Dc Definition and 1000 Threads

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...

I've been told that the 1/f noise for DC voltmeters is a problem when they measure a very low voltage (i.e. around 1 nV). Some readings can take weeks or even months. However, a DC voltmeter would have no problem to return a stable reading of a simple resistive circuit, of the order of the volt...

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...

I see that DC power supply have voltage between it's + & - and its 24V. However, there is no voltage with ground. I don't understand - if device's "point" has some potential, why doesn't it give some voltage with ground (which has ~0 potential) I tried this with phoenix contact...

Hi all Trying to carry out an experiment and need a high voltage supply Looking for say upto 40kv dc adjustable generator been looking on the net and only able to find low cost voltage boosters on eBay Or if anyone know of a good website to try Any help would be much apreciated Thanks...Niki

I am curious what happens if you draw DC power to a load, but as it approaches the load you chop the load connection say with a SSR or switch. The power will be traveling near the speed of light, following the wire toward the load. When the load is chopped by a switch just before the pulse...

Why is it preferred to use a clamper circuit rather than a DC source to shift an AC source upwards on a voltage-time graph?Both require a battery(DC source) so isn't it cheaper than having to use some extra elements like capacitors and diodes?

Homework Statement Homework Equations - The Attempt at a Solution Here's my work : When I add the DC current source , it shows a red dotted line and won't connect to other elements . Any help would be greatly appreciated !

Hi! I learned that all or at least majority DC voltage regulators such as step down module work by interrupting DC at some intervals. However, if I am interested in continuous DC, is it possible to make such voltage regulator that doesn't interrupt voltage at given intervals? Or what would...

Hello, I was reading an electronics book which state that transistors work with DC signals only (not AC), suggesting that relays are needed to switch AC signals. Is that a mistake? When used for amplification, I have seen transistors amplifying time-varying signals (which means AC). Unless...

What solutions are there to feeding a high DC voltage rated (eg 1000VDC) certified grid tied solar inverter such as a Yaskawa Solectria PVI23-480; from an alternate DC+ bus supply. For instance the 670 VDC input from a solar string; might be replaced by a a 6 pulse rectifier; (possibly from a...

Hey, so for a capstone project we are working with 2 24V wheel chair motors. and the sponsor wants us to make it operate like a skid steer (two separate handles, one for each motor, controlling the forward and reverse speeds). Me and my group being a mechanical engineers, we are not so...

Hi, I would like some assistance with a DC to DC boost converter that isn't powering the load I require. The boost converter is one I purchased online. It is a DROK numerical control regulator, 900 watt boost converter. Boost converter specs Input voltage DC 8-60 volts Input current DC 0-15...

I have an AC to DC voltage doubler circuit. I am using a full wave bridge rectifier that uses two diodes and two capacitors that are 470uFarad each. My supply is a 50 watt transformer that outputs 13.9 volts and 3.790 amps. The supply frequency is 60 hz. The output frequency is 120 hz from the...

In the case of a d.c. generator, if V=E–IaRa when current flows through the armature, why does V = E at no load? Why does the resistance element become disregarded at no load? Is this because the resistance can't cause the voltage to drop at no load?

Hello, Basically, I use a portable electric space heater to keep my room warm during the winter, and it works quite well, except it makes a very loud hum that keeps me awake, so my options right now are poor sleep due to hum or having my room drop to about 12 C over night if I turn the heater...

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...

Hello, for a project I need to select a motor which can rotate at 600 RPM with 3 HP of power. Do AC motors typically require a controller and drive? For example, I am interested in purchasing this. Do I need to buy an expensive controller just to operate it? How complex is the set up and...

Hello, I have a very specific problem and didn't find any way to solve it. My signal is very slow changing at 5V +-100mV When I want to display this signal on my RIGOL Oscilloscope, the problem is, that with AC-mode I don't see those slow changes and in DC-mode the offset range is limited to...

This thought experiment has been bugging me for a very long time - I'm hoping someone can help me understand it. Premise: - Simple DC electrical circuit consisting of a battery, wire, light bulb, and another wire to complete the circuit. - Each wire has a length of 1 light-year (yes, very...

Hi, I have a graduate level understanding of power electronics. The other day I decided I wanted to series the output of two DC Boost converters. I remembered the simple conceptual circuit of how they worked, and I jumped onto google to see if this could be done safely. What I read was that it...

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?

I want to make a dc generator and not sure my design will work. I will wind the coil on a donut shape disk and put 6 rectangular magnets on a disk rotor with North Pole face the coil. Please see attached pictures. Will this design works or have problems? Can I have one continuous coil or I...

Hi I am looking to purchase a Low RPM, Very efficient DC motor/Generator between 200w and 1kw for a low friction fly wheel project which involves powering up a 10kg flywheel to about 50 RPM over say 30 seconds then recovering the energy back through the motor/Generator with minimal losses...

