Transformers, Electrical Engineering

AC Operation of an iron core

1428_Transformers.png

 

 

 

563_Transformers 1.png

 

Hence, if a wattmeter were used to measure the power delivered over a full period of the waveform (which will also be the average power delivered over a long period of time), the answer should be zero.  In practice, there will be a finite energy loss recorded, which is found to be much larger when the coil is wound on a conductive former than when it is air cored.

The energy loss is attributed to:
 
 
1) 'Copper losses', i.e. loss due to current flowing through the resistance of the windings, (P=iR).This power loss occurs whether the
core is air cored or not.

2) 'iron losses'. These arise due to two causes:
 
a)  the hysteresis loss due to the energy dissipated in continually reversing the magnetisation of the core. The energy taken per cycle is the area of the hysteresis B/H curve.

b) Eddy current losses due to  induced currents circulating within the conductive core of the coil. These are induced by the changing current in the coil and circulate in such a way as to try to oppose the change in the coil current. They are minimised by laminating the core to increase the path resistance for the circulating current and hence reduce its value. Since Power = i.R, reducing the current reduces the power even though the resistance is increased.

A transformer is produced by winding a second coil onto the former.

1393_transformer is produced by winding a second coil.png

 

Note the polarity of the currents. The current in the primary coil creates a flux in the core with a direction according to Maxwell's RH corkscrew rule. The current induced into the secondary coil is in such a direction as to try to oppose the original flux change in the core.

 

 

Posted Date: 8/23/2012 3:16:26 AM | Location : United States







Related Discussions:- Transformers, Assignment Help, Ask Question on Transformers, Get Answer, Expert's Help, Transformers Discussions

Write discussion on Transformers
Your posts are moderated
Related Questions
1 diagram basic layout of a simple transformer

Q. A gyrator is sometimes used in integrated circuits to simulate inductances. Consider the circuit of Figure consisting of a gyrator. (a) Show that the impedance as seen to the

What are the basic modes of operation of 8255? There are two basic modes of operation of 8255, viz. 1. I/O mode. 3. BSR mode. In I/O mode, the 8255 ports work as progr

For the amplifier circuit shown below estimate the mid band voltage gain if the EARLY voltage (V A ) of the current mirror transistors is 80 volts.  Assume the d.c biasing is optim

a 49pf cap,a 50 uH inductor, and a 100 ohms resister are in parallel: what is the resonance freq? And what is the complex impedance vector at 100MHZ?

Figure shows the cross-section of an electrostatic problem with translational symmetry: a rectangular coaxial cable. The inner conductor is held at 10 volts and the outer conductor

Objective: To Understand the Usage of the Output ports of PIC18F452 and make changes in the previous code accordingly. Procedure: 1. Open the p1.asm program from t

I need someone help me to do electronics formal lab report, I tried many time to submit it but I couldn''t? plz help me

Call Instructions Call instruction are used to call a  subroutine program in assembly language  procedure and functions are called  subroutines. There are two types  of calls i

What is AGP? AGP: The latest addition for many computer systems is the inclusion of the accelerated graphics port. This AGP operates at the bus clock frequency of the microproc