Transformers Definition and 255 Threads

If i have a transformer, and i need to calculate the core losses using this approximate equivalent circuit, according to the lectures ( taking an introduction to electrical machines course in college) the Pc ( power lost in core) = (V1)^2/Gc, but the professor clearly stated that the core losses...

Please help! I have recently completed an experiment on transformers, using a step up transformer. I am aware of all the theory that shows that in a step up transformer, the induced voltage should increase and the induced current should decrease. However, in my experiment, my hypothesis is not...

So I did an experiment a this week on the relationship between two tightly wrapped coils with same length and number of coils in a transformer. This was in a compete circuit using AC currents. I measured the Voltage, keeping the currents the same. One experiment had an iron core between the two...

I Have a Dumb Question. If Electricity Supplied from Substation to Feeder to Transformer and Under Transformer If There Are Many Consumers. Assuming That many Consumers Went on for a Holiday, Does Utility Still Pay for the Electricity to the Generation company for the Electricity they Supplied...

Hey, I'm currently working a problem that looks like this: There's more to this problem, but I'm sure I can solve the rest of it, there are just things I'm uncertain about. Actually, it's only one thing I'm uncertain about. I'm looking through my notes, and when converting the voltage...

Homework Statement Homework Equations Z_Impedance = Z_Load / n^2The Attempt at a Solution Hello everyone, I understand that in order to provide maximum power to load, the load resistance (R_L) has to match the source resistance R_S. My main confusion is from the question itself on what my...

Hi pf, Could someone please explain to me why the back emf on the primary caused by eddy currents does not result in power loss. From what I have been reading about transformers eddy currents have two effects: 1) Producing heat (P=I^2R) 2) Producing a flux which opposes the primary flux I am...

I read here: http://static.schneider-electric.us/docs/Motor%20Control/AC%20Drives/8803PD9402.pdf that harmonics cause stray flux losses in transformers, how is this so? Thanks

I worked for the Public Utilities company last summer, and we were tasked with taking inventory around the entire city, of all the transformers. We wrote down as much info as we could about the transformers, including Serial Number and whether or not it contained PCP's. From what I understood...

How can a transformer increase the voltage yet lower the current? Are the equations P=VI and V=RI contradictory? Thanks in advance and sorry if I made any english mistakes.

Hey guys, how are you? I just have an idea but can't figure it out how to solve it. Is it possible to generate electrical energy from a (high power) transformer vibration using piezoelectrics?

From my understanding, transformers allow electricity to travel long distances with minimal energy loss because they initially use a step-up transformer which reduces the current (which reduces the heat loss and hence energy loss). However, I do not understand how a step-up transformer manages...

Hi, i was looking for the Energy conversion efficiency of my circuit in Ltspice, but i find out that my Transformers is giving me strange power values i mean with K = 1 the P1 should be equel to P2 but in my case P2 is is way too small , i get equality 90% only if get rid of the Flyback...

Hello. If we assume an ideal transformer, why do we use a.c current in a transformer? I've searched and answers are that we need a changing electric current to produce a change in magnetic flux, using Ampere's law. However, Faraday's law states that a voltage produced a changing magnetic flux...

Homework Statement The problem is in the thumbnail Homework Equations None The Attempt at a Solution I just wanted to double check my answer on this: Left side of the coil is North Right side of the coil is South The arrows that indicate the direction of the current should be facing up in...

In Megger testing distribution transformers, how much importance is there in including the LV/HV bushings in the test. If you disconnect and have high readings independant of the bushing, and then put the bushings back into the circuit and the readings fall dramatically, what is that saying...

And I mean from the G1 days to present times. I grew up on G1, liked the Beast Wars. Love TF Prime and the Cybertron series games. Plus the new IDW comics are great.

Homework Statement Please see the picture attached. Homework EquationsThe Attempt at a Solution I was able to solve part A correctly, at least I believe I was able to do so. I'm struggling with part (b) however. I'm not sure were to start on this. My test that has this problem doesn't have...

How common are piezoelectric transformers in computer LCDs?

As far as i understand the thing that matter in all of the process of mutual inductance is the rate of change of the current in the primary coil $$\frac{dI}{dt}$$ butting soft iron core will increase the density of the magnetic field inside the primary coil, but how this will effect...

The question is the following: a) Determine all load voltages and currents b) Determine the resistance reflected into the primary. Answer a) R(l): 35V, 2.91A, X(cl): 15V, 1.5 A The answer to part (b) is apparently 34.5 Ohms. How did they arrive at these answers? I am not sure...

I am looking to step up the voltage of a 3 phase PM generator which has variable AC output of 200 - 400 Vl-l, and 15 - 30Hz. I am looking for a step up ratio between 1:1.5 and 1:2, and need this transformer to be a commercial device. What i have been finding is that most commercial...

Over the years I've learned a lot about TXs etc. But I'm a bit rusty. Any thoughts on general reminders about core saturation. I know there are huge issues, but the specifics I can't remember that well. I vaguely remember hearing something like when there is a DC component on a transformer the...

In transformer, lamination is an effective method to minimize eddy current and thus energy loss. I just wonder how can we show that the energy loss due to eddy current in those laminates is added up to be less than that without lamination (suppose the total cross sectional areas are the same)?

Homework Statement A load of 1000 kVA at 0.866 p.f. lagging is supplied by two 3 phase transformers of 800 kVA capacity operating in parallel. Ratio of transformation is same : 6600/400 V, delta/ star. If the equivalent impedances referred to secondary are (0.005 + j.015) ohm and (0.012 + j...

