Dc Definition and 1000 Threads

Hello I am a EE student and was wondering if anyone had some suggestions on how to fix my inverter it's for a capstone project we are using a twelve volt battery and trying to get 120vac 60Hzs we can get 59Hzs from the curcuit intill it goes into the transformer then it changes to 177Hzs and...

DC Electric Motor Torque/Power Usage Hello Everybody, I am mid way through doing an electronic engineering degree, I fancied as a summer project to build 6 wheel search and rescue robot. Idea being to use wheel chair motors to get the thing going. The problem is I am not an mechanical...

Hello all- I'm not very keen on electricity but am hoping this question is simple enough somebody might be willing to help out. I have a device that runs on 120v ac. Inside the device, the power supply converts the current to 1 12v-, 1 12v+ and 2 5v+. I'd like to remove the AC power...

A comment in another thread led me to think about an experiment which can hopefully test the validity of the pointing vector theory for a dc current. I’m very unsure of the outcome of this experiment but what the heck. Here it goes: the Poynting theorem states E x H is power per unit surface...

According to http://www.aveox.com/DC.aspx" The way to calculate the output of a DC motor in kRPMs is the formula RPM of motor: kRPM = (V - RmI) / Kb V= Voltage Rm = Terminal Resistance I = Current Kb = Voltage Constant (V/kRPMs) This insinuates that an increase in amperage...

I am studying Electrical machine course on my engineering semester. Can you you people provide me links for animation pics or video for working of dc generator and dc motors? Thanks for your help.

I want to know the function of the two power amplifier ?

Im working on a model in SIMULINK of an electric drivetrain with an automatic transmission.. The overall goal is to develop an algorithm controlling controlling a CVT via factors such as current, angular velocity, etc. This may seem very basic to most of you, but i know that Output torque =...

Hi My introduction to Electrical Engineering is Like one hundredth of a starter But I am here to have some Help I want to Design a Pulsating DC power supply of 1K or more with micro or Nano Time constant I will highly Appreciate any kind of help and Guidance and also want to ask is...

I understand the difference between AC and DC, and i also understand how an AC transformer works... but I guess not completely. My question is why can't a DC use its emf to create a lower voltage current like AC can? Does the DC's emf accrue over time thus making its transformation short...

1) How do i Determine the total current provided by a DC supply? 2) Total Effective Resistance 3) Total Voltage Asking these questions for a friend, thanks!

The circuit is in the attachment, plus the values that I've managed to find out so far. Im having problem with figuring out the voltage at t=infinity. So far i know that when t->infinity that inductors become short circuit. It says to apply current division and then Ohm's Law as a hint, and...

Hello Forum, the formula for skin depth is both inversely proportional to conductivity and frequency omega. There seem to be 3 cases when the skin depth of a metal is exactly (or tends to) zero: 1) if an EM wave of frequency f (any frequency) is incident on a perfect metal wall (infinite...

Hi I have been using a DC HVDC converter for a project. I am a little confused with the full load and no load characteristics for this kind of converter.The user manual states that at full load "X" Volts of input gives "Y1" volts output and for no load that same input voltage gives "Y2" volts...

I am working on a project where I have a ball-screw type linear actuator being driven by a 24V variable speed DC motor. There is another 24V DC motor that drivers a pinion and ring-gear. The linear actuator controls the system's elevation and the ring gear controls the traverse. I would...

I have some confusion on how to power a 1 hp DC winch motor that is intended to run off a 12 V battery. I need to precisely control the velocity of the motor and will need a PID controller to do this. Since speed of the motor is proportional to the supply voltage, is 12 V the maximum voltage and...

Will a generic dc motor interrupt the circuit fast enough to get a ac current on the other side of the transformer. I was assuming that a motor interrupt the flow of current.This is to feed a voltage multiplier.

Or does it have a hint of alternation in it as well? I know that if AC current is "direct enough" it's considered DC current. I was wondering if DC current can also be "alternating enough", and therefor might be even considered AC current.

