Transformer Definition and 787 Threads

Why will current decrease when voltage increase in a transformer ? I 've just learned it and I get confused. Assume there are 2 solenoids, the no. of turns of coils in the left sides one(with AC current) is less than that in right sides.By conservation of energy, V(left) x I(left) = V(right) x...

Consider a biresonant transformer with a small coupling coefficient k << 1. Let the voltage applied to the primary LC circuit be U1(t)=U*sin(2*Pi*f*t), then also the current I1 will be sinusoidal. The voltage induced in the secondary winding and the current in the secondary LC circuit will be a...

So with my final test tomorrow I thought to sneak in another question... Homework Statement The following circuit applies switch at the load RL via Zero Point Switching. The ratio of the coil windings at the transformer is N1:N2 = 4:1. The introductory voltage is a sinusoidal type and its RMS...

I need a transformer with the following characteristics that can operate at a frequency of 1MHz. Step-up ratio= 1:80 Primary L=1.55uH Secondary L=10.65mH Mutual Inductance= 62.5uH Any suggestions on what US companies might carry this kind of product?

Got cascade voltage transformer made from two completely identical units. On secondary winding, load takes I2=1A Number of compensation and secondary windings is equal. I need to find current trough compensation winding Ic . θ1 = θ2 --> θ1 = I1N1 + IcNc - I2N2 --> θ2 = I1N1 - IcNc --> I2N2...

I was just curious if anyone could point me in a direction on how to read transformers that are not industrial transformers? I ask this because I'm new to the field of electronics and I found an old transformer from my grandfather and the only information written on it is PT-54-A next line...

hello there ; I have several questions about the 3-phase transformer connections and I will be really grateful if anyone could help ... I've learned that there are several types of 3-phase transformer connections which are in general ; the (Wye-wye) , ( Wye-Delta ) , (Delta-Delta ) , (...

I just built a transformer to the specs of the original. The transformer has a turns ratio of 1:16. Input to primary is 12V. The problem I am having is a very low voltage at the secondary side. The no load voltage was the highest (40V) that I have got out of it so far. The primary coil...

For a no load ideal transformer V1 is anti phase with E1? or in phase like this?

I am looking to power a heater. According to the product specifications it will require 11.1V/26.4A to heat to 800C and 16.9V/33.1A to heat to 1000C. The manufacturer sells an expensive temperature controller which we would like to avoid using. It has been suggested to me that I use a variable...

Hi We have a project where we have to install an HVAC system but only a 3-phase supply is available. While that is fine for the motors inside the unit, it means that there is no neutral available for the control circuitry. I am aware that a "zig-zag" isolating transformer can provide a...

Hi, the explanation I have been given for how a transformer works is this: The current flows through the primary coil, hence generating a magnetic field around the coil. Imagine that the coil is wrapped in the anticlockwise direction around the soft iron core (and hence current flows...

hello friends...i am facing difficulties in understanding the difference between live type and deadtpe current transformer...and also the advantage of live type over dead type?

A secondary textbook said that if there is no flux leakage, Vp/Vs=Np/Ns, no matter what is the efficiency of the transformer. May I know will the ohmic loss and eddy current contribute to the loss and modify the voltage ratio? thanks!

How does a transformer react to a changing frequency Obviously the inductive reactance of the primary changes, which causes a decrease in the current for an increase in reactance, then so too shouldn't the output voltage be less? This seems to contradict Vs/Vp = Ns/Np What I am saying is...

Using characteristic diagrams, describe how a Transformer produces a complex waveform from a sinusoidal input. can someone in the community please help me with this , ref. to a web informative page etc would be fantastic as any i find are way to complex for the level that i am at ( hnc ) any...

I'm reviewing transformers and I have some confusion over the current s is for secondary and p is for primary I know that Vs = Vp(Ns/Np) and Ip = Is(Ns/Np) So when you have a load across the secondary terminal you get your current through Vs/Rload. But does this mean for current in...

