There is an old joke the institute.On the question of the teacher "how the single-phase transformer," the student answered buzzing: "Oo-oo-oo!".Sound this is indeed the case, it is due to the fact that when you move the induction magnetic field arises striction effect, causing the magnetic plate to vibrate.
single-phase transformer is designed to create an alternating voltage to the desired value of the load, it does not require three-phase power supply.
Each transformer consists of two basic components: the core and the coils, they can be at least two.The principle is simple.The passage of electric current through a conductor in the primary winding, the secondary induced electromotive force (EMF).The core consists of ferromagnetic plates, that is, material, enhances the magnetic field (electrical steel special grades).
magnitude of the EMF determined by the formula:
E = 4.44 x F x X f ω
where:
F - the amplitude of the magnetic flux;
f - frequency of the current;
ω - the number of turns in the winding.
Allowable load power, which "pull" single-phase transformer is given by the wire section, which coils are wound, and a good magnetic, in particular ferromagnetic permeability μ.The size of the core and number of turns are the subject of calculation, which is often the subject of the course work in technical colleges.
In any case, more powerful single-phase voltage transformer, the size of their impressive.Their body often has a label listing the main parameters (permissible current input and output voltages).However, this does not always happen.
In practice, many repairers are often faced with the need to replace the burned-phase voltage transformer.In order to ensure availability, should examine the characteristics of the device for a replacement.
first thing to do is to define the input winding.In step-down transformers, it has the greatest resistance.
Then, plug it in, you can measure the output voltage at idle.The ratio of the input and output EMF is the transformation ratio K. It is also equal to the fraction of I N. / N O., That is, the number of turns in the windings.
You can connect the load as a powerful variable resistor (rheostat) and remove the current-voltage characteristic, the rated current.With increasing load the output voltage drops gradually.
Transformers are not only power, but also measuring.In those cases when it is necessary to define a large amount of current in a circuit using an ammeter.It is switched in series and should have a low resistance in combination with a large cross-section in the magnetic deflection system.Such a device would be too massive and expensive, so use a single-phase current transformers, to eliminate the proportional decrease in value, and submit them to the usual serial ammeters.Calculate amperage is simple, it remains only to apply these factors on the body.
