Transformers Definition and 267 Threads

I have an exam on monday and looking through the past papers I came across a question I couldn't find a suitable answer to: List the economical advantages of using a transformer in a train rather than run the overhead lines at 400V? any help would be very much appreciated... Phil N

In regards to the small, black box transformer-rectifiers one sees all the time on things like printers, speakers, battery chargers etc... for computers and other appliances, how tight are they on specifications for output? For example, if I have a device that is rated 12V DC and 4 amps, how...

Question: A short circuit test is performed on the low voltage side of a 40-kVA 4800/240V 60HZ transformer and the following data are obtained: W = 240W, V= 66V, and I = rated current. Determine the percent voltage regulation with a 0.88 lagging PowerFactor load connected. On the Short cct...

Hmm..i got a qns here..why is it that some transformers emit a hummin sound when connected to a AC of 50 hz supply??..also, how do we know what the freq of the hum?seems like there is no link to me..:confused:

I've heard that lightning or extreme heat can make transformers blow. Well, I've had it happen near me twice recently, and neither time was due to lightning (AFAIK) or heat (it's winter). One time coincided with a car hitting a pole (actually, the supporting wires that are keeping it from...

http://robot-fan.net/spot/spot067.html What can't the japanese do?

Does anyone know where I can find information on Balancing Transformers. A co-worker asked me about them, and I have not had much luck finding information on them. I do know that they are used when you have duel power sources, like two generators. The transformer syncs the frequencys and...

Hey everyone, I had a question on a question about transformers: The primary coil of a transformer contains 100 turns; the secondary has 200 turns. The primary coil is connected to a size AA battery that supplies a constant voltage of 1.5 volts. What voltage would be measured across the...

"Iron core energy change" and "transformers vs. ohms law" Ooh yes, I do have two question. So enjoy the meal all physics lovers! :smile: 1. If the field is increased putting an iron core inside the circuit, then what about energy conservation? (I don't know much about H-fields.) 2...

Suppose there are two transformers between your house and the high-voltage transmission line that distributes the power. In addition, assume that your house is the only one using electric power. At a substation the primary of a step-down transformer (turns ratio=1:29) receives the voltage from...

1) A transformer is designed to change 120 V into 10,000 V, and there are 5,000 turns in the primary. How many turns are in the secondary, assuming 100 perfect efficiency? 2) A transformer has 420 turns in the primary and 120 in the secondary. What kind of transformer is this and, assuming...

Hello, Anyone who is kind and knowledgeful please provide me some links and/or detailed explanations on how to produce Expandable Arms... The reason is that I am interested in how to create Arms which can be expanded using Motors, and/or other types of technicles. Arms with such capability...

Let's say that there is a transformer with 10 loops on one side (side A) and 100 loops on the other (side B). If ther is a rms 10V potential difference produce by a generator on side A, then there would be a rms 100V potential difference on side B. It would seem like the resistance through the...

A transmission line that has a resistance per unit length of 4.5*10^-4 ohms/m is to be used to transmit 5 MW over 400 miles (6.44*10^5 m). The output voltage of the generator is 4.5 kV. a) What is the line loss if a transformer is used to step up the voltage to 500 kV? b) What fraction of the...

I was just wondering how transformers actually operates. And I hear they need to use alternating current and I was just wondering why they need to do so.

I need help find a good page which talks about the physics of a tranformer. I know all about the b fields and the flux and the ratio of the windings but what I really need is the practical formulea and methods for example calculating the voltage drop on the primary if the secondary has...

Im a high school student/newbie at this stuff. In physics class we just started going over the electric grid. My teach first talked about how transformers are used to get high voltages for long distance travel. If I understood him, he said transformers boost the voltage while droping the...