What is the derivation process of the voltage ratio of the primary and secondary coils of the transf

If an alternating current is applied to the primary edge to produce a sinusoidal alternating magnetic field in the core, the primary side induces electromotive force.

e1=-n1*dφ/dt

n1*bm*s*(sinωt)'*d(ωt)/dt-n1*bm*s*ω*cosωt

2*∏*f*n1*bm*s*cosωt；

The same self-induced electromotive force is generated by the payside.

e2=-2*∏*f*n2*bm*s*cosωt；

Their valid values are:

e1=2*√2*∏*f*n1*b*s。

e2=2*√2*∏*f*n2*b*s。

So, e1 e2=n1 n2.

Ratio of original paying side voltage = turn ratio.

Among them, e1 and e2 are the instantaneous values of the original side voltage;

d dt is the rate of flux change;

n1 and n2 are the number of turns of the original pay;

b. BM is the effective value and maximum value of the magnetic induction intensity in the iron core;

s is the core area;

Yes, the angular frequency of the power supply = 2* *f;

f is the mains frequency;

It's pi. For 50 Hz power frequency power supplies there are:

e1=2*√2*∏*50*n1*b*s=100*√2*∏*n1*b*s≈

This formula is the design formula of the power frequency transformer.

The unit of B is Tesla, the unit of S is square meter, and the unit of E is Ford.

If you don't understand these mathematical derivations, you can understand them like this:

As long as there is a varying magnetic field in the core, then all the coils on the core will generate self-induced electromotive force. The new magnetic field generated by the current in the closed loop of self-induced electromotive force is always resistant to changes in the original magnetic field. So a minus sign is added to the formula.

The self-induced electromotive force on the primary side is opposite to the supply voltage, and if there is no copper loss and iron loss on the primary side, the primary current is equal to zero. The reason why there is no-load current on the primary side is because there is a loss. The primary side has to have a no-load current to balance this loss.

After the payside is connected to the load, the magnetic field generated by the payside current destroys the magnetic field balance in the core, so the corresponding value of the primary-side current should be increased to establish a new balance. This is called "mutual inductance". In fact, it is all caused by self-feeling.

Co-directional coupling, lossless, fully coupled, with an infinite number of turns while the proportion is constant.

The primary-side flux chain is 1=I1L1+mi2, the secondary-side is 2=I2L2+mi1 (m is the mutual inductance coefficient), U1=D(1) DT, U2=D(2) DT, and the ratio of the two is U1 U2= 1 2= L1 L2

The turn ratio is equal to the voltage ratio.

The turn ratio is equal to the voltage ratio.

The voltage of the main and auxiliary coils of the transformer is only related to the voltage on the main coil and the number of turns of the main and auxiliary coils, and has nothing to do with the load on the auxiliary coil. Therefore, when the load is increased on the auxiliary coil, the voltage of the main and auxiliary coils remains unchanged.

Due to the parallel load on the secondary coil, the total resistance of the secondary coil is small, and the current increases because the voltage does not change, and the power increases according to P=UI, U does not change, and I increases.

Since the energy on the secondary coil is supplied by the main coil, ideally (excluding the internal losses in the transformer), the electrical energy consumed on the secondary coil is equal to the electrical energy consumed on the main coil. In addition, the internal loss of the transformer is borne by the main and auxiliary coils, so the power on the secondary coil increases, and the power on the main coil also increases.

If the voltage on the main coil remains unchanged and the power increases, the current on the main coil increases.

To sum up: the main coil: the electric sun backup voltage remains unchanged, the current increases, and the power increases.

Secondary coil: the voltage does not change, the current increases, and the power increases.

For the same transformer, the voltage and current of the output winding:

The voltage Changsong ratio is equal to the turns ratio. (The more turns, the higher the voltage) The current ratio is equal to the reciprocal of the turns ratio. (The more turns, the smaller the current) or: voltage, proportional to the number of turns.

Current, anti-resistant Zheng than the number of turns.

If it helps, please give a good review or.

Good luck with your new semester!

1. The ratio of voltage is proportional to the ratio of turns.

2. The ratio of current is inversely proportional to the ratio of turns.

1. To the same transformer.

In return, the voltage and current: voltage ratio of the output winding is equal to the ratio of turns.

2. (The more turns, the higher the voltage) The current ratio is equal to the reciprocal of the turns ratio.

3. (The more turns, the smaller the current) or: voltage, proportional to the number of turns.

4. Current, inversely proportional to the number of turns.

For the same transformer and revoltage, the voltage and current of the output winding system: bai

The voltage ratio is equal to the number of turns du ratio. (The more turns there are, the higher the voltage) the current ratio is equal to the reciprocal of the turns ratio. (The more turns, the smaller the current) or: voltage, proportional to the number of turns.

Current, inversely proportional to the number of turns.

If it helps, please praise or adopt it.

Good luck with your new semester!

The transformer has an input and an output, the input power of the transformer is the actual product of the voltage and current of the input terminal, that is, the original coil, and the output power is the product of the voltage and output current of the output terminal, that is, the auxiliary coil, after the transformer is actually connected to the load. Ideal transformer, since the loss of the transformer is not considered, so the input power of the primary coil is equal to the output power of the secondary coil. In fact, there will be some differences between the two, the input power is generally greater than the output power, the reason is that the actual electronic components are not ideal components, there will be a certain amount of energy loss, the power loss of the transformer is mostly in the magnetic flux leakage, and some are caused by the resistance of the coil.

Since the output power of the transformer is related to the load carried, the actual power is not a definite value, and the output power of the subcoil is the sum of the power of all the electrical appliances connected to the subcoil. In an ideal transformer, the input power of the primary coil is determined by the output power of the secondary coil, and when the actual transformer losses are taken into account, the input power of the primary coil is equal to the output power of the secondary coil plus the losses of the transformer.

Input power primary coil, output power secondary coil.

The input power is for the primary coil and the output power is for the secondary coil.

Input power primary coil, output power secondary coil.

The size of the input power is determined by the size of the output power, and the size is equal, so the input power of the primary coil increases with the increase of the output power of the secondary coil, and it can be seen that the input current of the primary coil increases with the increase of the output current of the secondary coil.

The voltage applied to the original coil is fixed and will not be affected by other factors, and the relationship between voltage, current and power of the ideal transformer is mastered.