Homework Statement A small dc motor has the following specifications and is being considered for powering the propeller of a model boat. The propeller has the intended capability of supplying 0.1Nm of torque at 200rpm. Operating voltage = 4.5V Stall torque = 6.6*10^-3 Nm Stall current =...

Hello, in an introductory course on electricity, it is typical to use Kirchhoff's laws to write a system of equations for a complex circuit having several known emfs and resistors from which the unknown currents are then found. Is this something electrical engineers sometimes do in their work...

Hi. Does anyone knows about a DC power supply that can switch between forward bias and reverse bias automatically? For example, I start it with forward bias, after 1 minute, it will automatically switch to reverse bias, and after another 1 minute, it will automatically switch to forward bias...

Is that right to see AC as current that flows like that? (marked in red) http://img864.imageshack.us/img864/5056/10vac.jpg Whereas DC would just be a straight line. Is that right?

I need to build a micro pancake DC Motor. I actually need 32 of them connected in a line with one power supply. The motors need to be about the size of a dime. Could someone write me a how to guide on how this can be done. It is for a prototype.

Superb Old Labtech Speakers to add to my RV without 120 Volt AC The Labtech AC adapter's output is 15VDC 1000ma. Using my existing 12VDC power supply (2 - 6VDC inline Deep charge Batteries) may I boost this output to 15VDC by adding 2 ?or? 3 Duracell Rechargeable AA batteries. Duracell...

ok I am hooking a dc to ac inverter to a car battery then to a transformer that will give me 115vac then i need to convert it back to dc while still keeping the 115v but in DC how do i do this? If i use a rectifier will the current drop?

Hi Does anyone know what a 2-wire dc polarity reversing voltage signal is? I have never heard of this type of signal before. I have gone insane trying to google it but to no avail. Any sort of help will be much appreciated.

Any links or suggestions would be really helpful. I have a basic understanding about transformers, bridge rectifier & capacitor. I need help in shopping what transformer, diodes & capacitors should i buy. I tried to search online but couldn't find any. Adapter Specs IN> AC:100v-240v OUT>...

I have a question regarding the effective dc output resistance of dc power supplies. For a "good" power supply, should this internal resistance be large or small? Well, I used to think that a good power supply should have a small internal resistance, so it would maintain a constant terminal...

what is meaning of ac winding and dc winding?how it differs from each other? advanced thanks.

Hi all, First timer here I would like to understand how to work out how torque is involved when increasing shaft speed using DC motors. Say if a shaft is rotating at X rpm with an applied torque of T [N.m] and a DC motor is connected through a 1:1 gearing to connect the rotating shaft and...

I want to make a DC current (from a battery) oscillate between full voltage and zero voltage (not negative) really quickly, at least 30 Hz. I tried using an electromechanical switch, but the current from the battery is too low to produce any appreciable electromagnetism, so the switch didn't...

NEED HELP ASAP! Wheatstone bridge and DC series/parallel ! Please look! I have three problems I need help solving. Problem #1: Fine the value R1 in the figure if R2 = 30ohm, I = 0.5A and V = 10V My try was: Rp = R1 + R2 , 20 = R1 + 30 , R1 = -10? ** please look for...

3-pin (Gas Discharge Tube) Surge arrester rating "DC spark over voltage" Could someone please help with a question about Gas Discharge tube, surge arresters rating? I am looking at a public address audio equipment which uses a 100vrms audio lines driven from a audio transformer. Currently...

I'm a mechanical engineer selecting a DC motor. I have the values for rated continuous operation, but I would like to have a ball-park figure for "almost" peak power consumed (which can only be sustained for a few seconds). I realize that absolute Peak Torque is when the motor is stalled. For...

Greetings E.E. Gurus! I'm a noobie in need of your guidance! Here's the situation: I have a 5V DC, 0.25 amp (1.25W ?) power source from an oil pressure switch wire on an old truck that is activated only when the engine is running. My goal is to activate a 12V DC, 2.5 amp, 30/40W...

