc electromagnet. I'd like to experiment with eddy current levitation. I've seen educational videos where a pulsed DC electromagnet will generate eddy currents in a plate of aluminum, which creates is own magnetic field, and causes the plate to levitate due...

I have a confusion about the rotation of dc series motor..Suppose I put some load on it and turned it on..Due to no initial back emf, high current will flow in the armature (and field) and due to high starting torque, the motor will start rotating at say,1000 rpm. This will induce back emf which...

I know 2 simple ways to convert AC into DC: Wheatestone bridge with diode is one the other is increasing the number of loops in magnetic field in DC power generation. Is there a simple way to convert DC into AC? I suppose a motor could spin a loop of wire without a commutator in a magnetic...

I am having confusion about the no load and full load speeds of a dc motor. What exactly does 'loading' stand for? How do we change the loading of a dc motor ?What is the relationship between loading and the speed of the motor? Which situations does no load and full load refer to?

Hi, I'm doing research for my science project. I chose Wind energy and I need to learn a few things about DC Motors, Who is a good manufacturer for 6-9V .5 amps DC motor/generators? What happens if the generator goes over the recommended RPMs? How do you keep the RPMs between the minimum...

Here is the problem: I have already lost the ability to get the correct answer for AI Homework Statement (a) What is the maximum potential difference that can be applied to the terminals a and b? 33.541 Which resistor will have the largest current? V (b) For the voltage determined in part...

Homework Statement Homework Equations [/B] Tao = R(th) C The Attempt at a Solution The unknown DC circuit model consists of a V(th) and R(th) Tao = (R(th) + 3000) C , total resistance of circuit is R(th) + 3000 0.004 = (R(th) + 3000) (1x10^-6) R(th) = 1 kOhm The V(th) should oppose the...

Homework Statement For the circuit above, draw the DC equivalent circuit. Then compute ##I_B, V_C, V_{CE}##. Homework EquationsThe Attempt at a Solution So the DC equivalent circuit was easy to draw. My concern is about the final answer. The answer given does not match the answer I've...

Hello. The skin depth is nothing but measure of penetration depth of EM Wave when it is incident on the conductor. It is well known that the skin depth is decreased when the EM wave frequency increases. But thinking about DC field. We know that when DC is applied to metal (metal is installed...

Hello, I have forgotten most of the electricity physics we studied and I have problem describing/understanding a concept. Does AC current produce less loss than a DC current? I found this statement in a website: "AC electricity loses less power over power lines than DC"...

Hey all, me and my friend are attempting to control a 5v dc motor and make a LED blink simultaneously using a H-Bridge Motor Driver 1A - SN754410 and ATMEGA328 micro-controller(16mhz, 8bit). The issue is is that when my H-Bridge activates the motor using input from the micro-controller then the...

Hi, thank you for your help in advance. I have a circuit configured as shown in this image. I got this arrangement from an earlier thread. An arduino controls a DC solid state relay, and it works fine when my load is a simple LED. The arduino is controlling through a digital output header and...

Hello, I am wondering where a good article may be discussing the theory behind DC arc fault detection for PV systems. Seems most articles are based on detection for AC circuits. Trying to have a better understanding for troubleshooting purposes.

Hi, I'm new here so I'm not sure how things work but I'd like some help on a question. How do I go about finding an expression for both i_in(wt) and the average current? This is the inductive rectifier circuit I'm working with. http://i.imgur.com/HaWzFfQ.png http://i.imgur.com/kefMiOd.png...

hi! when I send a square wave to a digital oscilloscope it detects the signal + dc signal. I wanted to know why. I was thinking about internal resistance of coaxial cable i was using. signal got out of an oscilloscope/wave generator and in channel A of the same oscilloscope/wg. It was +-1...

I understand that from KVL e = v -IaRa e=k(flux)speed speed=(constant)*(V-IaRa)/flux But physically what causes the speed to increase? What force causes the rotor to accelerate? In fact physically, the rotor is moving because of field flux interacting with armature current's flux. So...

Homework Statement [Picture of Problem](http://i.imgur.com/7q4yj8O.png) Homework Equations [/B] * It is dealing with drawing the DC model of a circuit * Now i know when drawing a DC Model, all capacitors are open (or ground) and AC sources are grounded as well. * In this specific problem, i...

How does a stun gun or a fly swatter circuit produce DC voltages that are at least 2 or 3 orders of magnitude higher than the single 9 volt DC battery used to power the device. I would appreaciate if someone can give me some information regarding the sort of components/circuits that are used to...

In case of dc motors , w eknow that ..we have a supply which supplies a current which divides into armature & field current for shunt motor...& the field current generates flux which links the armature winding & emf is induced.. but here I want to know the role of armature current .! Armature...

Hi everyone, my question is related to producing a magnetic field from an array of straight parallel wires. In my scenario, imagine the wires as being stacked into a regular array similar to the way a pile of lumber is usually stacked, so that the ends are exposed, eg: ====================...

