Transformers Definition and 254 Threads

Homework Statement It is required to transfer an electric power of 80. Kilowatts from a powerstation to a factory which is at 2 km from it.If the potential difference (here it means the voltage of the source) at the station is 400 volts and the resistance of 1km of the 2 conducting wires is...

Hello! I'm still not clear on a few things: For example: Let's say a manufacturer creates a device which runs at 120W (let's say a lightbulb). Does this mean that i can use which combination of voltage and current such that V*I=120W i want? Another example: Let's say that the maximum...

transformers -- Don't understand VpIp = VsIs Homework Statement If the equation below of any transformer is true, therefore it does not matter if i connect a lightbulb or anything else either to the primary or the secundary, it should be working the same, right? I have a 220v-3v step down...

Homework Statement A 50 KVA,6360 V/230 V transformer is tested on open and short-circuit to obtain its efficiency,the results being as follows: O.C.: Primary Voltage-6360 V, Primary Current-1 A, Power Input - 2 kW S.C: Voltage across primary winding-180 V Current in secondary...

Hi, I'm trying to figure out what phase differences take place with an ideal transformer. This is what I have figured out so far: If you apply an AC current to the primary coil then you will get an alternating flux in the primary and secondary coils simultaneously therefore the fluxes are in...

If you apply 100 volts to a 10:1 transformer you will end up with 10 volts out. If you put a 10 ohm resistor on the secondary you will have one ampere passing through the resistor. That's it !' Why do I have to apply energy conversion equation to find the intensity it seems meaningless, why...

Homework Statement Hey there! I have simple problem: To start a spark in a car ignition system, voltages of 5-17kV are required. A transformer with winding ratio 1:100 is used with a 12V battery, so we get a 1200V voltage. How are higher voltages achieved in such systems? Thanks

the law of the transformer states that in primary coil , the EMF = -n multiplied by the rate of change of flux with respect to time but that law applies to induced EMFs , and since the voltage in the primary coil is not actually induced but rather produced by an external source of A.C , then...

Homework Statement We have a transformer with the primary coil carries 120 V and the secondary coil having 6 V. If you change the second coil to have 8V, what is the voltage in the primary coil? Homework Equations My textbook does not have any equations that involve just the voltage of...

Homework Statement We have a transformer, the primary coil has 120V and secondary coil has 6V, if you put 8V in secondary coil, what will be the voltage in the primary coil. Homework Equations v1/v2 = n1/n2 where v is voltage and n is turns The Attempt at a Solution So i was...

Hi, I'm trying to comprehend the idea of why the induced current of a transformer decreases as voltage increases. Is this in terms of an increased applied voltage? I know that if you have a high applied voltage through the primary coil, if it has a high number of loops, this will cause for a...

Can anyone explain why saturation current and flux leakage are not related? saturation current = current where all the magnetic domains are aligned right? flux leakage = flux from the primary that doesn't reach the 2ndary can someone also explain why, flux leakage causes a increase in...

I had a new slot car race track with step down transformer given to me by my Grand Parents for a birthday present. One thing I did notice, is the car with the lowest internal resistance motor used to go faster, well that's what my Dad told me at the time. I found this to be very true on a...

Transformers -- Why output current decreases for step-up xfmr? So I've been wondering if anyone in PF could explain to me the reasons currents can either increase or decrease in a transformer depending on the wiring. I understand electromagnetic fields/forces, magnetic flux, and I even could...

Hello Guys ! While Studing coupling transformers i found this problem i tried to solve it but i don't know if my solving is right or no ! so tell me :) The problem : My solve is : V(out)=nV(in) V(out)= 2 * 312 = 624 v PIV = V(out) = 624 v and if the diode is turned...

Hello, This is my first post, so I hope this is in the right section and format. I've looked all over the web, but I can't find anything that addresses my question clearly. I know that for an ideal transformer to not lose any power, the turn ratio has to be the square root of the...

Hello, I am currently working with mono phase transformers. I would like to know if there is an equation to calculate the voltage when the core saturates so I can compare with my practical results with. Thank you very much João

Hello, Is it true that when using transformers and three-phase drives/VFDs for induction motors, the transformer's power needs to be much higher (e.g. +40%) than the drive's in order to avoid increased harmonics (or even other problems)? If you know any official standard, paper or...

I know of multisim, but that is mostly fo rlow voltage applications. I need a schematics program like multisim, that has models of big transformer stations, current transformers, fuses, circuit breakers etc. Anyone of you who knows of a tool like this?

Dumb question - if the phases are tied together in a three phase delta transformer why don't the phases short out against each other in the same way the transmission lines would fault phase to phase if the touched each other in the overhead? I think I understand the wye winding situation in...

Every time I walk by the electrical transformer at the end of the lane, I hear a low humming noise(≈50Hz) that is continuous. I have observed this in all types of fans. I grab the hub so that it is not able to rotate and switch it on. Then I hear this hum. When the mixer/grinder chokes, it...

I am starting to learn about transformers, and know the basics: they use electromagnetic induction to induce a current in a secondary coil, and the voltage and amperage of that second coil are dependant on the voltage and amperage of the first coil, and the ratio of turns in each coil. So...

transformers -- winding resistance and leakage reactance Does anyone know what is meant by: 'determine the combined winding resistance and leakage reactance referred to the primary side'?

Homework Statement I have got this scheme: Alternating voltage V = 120 V, Total resistance of wires Rw = 0.6 Ω Current is 100 A, ratio 1:5 and 5:1 (as we can see it in the scheme) Have to calculate dissipated power in the load (Pl), dissipated power in the wires (Pw), total dissipated power...