Homework Statement I have a step down transformer (6 : 1) Copper Loss of 110W at full Load Primary Coil: I = 3.33A R = 0.35 Ohms Power Loss = 4W Secondary Coil: I = 20A R = 0.265 Power Loss = 106W Power Drawn Over the Primary = 75W 9kVA Transformer Homework Equations The Equations i have...

Homework Statement A transformer has a turns ratio of 5 : 1. It is connected to a 230 V supply and an output (secondary) current of 2.7 A is measured. If the transformer is 90% efficient, calculate: Secondary voltage Input (primary) current [/B]Homework Equations...

Just curious about why grounding transformers are used with a delta secondary . What would happen if I connect a phase to ground load to the secondary of a star delta transformer without adding a grounding transformer?

Hello everyone, I'm not sure if the title makes sense, but I'll try to explain it a bit better here. So, if we have a transformer with an open iron core (U shaped iron core, with coils wrapped around each side, same number of coils, same thickness), why is the electromagnetically induced emf in...

Hi guys, I am rather new here and would like to pose a question about transformers. As physics assignment I am supposed to make a model of an AC transformer, for which I grabbed an AC/AC step down adapter (something like these here...

So I am trying to understand how a ULTC operates in the Reactive Power Control mode (it adjusts taps to control the reactive power in a line). What equation is governing it's operation, and what variables does it adjust in order to increase/decrease reactive flow? Is it just the simple reactive...

I have a few questions regarding general transformer workings, and a couple of questions regarding toroidal transformers as well. For ease of reading I've put them in bullet points: 1. The magnetic flux induced by the primary winding creates the voltage (and hence current) across the secondary...

hello! isolation transformers are supposedly protecting from electric shock without them, the voltage source is connected to a circuit and the circuit is connected to Earth via an earthing wire. if you touch the live circuit, a closed circuit will be formed that will give you electric shock...

Homework Statement A short circuit test is performed on a small single phase transformer. The results are: Primary Voltage 5V, 60Hz Primary Current 2A Secondary Current 10A Primary Power 8W a) Making suitable approximations deduce the primary/secondary turns ratio (single number)? b) Making...

Homework Statement In the circuit shown the 120V, 60Hz source supplies the ideal load shown through an ideal 2:1 transformer. What steady state current would you expect to read on the rms ammeter shown (please find the picture attached)? Homework Equations Zeq = (1/Z1+ 1/Z2)^-1 Z1 =...

i am having some trouble with understanding the magnetic fields inside transformers and how they relate to back emf. In particular, I am considering the two cases of current passing through the primary coil but not the secondary coil, and then with the secondary coil as part of a complete...

Do transformers change the resistance of the wires inside then when turned on? The reason I ask is because I know that transformers can be used to change the ratios between voltage a current while keeping the power sent in and power sent out roughly equal, but since V=IR this must mean that the...

I have read that transformers operate on high power factor but I cannot get what is the reason behind it..?? I mean..what if we are having a low power factor..how is that going to affect the working of transformer??

Hiya Does anyone know if there's any safety or performance issues with going about the input voltage of a transformer? The spec on maplin says on just about every step down transformer that the input is (x)v-230v. As I live in the uk, mains voltages are 240v a.c. Not sure about what to do

Hopefully this has not already been asked. It would be hard to do a forum search with the right words to find it if it has been already. I am wondering if it is ever possible or common place to generate power in a Wye generation scheme and then connect it directly to a transformer with a...

So I was just reading on generators. The basics that I've understood is that it works by inducing a current through motion of a coil on a magnetic field. So what I didn't understand was that it produces an alternate current through full 360` rotation. In a half cycle, it induces a current in one...

I’m looking to purchase a toroidal AUSTRALIA-to-US stepdown voltage transformer, and have narrowed my choice down to two models, one permitting a maximum rate of energy consumption of 100 Watts, and the other permitting a maximum rate of energy consumption of 250 Watts. Both of these maximum...

I need to find something that I can wrap around the coil of a bottle radio (image below) to keep the magnet wire from unwinding. Lacquer is messy and time-consuming. I'm hoping there is a translucent tape that I can use? Someone suggested using Kapton tape, but it's very expensive and a bit...

I am working on my final year design project, and I will be using magnetic power harvesting from a power line to supply a microcontroller. I am thinking of using wires around an iron core, or just purchasing a CT for harvesting energy. If it is the CT, I am a bit confused on its ratings. If the...

please suggest me simple and pecise notes or book for the above that can provide full concept in a very short span of time perhaps this is not the homework.

I know that in a step down transformer the voltage is reduced and therefore current has to increase because P=IV. But potential difference is what drives the current so when the voltage decreases it seems strange for the current not to decrease too. Another why of putting it is if both coils...

I am learning about transformers and from everything I've read I can see how its possible to create a 180 degree phase shift by winding the primary and the secondary in opposite directions. What I wanted to know was if it's possible to make a 90 degree phase shift with a transformer.

I was shown how to use two transformers to step up voltage and I am curious as to how it works. The low side of the transformers were connected to 120v and the high side was connected to a load at 240v. What amazed me was that the low sides connected in series could be connected to the 120v...

We all know Ohm's law and power conservation, but in a basic transformer, they seem to be contradictory. For example, say we have a 50v source running through a 10Ω wire, then the amperage to the transformer should be 5 A and would come out to 250 watts. Then say the transformer steps the...

Homework Statement This was in my test paper today: A transformer is cut into half so that one half contains the primary coil and the other half contains the secondary coil. They are moved 30cm apart. Explain why the transformer would not work The Attempt at a Solution My answer: The magnetic...