Can I say that energy transmitted in DC by electrons flow like ants walking align and in AC by electron vibration like water wave ?

Hi! I want to design DC power supply 12V 2A. Here is what I have done. Firstly, we need to transform AC main voltage. I will use transformer with ratio Np:Ns=16:1 : We must choose diodes with maximum forward current more than 2 amperes. I will choose UG8JTHE3/45.. This diode has maximum...

Hey Given the simple electric circuit below, the connection between the negative end of the DC source and the load (R1) is a pipe where heavy oil flow with some H2S and CO2. The pipe is made of iron and copper alloy. Without the DC current, H2S and CO2 will corrode the pipe. After introducing...

which motor driver ic is to be used to interface 4 dc motors in a RC car? And how is the interfacing done?

Hi, I would like to know what happens to the flow of DC current and voltage in an inductor if we change the reluctance of the inductor core repeateadly, Just a DC power source attached to an inductor in series with a lightbulb for example , now as the DC pass through the wire wound around the...

Homework Statement A locked rotor test is performed on a permanent magnet DC machine with the following results: Terminal Voltage 5 V DC Input Current 10 A DC Locked rotor torque. 20 Nm a) Making suitable approximations deduce the effective rotor resistance in ohms? b) Making suitable...

I am currently trying to drive a DC brushed motor, but its specs are unique enough that I haven't been able to find a suitable driver. I found one that almost fits our application but our amperage is closer to the peak then the continuous. So is it possible that I could put two of the same speed...

Homework Statement Find I1 , I2 and I3 Homework Equations I = E / R I3 = I1 - I2 The Attempt at a Solution its the trouble with parallel different emf . I know a formula how to combine them into one but it needs inner resistance . i don't know how to do it with the ideal circuit . The...

Homework Statement I performed a lab with a simple DC circuit. The circuit has 4 resistors (i.e. R1, R2, R3 and R4), which is the same as shown in the attached image. When the voltages across all resistors were added, they were higher than the source. How is this possible? The KVL rule states...

First off, I am sorry this post doesn't match the template guideline. I didnt realize that it was mandatory until I went to post this. I tried resetting it to get the template back, but it just restores my post. I am not understanding this topic whatsoever. We used an oscilloscope to measure...

I am trying to drive a 115V DC brushed motor with a DC power supply. Most drivers I've found are for AC to DC and the 115V supply seems to be to much for most DC to DC. Has anybody worked with driving motors with large DC power supplies? Or does anybody now where I might find one? Thanks...

Good day. I was wondering if anyone could help me with the following problem. As you can see in the diagram below, I want to set up a circuit with 4 DC Motors in parallel, each with a push button switch. And a variable resistor to control the speed manually. I would like a LED strip to be...

I wasn't sure whether to post this here or in the 'homework' section... technically it is not a homework question, but I will be happy to move it... I am really struggling with this circuit: :'( At the moment, I have no clue what to do for part i). I am sure that I will get part ii)...

I simply wanted to know, whether we can store AC power like DC?

Homework Statement It can be shown that a square wave can be represented by a sum of sine waves as given by the formula below v = v0sinωot + v1sinω1t + v2sinω2t + v3sinω3t +... Solar cells have an output that is dc. The pd across a cell depends on the incident radiation and the efficiency of...

I have only just found out about inductors, and am trying to figure out how a circuit with an inductor and a capacitor could change dc current to ac current. With the set up of the circuit, would it suffice just to have the dc supply with a 'gate' that stops/allows through the dc current with a...

Hi, I have a 300-400w wind turbine which generates 3-Phase AC @ 12v 33.33Amps Maximum. The wires are colour coded Red, Black, Blue. I have a 3-Phase AC to DC rectifier which can handle up to 1200v @ 50A. Currently I have it connected like so; Red, Blue, Black. I'm wondering, does it matter...

Yes I now a DC motor is for DC (lol) but I don't understand why do they change rotation 50-60 times per second (vibrate) when connected to AC, I though that, like AC or Universal motors, the alternating current would "replace" the commutator? Thank you :)

my friend gave a dc supply to a transformer in my college lab accidentally and the fuse went off can i get an explanation on why this happened?

sir, i am looking for fixed DC (110VDC and 220VDC) from my variable AC source (0 to 220V). please support me. rajesh.p 9010770003.

Is ohm's law (V=IR) works for both AC and DC. PLz explain in details Also let me know which formula is right for power calculation for AC and DC circuits. (P=VI or P=VICos)

Hi everyone, I have implemented PI control of speed of a PMDC motor under no load condition. I now intend to implement the same with a load added to it. I want to compare the results with simulation as well. Is there any way of adding a known load to a DC motor. In my set up the dc motor is...

I was walking around at work today to find an AC amp Gauge on a DC breaker (1000KW, 250 VDC), Which made me scratch my head if there is any difference between the two gauges for this application? Any idea? Thanks.

Hi, I want to connect multiple small dc generators in series to increase the power , it is possible ? What are the problems that i might face while doing it ?