What is the main purpose of the transformer?
Second, the loss of the transformer
When the primary winding of the transformer is energized, the magnetic flux generated by the coil flows at the core because the core itself is a conductor and the potential is induced on the plane perpendicular to the line of magnetic force. This potential forms a closed loop on the cross section of the core and generates a current, As if a vortex was called "vortex". This "eddy current" increases the loss of the transformer and increases the temperature rise of the transformer's core heating transformer. The loss caused by "eddy currents" is called "iron loss". In addition to the need to use a large number of transformer transformer copper wire, the existence of these copper wire resistance, the current flow through this resistance will consume a certain power, this part of the loss is often turned into heat and consumption, we call this loss " The So the temperature rise of the transformer is mainly caused by iron loss and copper loss.
Since the transformer has an iron loss and a copper loss, its output power is always less than the input power. For this reason, we introduce an efficient parameter to describe this, η = output power / input power.
If the secondary connected to the load, the secondary coil to generate current I2, and thus produce magnetic flux ф2, ф2 and ф1 opposite the direction, played a mutual offset effect, so that the total magnetic flux in the core has been reduced, so that the primary Self-induced voltage E1 reduced, the result is I1 increase, showing the primary current and secondary load are closely related. When the secondary load current increases when I1 increases, ф1 also increases, and ф1 increase part of the part is just to be replaced by ф2 that part of the magnetic flux to keep the total magnetic flux in the core unchanged. If you do not consider the loss of the transformer, you can think of an ideal transformer secondary load power consumption is the primary power from the power supply. The transformer can change the secondary voltage by changing the number of turns of the secondary coil as needed, but can not change the power that allows the load to be consumed.
When a sinusoidal alternating voltage U1 is applied across the primary coil, there is an alternating current I1 in the conductor and an alternating magnetic flux ф1 is generated which forms a closed magnetic path along the core through the primary and secondary windings. The mutual inductance potential U2 is induced in the secondary coil, and ф1 also senses a self-inductance potential E1 on the primary coil. The direction of E1 is opposite to that of the applied voltage U1, which limits the size of I1. In order to maintain the existence of magnetic flux ф1 need to have a certain power consumption, and the transformer itself has a certain loss, although the secondary load is not conne
Transformer is an electrical equipment for electrical energy conversion, it can be a voltage, current AC power into the same frequency of another voltage, current AC power.
Transformers are used in almost all electronic products, and the principle is simple but different depending on the use of different occasions (different purposes) transformer winding process will be different requirements. Transformer functions are: voltage conversion; impedance conversion; isolation; regulator (magnetic saturation transformer), the transformer commonly used core shape generally E-and C-type core.
First, the basic principles of the transformer