HI all, first time poster. What I'm looking to do is isolate a 9VDC load. Specifically, I've got a 9v battery supply, and need to isolate one of the loads(200ma max). My best guess is to somehow turn it into an AC voltage, run it through a 1:1 toroidal transformer, then rectify it back to...

A while ago I built a pc board that serves as a 3 channel SS relay. The output thyristors are 25A. This circuit uses a zero cross opto coupler to fire the thyristor and turn it off (DigiKey MOC3042). I've used many of these to control aa AC wash machine motor (on/off). The first question is if I...

Hi everyone. This is my first time trying this. So please be gentle. My question is to do with a dc motor. I want to build a wind generator and I am trying to figure out what size motor to start with and try to size the blades to get the best out of it. I know that their is a lot of other...

Hello, I have this old Nintendo AC 220 V to 24 V 550 mA DC. it has this one full line followed below with dotted ones. Can you help me read this? And how do these adapters behave. Do they ALWAYS give 550 mA, no matter how much voltage drop is connected to the end? I am thinking...

Just a short question. As part of a dyno project, I am coupling two dc motors together with a timing belt. To allow the same rig to be used for different test motors, I am considering mounting this (test) motor on a table, which can be positioned in two directions on leadscrews. This would...

Homework Statement Why is the following situation impossible? A battery has an emf of E = 9.2V and an internal resistance of r = 1.2 ohms. A resistance R is connected across the battery and extracts from it a power of P = 21.2W. Homework Equations My book gives these equations throughout the...

So here is what I am trying to accomplish. I am trying to take an old Jacobs wind turbine controller that was designed for a grid tie application and make it off grid. There is a 3 phase "wild" ac input from the turbine that is rectifyed but not clipped by the internal SCR's to variable DC...

I have a DC power source and 2 LED's. I know they are polarized and only work with the current running one way. I need to swtich between the two electrodes but I am not sure how to design a circuit using a DC source that will switch back and forth at a defined rate. Can anyone suggest either...

Hi all, I am new here as i want to ask something about an engineering project i am working on. I need a motor to rotate a 200 grams cylinder which will be hanging from the motor's shaft (vertically). I wanted less than 100 rpm so the motor I chose is a 2.1W 6V DC motor with a 50:1 reductor...

In the RC circuit shown, the resistance R, the Capacitance C, and the emf of the battery are all given quantities. The battery does not have internal resistance and the capacitor is fully charged after the switch is closed. Prove analytically that, regardless the values of R and C, exactly 50%...

I am in the early stages of the design of a telescope mount and I need a control motor. I am hoping to run it on a battery so I think a DC motor is the way to go, but I need to be able to keep the rotation speed extremely constant for photographic purposes. So, to my question: Does anyone...

Hi I am a 4Th year design engineering student and have a final project to complete but my knowledge base is mainly mechanical and materials but I have to complete and electronics part of the project. My problem is I need to control 2 12V DC motors off 1 12V battery and I believe they need...

I'm currently in the process of building this project: http://www.serasidis.gr/circuits/AVR_oscilloscope/avr_oscilloscope.htm Here's the schematic: http://www.serasidis.gr/circuits/AVR_oscilloscope/images/SCHEMATIC.GIF I was wondering if it would be possible to power it with a 9.6...

Hey guys, I'm new to this site, and am a university student studying Electrical and Electronics engineering. I just completed a design project controlling a BLDC motor (pretty low powered at 60V, and giving output rpm of about 6000rpm). Now I had an idea where instead of using a single BLDCM...

Hey everyone. I'm a beginner when it comes to making stuff with motors and batteries. Could anyone give me a link or a very good explanation on how to wire a 9 volt DC motor to 2 9V batteries (that are supposed to be wired in parallel) to power a propeller? I have the motors and the batteries...