I have a very basic question for the professionals here, but I am having a small issue with my parallel LC circuit. I have an inductor that is 6.425mH, a capacitor that is 217uF (it is two 470uF aluminum electrolytic caps connected in series to make one non-polar 217uF cap). I am supplying the...

Using as an example a 12v pump typical of aquarium, to regulate flow is better to use a potentiometer or a closing valve to affect a rate of flow?

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...

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...

Is anyone attending the AAPT SU18 conference in Washington, DC? I am, and I have signed up for the LabEscape (I guess we need to solve a mystery to 'escape from the lab'), but need 6 people in the group to play this game. If you are going and interested in taking part in this cool puzzle game...

I am currently working on a module for the practical application of DC bridges. The particular problem I have at the minute involve "show that" questions. The first question is in 3 parts and reads as follows: - A Varley Bridge is connected to a faulty three core copper cable by two identical...

I wanted to remove the dc component from a signal but i can't use the average method because i have only a half cycle sampled not a full cycle . Is there any algorithm or method that can remove the dc component using only a half cycle? (The signal is sin(x)+2*sin (2x) +3*cos (3x)+4*cos (4x) +5...

Is there some common parameter for DC power supplies that provides the maximum oscillation amplitude allowable at the output? For some context - I would like to generate an oscillating signal powered by a DC power supply, but to prevent most of the oscillations reaching the DC supply I am going...

Homework Statement It’s a rather confusing circuit, I’m having problems trying to understand the way current circulates through the circuit. Homework Equations Kirchoff’s DC circuits laws only, no resistive simplification neither nodal analysis The Attempt at a Solution I’ll attach my intent...

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...

Comic is Superman/Batman #80 Superman explains that virtual particles are always spontaneous generated And that he's using his heat vision to (excite) the vacuum in order to accelerate the process. He's generating more virtual particles So my question is, how much energy or heat did...

I am searching for a legible schematic diagram for a Tenma 705-72 DC laboratory power supply. Each of its two channels uses a LM723 regulator and a pair of 2N3055 power transistors. One of the channels operates normally; the second channel puts out the maximum voltage (37 volts). Any help...

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

Homework Statement AC production and relationships that determine movement and current flow direction from Flaming's left hand and right hand rule. Homework EquationsThe Attempt at a Solution Left hand rule for motors- right hand rule for generators The thumb, index and midle fingers are all...

I am wondering whether electrons have a net motion against an applied constant electric field in a conductor. Intuition tells me that "of course they should", but so far the math has shown me otherwise. Here are my current thoughts: 1) I cannot rely on the obsolute Drude's model. What's more...

Homework Statement why is there a loss of energy in DC circuits and power loss is reduced in AC when transmitted Homework EquationsThe Attempt at a Solution Loss of energy in a DC circuit is due to the resistance of the wire cauing the wire to heat up therefore energy is being lost by heat...

Homework Statement similarities and differences of AC and DC current in simple circuits. Outline using diagrams and a clear desciption the loss of energy in DC circuits and power loss reduction of AC when transmitted. Homework Equations N/A The Attempt at a Solution DC loses energy over long...

Here is a longish article from Science mag news about using an agent based modeling approach and detailed geographic information to model what might happen if a small nuclear bomb went off in the middle of Washington DC. The article also discusses the use of similar models for other purposes...

Setting up a test stand that will need a controller to cycles a device ON and OFF at an adjustable time interval (allows me to make the ON duration and OFF duration whatever I want). It will also need to keep a count, so I can track the cycles count and also set a limit on cycles so it will stop...

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?

Hi, I have a question about ac component and dc component of a source. For example, there is a current source connected directly to a resistor. If the current source supplies a sine wave with no dc offset, then I understand that power supplied by dc component is zero, and so power absorbed by...

The way I understand most generators that are used in plants is that they take the heat form combustion or fission and use It to create steam to run a turbine with magnets on it that create AC power over a coil. how could a dc generator work?

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

Hi suppose you have a conducting liquid in a strong magnetic field, and this is pumped in a continuous loop through two electrodes, why does this produce a D.C current? My thinking is a simple answer, and that is that the D.C current is produce because the fluid is moving in one direction...

Hi all, I think this issue periodically resurfaces in PF. I have found a similar discussion in this closed post and possibly others. I'm posting this because I'd like to check my understanding, if anyone is available to provide some furtherinsight. So I'm trying to gather a "overall"...

I am trying to build a Voltage Doubler to use a motorcycle 6 Volt a.c. alternator's dedicated headlight coil (which presently runs a 36W incandescent headlight bulb) to provide 12 Volt d.c. to drive a commercially-bought 12V LED headlight unit (also rated at 36W). Frequency will be (1500 ~ 5000...