I have read that when the secondary of a transformer has current flow, it will reduce the magnetic flux in the core. This then reduces the back-emf on the primary, causing a increase in current to reestablish the magnetic flux to what it once was. What I want to know is when the secondary...

Why is the Voltage induced on the secondary of a transformer in phase with the primary? As far as I know, lens law states that any induced voltage on a coil is 180 degrees out of phase with the coil that generated magnetic field. Otherwise you could have infinite energy systems, lol. Is the...

Homework Statement For a transformer, the ratio number of turns on the transformer secondary : number of turns on the transformer primary = 21 : 1200. If the input voltage is 120V AC, what is the output voltage? Homework Equations \frac {N_{P}}{N_{S}}=\frac {V_{P}}{V_{S}}...

I'm having trouble understanding how a pole mounted transformer is wired. I am astounded at how little information is online about one of the most common devices on the grid. The typical single phase transformer has a single wire connection from one high voltage power line. To have a...

Homework Statement A step-down transformer going from 240 V to 12 V is 95% efficient. The input current is 20 A. a) Determine the primary turns: secondary turns ratio necessary in order to maintain a 12V output. b) Determine the output current. I have solved it as if I needed an secondary...

I have attached the problem. This is a practice exam and the answer Imax = (N2/N1)^2 * (Emax/R) but I have no idea why. I have been trying to manipulate the transformer equation I2/I1 = N1/N2 = V1/V2 but to no avail. Thanks

Dear Experts I have a 1.5 cm ring magnet, you know, the black color type of common low magnetic power magnet. I wrapped 5 turns of copper wire around it on one side and then wrapped 10 rounds of another copper wire around it . I connected 5v battery to the 2 ends of the primary coil which...

Hi, I have an old high voltage furnace ignition transformer with no specification plate on it, When plugged to 240v it gives about 10mm arc length; with no proper equipment to measure such high voltage I was wondering if I can plug it 50v and measure the output to calculate the ratio. I'm also...

Homework Statement An ideal (lossless) transformer has 4 times as many turns on the primary winding as it has on the secondary winding. The secordary winding is loaded with a 10k ohm resistor and a sinusoidal voltage source having negligible resistance and a peak voltage of 10V is connected to...

When you have no loads connected to the secondary of a transformer, what is the current in the primary? When you start connecting loads to the secondary, what phenomenon is making the current increase in the primary?

Ok I've read a lot of articles and seen a lot of different ways of calculating the short circuit current at the transformer terminals. So I'm going to apply my own intuition and see if I can arrive at the correct value if someone could please confirm my answer. 6.6kV/400V 3 Phase 10MVA...

what is the difference between a current and voltage tranformer constructionally and functionally??

Homework Statement A single phase transformer has the following rating: 120 kVA, 2000 V/100 V, 60 Hz with 1000 primary turns. Determine: a) the secondary turns b) the rated primary and secondary currents c) the maximum flux d) given a maximum flux density of 0.25 T, the cross...

Hi, Something is puzzling me with the HVDC work I'm currently working with. I'm working for contracting company here in NZ contracted to complete the new HVDC converter station. We have 3 x single phase converter transformers on site converting the AC voltage. I was wondering why when...

I am asked to compare analytical values of the loaded transformer with measeured values of the transformer. I have got no clue how to do that. The transformer is singl ephase 230/115V with rated secondary current 0.43 A. According to open circuit test the Rcore = 15.9kOhm, Xcore = 10.5kOhm...

I was recently going through electric machinery fundamentels by Stephen Chapman and noticed the graph of the core loss current. I need help in understanding the nature of the current graph plotted against time, like how its value stays constant for some fixed time then varies linearly.

Homework Statement The primary coil in a transformer has a power of 100W. The flux through a single loop in the primary is changing at a rate of 25 Wb/s. The primary has 100 loops and the secondary has 500 loops. Assuming a perfect transformer (no losses), determine the current and...

