How to calculate the transformation ratio

The coefficient of transformation is the main characteristic of the transformer. It shows how to change the main parameters of the electrical current after it passes through the device. When the ratio of transformation of greater than 1 is called a step – down transformer, if less increase.

You will need

• - transformer;
• - AC power source;
• tester;
• calculator.

Instruction

1. Take an ordinary transformer. It consists of two coils. Find the number of turns of coil N1 and N2, which are the basis of the transformer and connected to the magnetic circuit. Determine the coefficient of transformation k. To do this, divide the number of turns of the primary coil N1, which is connected to the current source, the number of turns of the secondary coil N2 connects to load: k=N1/N2.
2. Example. Winding of the transformer connected to the current source, has 200 turns and the other winding of 1200 turns. Determine the coefficient of transformation and the type of the transformer. Find the primary and secondary windings. The primary is the one that is connected to the current source, it has 200 turns. The secondary winding is respectively 1200 turns. Calculate the coefficient of transformation according to the formula: k=N1/N2=200/1200=1/6≈0,167. Transformer increases.
3. Measure electromotive force (EMF) on both windings of the transformer ε1 and ε2, if it is not possible to know the number of turns in them. To do this, connect the primary winding of the transformer to the power supply. This mode is called idle. With a tester find the voltage across the primary and secondary winding. It will be equal to the EMF of each winding. Keep in mind that energy losses due to the resistance of the windings are negligibly small. Calculate the rate of transformation the ratio of the EMF of the primary and secondary winding: k= ε1/ε2.
4. Example. The voltage across the primary winding after the connection to the source of current is 220 V. an open On the secondary winding voltage is 55 V. Find the coefficient of transformation. The transformer is idling, so the voltage on the windings count is equal to the EMF. Calculate the coefficient of transformation according to the formula: k=ε1/ε2=220/55=4.
5. Find the coefficient of transformation of the working of the transformer when the secondary winding is attached to the user. Calculate it by dividing the current in the primary winding I1, the current I2 in the secondary winding. The current measure, adding sequentially windings tester, switched to the operation mode of the ammeter: k=I1/I2.