Transformers Definition and 254 Threads

Along the same lines of connecting two transformer in series, Suppose the first transformer is a neon transformer with an output of 15KV, and the second transformer is a home-built built to handle 15KV on the input, and 15MV output. The problem remains, how do you couple a high impedance...

I have a uniquie project I am working on and was wondering if someone could tell me how it would be possible to control a mechanism using my current controller. Right now I have a differential temperature controller that uses two sensor probes and turns on and off a 120V relay switch if the...

Well we can make a three-phase transformer using THREE single-phase transformers, but is it possible to make one, using only TWO single-phase transformers?

Homework Statement Consider the motor arrangement shown, Assume ideal transformers and lossless transmission lines. The start capacitor shown in series with the motor is only used to start the motor, and is then shorted out of the circuit. The motor is loaded such that it delivers 5hp, and...

Homework Statement [PLAIN]http://img192.imageshack.us/img192/8428/circuits.png Homework Equations \frac{V_L}{V_s} = \frac{nR_L}{n^2 R_s + R_L} R_s = \frac{R_L}{n^2} P = \frac{V_L^2}{R_L} The Attempt at a Solution How should I go about solving this problem? Do I have to...

hi guys, i was studying on transformers losses, i need help in some problems. why open-circuit test show only excitation losses and not i2R losses.. thanks...

Hi, I'm new here, but to the point!I'm currently designing a system that I'm utilizing a series of 6 volt microchips to control. I have about 40 microchips at my disposal. that are C programmable , have a very good memory and all, multiple I/Os. And they have timers and oscillator systems and...

I have two transformers of rating 500 KVA. Power supply avaiable is 11 KV. what size of HT cable should I use?

1. when an alternating voltage is applied across the primary coil, an emf is induced in the secondary coil 2. when an alternating voltage is applied across the primary coil, an alternating current is induced in the secondary coilcan anyone tell me which one is true and why? Thanks a lot.

Homework Statement In our lab about transformers we have a question as follows: Consider a loop in a uniform magnetic field. If the field is suddenly turned off, in which direction will the current flow in the wire? Homework Equations The Attempt at a Solution My first thought...

Homework Statement A simple transformer with negligable looses has a primary coil of 2000 turns and a secondary coil of 150 turns. if an AC current of 240Vrms is applied to the primary, calculate the secondary and primary currents if the secondary is connected across a resistor of 300 ohms...

dear all, can you please suggest the size of the earthing transformer i should be using on HV for a 5MVA, 11KV Trasformer?? thnx DPV

I know step up transformers decrease power loss by the electrical cables, but I'm not quite sure how this works... From what I understand, step up transformers increase voltage, hence decrease current, which means less power is dissipated by the cables since P=(I^2)R. But then couldn't you...

Hi to all is it possible to use the same transformer in the range of KHZ on the one hand and on the other the same one for MHZ? thanks a lot

Can anyone give me a source where i ca completely ready about the electrical phenomenon in transformers like the terminology, single phase , 3 phase transformers and then torque and mef production ?? a textbook was prescribed to us in college but it really contains a lot of mistakes and makes...

I don't even know where to start! anyone got any ideas? A transformer having a 2:1 turns ratio is considered to have a primary resistance and reactance of 1ohm and 2ohm respectively, and a secondary resistance and inductance of 1ohm and 6.37mH respectively. Magnetising current for this...

how can i connect 2 transformers in series and what is there equivlent turn ratio ?

Homework Statement Hey PF! I had a problem that was bugging my mind. We know that in any circuit, the total resistance has to equal the total voltage divided by the total current, right? That is, R=V/I. And we also know that when you have a step up or step down transformer, power is conserved...

i never heard of such a thing but what could be the circuit analysis to this? http://i.imgur.com/Zd6qn.jpg what is V1 and V2? what could make V1 and V2 not equal?

I am confused from a couple of diagrams I have about how to correctly wire 3 small transformers to form a delta wye connection. The transformers are labeled as Primary H1 H2, H1 H2, H1 H2 Secondary X2 X1, X2 X1, X2 X1 My question is in all the diagrams I have the Delta connections...

Hi, so I have been having sleepless nights about this concept. From what I understand, say a typical power generating plant that produces 2000MW of energy, for example, will want to transmit as much of 2000 MW of power to the grid as possible and they do so by stepping up the voltages to...

Before a few days ago I always thought that when transformers decrease the voltage, the transformers increase the current. Then on another thread at Physics Forums, people have told me that when transformers decrease voltage, they don't increase the current. The PFers told me that the...

Hey guys, i cannot make heads or tails of the concept of "Transformer Polarity". Tried looking for the material on the web but still couldn't get it. So, please help me out with dot polarity! Thanks

my professor gave us a 30v power supply using a center tapped transformer and wanted us to simulate it in pspice. He told us to use the k linear function to connect inductors together. The problem is that I got it to work, but when I simulate it I get something that I don't know that I am...

Well the next step in my coilgun is a decent power source i every camera circuit that i use is burned up so i thought that i use a transformer well a audio transformer as the voltage multiplier but i can't seem to wire it right it actually doesn't charge the capacitors so i was wondering if it...

This is a problem I stumbled upon after noticing a pattern in the lab- the measured current was never quite what you'd expect from the turns ratio of either transformer alone, but somewhere in the middle. I used 50:5 nominal turn toroidal CTs with 15 turns in one CT primary and 5 turns in...

