You get a bonus - 1 coin for daily activity. Now you have 1 coin

Transformer external characteristic

Lecture



The dependence of the secondary voltage U2 on the current I2 at a fixed voltage U1, with cosφ = const

Transformer external characteristic

The higher the load current I2, the lower the voltage U2, but within Transformer external characteristic changes, that is, below by a few%.

Load characteristics

Transformer external characteristic

P2 - active power given to the consumer,
P1 - active power received from the network source
Transformer external characteristic low-power transformers
electric furnace transformers have Transformer external characteristic

Transformer external characteristic

from the experience with the load

Transformer external characteristic
Transformer external characteristic

Transformer external characteristic - electrical losses
Transformer external characteristic - magnetic losses depend on the load factor

Transformer external characteristic

The external characteristic of the transformer is the dependence of the voltage of the secondary winding U 2 on the current I 2 . If we ignore the no-load current, then the equivalent circuit of a transformer in nominal mode takes the form shown in Figure 1.

Transformer external characteristic
Figure 1 The equivalent circuit of a transformer for the construction of its external characteristics

Considering that Z kz = R kz + jX kz , the voltage on the secondary winding of the transformer can be expressed as follows:

Transformer external characteristic (one)

Construct a vector diagram relative to the current vector Transformer external characteristic as shown in Figure 2.

Transformer external characteristic
Figure 2 Vector diagram of currents and voltages of the transformer secondary winding

If the load resistance Transformer external characteristic active then the voltage Transformer external characteristic coincides in phase with the current Transformer external characteristic . Amount Transformer external characteristic . The magnitude of the applied voltage U 1 = const , it is obvious that when the current changes Transformer external characteristic , the voltage drop Δ U on the internal resistance of the transformer will also change. That is, the external characteristic has a falling character, as shown in Fig. 2.25.


Comments


To leave a comment
If you have any suggestion, idea, thanks or comment, feel free to write. We really value feedback and are glad to hear your opinion.
To reply

Electrical Engineering, Circuit design

Terms: Electrical Engineering, Circuit design