Homework Statement Even for an ideal transformer, we can't get "something for nothing". If this transformer steps up the voltage, what must be decreased? a) power b) current c) resistance The Attempt at a Solution Ep/Np=Es/Ns I believe it's power or current, but these two are related. So...

Homework Statement http://www.xtremepapers.com/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s02_qp_4.pdf <------ CLICK ON THE LINK The Attempt at a Solution Is the above diagram the correct answer ? Please note that the diagram in the question paper is for COIL...

Is it possible to build/purchase a 10kV (nominal) flyback transformer which runs on about 2 Watt or less?

Modified microwave transformer- need advice for rectifiers and wire ratings. Hello everyone. I've been doing a lot of research as to how to go about purifying copper. There are two approaches I'm considering. Electrolysis and Smelting. The electrolysis method requires I have a DC output of low...

Hey guys, Just looking for some reassurance as to whether I have visually depicted the wattmeter and current transformer correctly in the image I have provided. Needed to step down current to satisfy current ratings of wattmeter. One thing I cannot seem to see is how it detects the voltage...

When I calculate efficiency of a transformer, I use output power/imput power x100%. Then what are these power values? Is the power the power in a load or the total power coming out of the transformer (meaning it includes the joule heating)? Then also what about the input power, which values do I...

Does anyone think that it's possible to have a perpetual motion machine electricity generation of a combo of a light bulb shining light on photovoltaic cells that are connected to power increase transformer coils to power that light bulb? I suppose there would have to be some kind of way to...

[b]1. attached is the question i am trying to solve. I do not know how to do per unit questions. [b]2. Part a) of the question ask to convert into per unit and then per phase equivalent circuit. I do not understand how to do it. Please guide. Also, how to calculate the bus1...

Homework Statement See attachedHomework Equations V2/V1=I1/I2=n n=2The Attempt at a Solution \begin{array}{l} {\rm{Mesh 1: }} & 4{I_1} + {V_1} = 60 \\ {\rm{Mesh 2:}} & 10{I_2} - {V_2} - 2{I_3} = 0 \\ {\rm{Mesh 3:}} & - 2{I_2} + 10{I_3} + {V_2} - {V_1} = 0 \\ {I_1} = -...

Homework Statement Hello everybody, am confronted with this question: A transformer with 5500 turns in its primary is used between a 240V a.c supply and a 120V kettle. Calculate the number of turns in the secondary. Homework Equations The equation Es/Ep = Ns/Np can be applied in...

I would like to do the mathmatical modelling then apply it in matlab. This is my trailier. Vp-ip*Rp-Lp*(dip/dt)-Rc*ic = 0 ----- 1 Vp-Lm*(dim/dt) = 0 ------2 i need the modelling of the secondary voltage to the primary and the flux Vs= ? flux= ? I did apply it in MATLAB but didn't work.

I decided to make a couple solenoids. Not too many loops on them though as I need higher gauge wire. After getting that I put one in the other and in that a core of metal that had some iron in it. I tried inducing a bit of current in the outer winding by driving DC current through the inner coil...

When transferring electricity from a generator to a factory or anything we would use a transformer to step up the voltage right? As P=VI and P is constant in the primary and secondary transformers (ideal case), with an increased V as compared to the primary transformer it will in turn result in...

Homework Statement 27.An alternating current power supply rated at 120 V is connected to the primary coil of a transformer. The coil has 200 turns. The secondary coil has 600 turns, and is tapped 200 turns from the top end, as shown. What is the reading on voltmeter V1? (diagram attached)...

i may need your help for following question. 15kva, 2300/230v, 50Hz transformer has voltage drop of 2% and 4% of load voltage, due to winding resistance and leakage reactance respectively, at full load. 230v is maintained at the secondary terminal. The full load copper loss is equal to the...

I need a 10-15 : 1 step-down transformer for an electrolysis project. It needs to be capable of about 150A. I have an old ex-military transformer/rectifier, but it outputs 200A at upto 230V DC. It has a humungous transformer in it , and some banks of BIG diodes, so if I get a variac from ebay...