Homework Statement You need a transformer to reduce a voltage of 150 V in the primary circuit to 25 V in the secondary circuit. The primary circuit has 130 windings and the secondary circuit is completed through a 55 ? resistor. (a) How many windings should the secondary circuit contain? (b)...

Hello friends What is the use of 1:1 transformer and are they using currently in hi-tech circuits. thanks

Based on Maxwell's equations, a physicist suggests that there should be a way to have a transformer to step-up or step-down gravity: http://www.technologyreview.com/blog/arxiv/25407/ What could such a gravitomagnetic transformer look like in nature?

So I've been confused about transformers lately. In searching for some information regarding the basic transformer, I came across this: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/transf.html#c1. While this page was informative, I am still left confused in regards to one point in...

Hi physics gurus Homework Statement What should the primary voltage be changed to in order to produce a secondary current of 10 A, given that the V / I ratios for the coils do not change? Current ratios that I have calculated so far are as follows: Np (200) Vp (1200) Is (15)...

1.[SIZE="4"] Lets say I put a resistor with a value 1 ohm on the secondary side.. what happens? [PLAIN]http://img256.imageshack.us/img256/9639/67417248.jpg The thing is, in theory I just calculate the Z value and find out what it is. BUT, why does it have to be that. Practically, what would...

Homework Statement Three single phase transformers rated 100kVA, 13.2kV/2.4KV are connected in wye-delta on a 3-phase, 18kV line. I need to find the maximum load that can be connected to the transformer bank and the outgoing line voltage. Homework Equations The Attempt at a...

My question is if you connect multiple transformers together with the secondaries in parallel, how do you calculate the sum current from the transformers. Is the current calculated by dividing the voltage on the secondary winding by the impedance of the secondary windings. Or is it based on the...

I need to know the purpose of using different numbers of coil turns for the primary and secondary coils on a transformer, provided the turns ratio remains constant. Put into context, what is the difference between a transformer with 10 turns on the primary, 20 turns on the secondary and a...

Hi, I've been a bit confused with how the equation Vp/Vs = Np/Ns came about. From reading a physics textbook, I understand that the voltages came from the emfs ε (primary) and ε (secondary). The primary voltage through the primary coils causes a change in magnetic flux which induces an emf...

hi guys, I want to know if it is always possible to link two transformers in series with different rated voltage. And if there is any concern about the polarity. If it is not possible in which conditions it can be done?

This is a question written in my book, i tried to solve it but didnt work with me. Homework Statement A power station delivers a power of 150kW to small town at 15km from the station. Energy is transmitted by means of a transmission line of total resistance of 0.6 _()_ (ohm). The power...

Homework Statement An electric power plant generates electricity @ 22 kV and 100 A. The voltage is stepped up to 240 kV before being transmitted to a city 15 km away over a copper wire that has a radius of 2 mm. Energy is lost in heating the wire during transmission. If the transformer...

Why transformers hum? I have heard two versions. Oxygen has unpaired electrons and it reacts to changing magnetic field. Material that transformer is made of vibrates in changing magnetic field. Both explanations tell that something vibrates in a magnetic field, but what it is?

Apparently my modern electronic home electric meter uses a 'current transformer' to measure the current in order to calculate the wattage I am using. My question: is the flux generated in the current transformer also proportional to the reactive part of the current as well as the in-phase...

In poor countries, the domestic electricity supply is inconsistent, and even though the country's standard voltage may be 220V, it is not unusual for the voltage to go quite a bit below this level, say around 150V. So normally, households buy step-up transformers, so that they can increase...

The post "Temperature rise in power transformers was locked, however there may be a simple safe answer. The post said the winding temperature was 73 deg C. 73 deg C is safe for winding temperature. If it was winding temperature RISE of 73 deg C, then there may be problems. So which was it?

Hello , I would like to ask one question. Current transformers has one of the major component in electricity but we know that per load level, VA, temperature ext accuracy of these transformers can change. CT manufacturers gives accuracy diagrams for different load levels from %5 load to full...

A transformer consists of a conductor (often times can be an iron core), which is used to transfer current/voltage from one circuit (sometimes power lines) to another circuit (homes- often referred to as "stepping down"). This is done by taking a wire connected to the first circuit and wrapping...

I am hoping to use a overload relay I have rated at a low amperage to protect a higher amperage circuit. I plan to use 100/5 current transformers and connect them to the line/load terminals of the overload relay. The trip rating will be at 4 amps through the ct circuit but will have a time...

Okay, now this may sound ridiculously stupid, but I know next to nothing about transformers and so I have a question: Does the input current on a transformer have to match the rated output in order to get that output? (i.e. A trans rated 5 amps putting out the full rated current on only...

If tap changers are on auto and the harmonics are filtered out, what would happen if the tap changers are switched to manual i.e. harmonics/noise

Good afternoon! To build a serial connection of two transformers, four coils are used: Two of this coils have n1 turning, two of them have n2 turnings. The coils are built together in the way, you can see on this picture: http://img197.imageshack.us/img197/2698/transformer.jpg The...

If a transformer with coil ratios 2:1 creates a voltage twice that of the primary in the secondary coil why is the current halved? I realize that this is a consequence of the conservation of energy, but there must be a physical reason behind this. What is causing the additional impedance that...