Looking for a recommendation of a book I can take out from the library at my University. I am looking for a book that has questions & answers (even or odd) to circuits involving transformers. I currently have a textbook with problems, but it has no answers. I find it rather pointless working...

The hysteresis iron loss is give by Ph = Kh*f*Bmax^1.6 And eddy current loss is given as Pe = Ke*f^2*Bmax^2 At first it appears both loss increase with frequency (f) but recognizing that for fixed magnitude of applied voltage, Bmax = k/f , we can see that Pe remains constant and Ph decreases...

transformers -- question about number of phases used [FONT="Arial Black"][SIZE="4"] why often single phase and three phase transformers are widely used rather than other phases like four,five phases

Can anyone please clarify if the current in the primary coil of the transformer follows V(s)I(s)=V(p)I(p) when i am trying to figure out the peak, surge and average current through the primary coil of a transformer in a full wave rectifier. Also, if it does, do I just use the peak voltage or...

How is that two hot phases can be put into a transformers and it not blow up? i have asked this question many different times to different engineers at work and I'm tired of hearing "just because". please explain in detail

Hi there, I've got a fairly simple question theoretical question about transformers and I suspect it stems from a misconception I have about them. I understand that step down transformers can be used in situations where a high current is desired but that they also reduce the voltage in the...

Homework Statement the smal transformers that power many consumer products produce a 12.0Vrms, 60hz EMF. design a circuit using resistor and capacitors that uses the transformer described above as an input and produces 6.0 Vrms output that leads the input voltage by 45 ° Homework...

What types of losses can occur in transformers?

Hi, Can somebody answer this question? The induced magnetic field of the secondary coil opposes the magnetic field of the primary. Therefore there is a lower magnetic field on the primary - lower impedance and a lower voltage drop. This results in an increased primary current which will...

How we speak about the coil of primary in phase of a versus secondary coil this is accepted (as there is on same core) But question about we say this transformer (ex) is vector group Dy11 that means phase difference between primary and secondary voltage is 330 angle ! It's conflicted...

Hi folks, I'm a Mech Eng who is trying his hand at some Electrical design so please forgive my ignorance. My set-up is as follows: I have a 3 phase source powering a 3 phase induction motor. If I then went half way along my power cable and put a separate current transformer on each of the...

There is probably a very simple and obvious answer to this question, but right now it's just not clicking for me. So, perhaps someone else can help me out. Context: The typical undergrad intro to the Aharonov–Bohm effect is that it is an intrinsically non-classical phenomenon because an...

My first question is with the relationship between current and voltage. I understand how they are related mathematically but not conceptually. Why would increasing voltage decrease current if the resistance stays the same? Why couldn't the current increase if there is more "push." This leads...

Hello, Suppose 2 single phase transformers have the following: T1 T2 Rated Current 200A 600A Resistance(pu) 0.02 0.025 Reactance(pu) 0.05 0.06 No-Load emf 245V 240V What is the terminal Voltage when they are connected in parallel and supplied a load impedance of...

When it comes to power plant transformers, What is the typical inductance and impedance on the primary winding?

hi, in megger test of transformers which terminals we have to Earth and why? How this test is used to check insulation?

Hi, What does rated output in a transformer signify? Is power same(or almost same) on both sides? In short circuit test, we apply reduced voltage to HV winding so as to circulate rated current in HV. This will cause rated current to flow in LV. But as per definiton of rated current...

Homework Statement Ok so i was doing my revision for my exams and i was reading on transformers and they said that stepped-up Voltages and stepped-down currents minimizes for tranformers I^2R power losses in the transmission cable. I know that current is decreased, but a higher voltage, by...

What type of software? Hello everyone, I'm looking for a simple software program that I may be able to configure coils, inductors, transformers, core selection etc. Basic ic availability, selection of switches, LEDs, types/strenghths/shapes of permanent magnets. I'm aware that there is a lot...

How are described in the Industry those transformers able to operate with a variable frequency? These transformers will be used downstream of a Frequency Drive. Anyone knows? Any specific characteristics? Thanks

Hello, Suppose a simple transformer, not connected to a circuit (just to the home AC). If we get a multimeter and measure its resistance we will get a number. So if we plug it into the home AC, it will consume energy (constant power). Now suppose we have a desktop computer power supply...

I see a lot of these transformers that claim to do both step-up and step-down in the same unit. At least one had a photo of the back side and there was a switch labeled to set it according to the input voltage. What I am curious about is how these are wired. Are they isolation transformers or...

Homework Statement 65 kW is to arrive at a town over two 0.100 ohm lines. Estimate how much power is saved if the voltage is stepped up from 120 V to 1200 V and then down again, rather than simply transmitting at 120V. 2. The attempt at a solution First I want to find the power lost in...

This question about the variation of the aforementioned quantities in a transformer. Now according to me and my knowledge of electricity this is how I feel it should play out : If the input current were a sine curve that varies with time then : Input voltage = cosine curve i.e. it is...

Ok, I have a primary and secondary coil. I set up a transformer between them. Each has 400 turns of coil(N). The primary coil produces a potential difference of 2.988 V. The secondary coil has a potential difference of 0.0551 V. For the efficiency, I used the equation (Np*Vs)/(Ns*Vp) * 100%...

http://imgur.com/VsDrQ,dJ2iv#1 So according to the picture, I found the transformer voltage equation and current equation to be the following: Precondition: i1 is current in left loop i2 is current in 2nd loop Transformer Voltage Eq: V1/N1 = 4i2/N2 Current Eq: Ni(i1) =...