Transformers
This presentation is the property of its rightful owner.
Sponsored Links
1 / 57

Transformers PowerPoint PPT Presentation


  • 71 Views
  • Uploaded on
  • Presentation posted in: General

Transformers. Transformers. The "simple transformer law" relates output voltage to input voltage and turns ratio. Investigate the importance of frequency and other parameters in determining the non-ideal behaviour of transformers. The "simple transformer law".

Download Presentation

Transformers

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Transformers


Transformers

  • The "simple transformer law" relates output voltage to input voltage and turns ratio. Investigate the importance of frequency and other parameters in determining the non-ideal behaviour of transformers.


The "simple transformer law"


Using the Kirchhoff's andFaraday’s laws


Neglects

No magnetic hysteresis

We also need to separate running with load and free running, as it’s particular case.


Dependence of coefficient against frequency (with load)


Dependence of coefficient against frequency (free running)


Dependence of coefficient against voltage


Dependence ofcoefficient against resistance


Part 1

  • Measuring parameters of our transformer


1st experiment: VAC

A

Ohm’s law:

V

We used small DC voltages to measure the resistance of the winding


Plot VAC, 1st winding


Plot VAC, 2nd winding


Theory

We will seek the solution of this equations in form:


Vector diagram

~


Inductance. Currentfading

V


Measures by currentfading


Linearization


Calculation from graph of inductance


Theory and practice, dependence on frequency(with load)

theory

experiment


Dependence M against frequency

M(mutual inductance factor) depends on frequency because of depending µ on it


Dependence on frequency(with load) after addition M dependence


Diffusion flux

Diffusion flux

Inside flux


Demonstration. Flux.


Without core


Rotation


Dependence of coefficient against angle


Linearization


Part 2

  • Describing all looses in the transformer


Losses

We measured steel losses using the chain (right).

A

V

V

~


Steel looses. Foucault currents

r

h


Dependence offull losses in the 1st winding against voltage


Dependence oftemperature losses in the 1st winding against voltage


Dependence ofsteel losses against voltage


Dependence ofdiffusionfluxagainst voltage


Rebuilding a chain

We can rebuild our chain using diffusion inductance


Including diffusion flux


Demonstration. Ferromagnetic


Part 3

  • Measuring and modeling hysteresis


Hysteresis


Changing U0


Modeling hysteresis loop

If we know all the coefficients, we can have as a result of our model real hysteresis loop


Modeling changing signal


Changing w


Changing n

  • We are changing numbers of coil turns

A

V

V

~


Dependence ofcoefficient against number of turns


Theory


Resonance mode

We can imagine a real winding as system of coils, resistances and capacitors.


Conclusions

  • Transformer coefficient depends on

    • frequency because of the resistances of windings and the dependence of induction on frequency

    • the load because of the resistance of the 2nd winding

    • input voltage because of hysteresis mode

    • turns number of the windings because of dependence M on it


Thanks for your attention


Доп слайды


Dependence ofsteel losses in the 2nd winding of voltage


Dependence of coefficient against frequency (with load)


Changing amplitude of U0


Unideal transformer

Resistance of the winding

Losses of the flux

Losses in the core


  • Login