Product Features

1. The SBF triple frequency transformer is simple to operate and reliable in performance



2. It can well meet the needs of induced voltage withstand tests for transformers and instrument transformers



Transformers are used in almost all electronic products. Their principle is simple, but depending on the application (different uses), the winding process of transformers will have different requirements. The main functions of transformers include: voltage transformation; impedance transformation; isolation; voltage stabilization (magnetic saturation transformer), etc. The commonly used core shapes for transformers are generally E-type and C-type cores.

I. Basic Principle of Transformers



When a sinusoidal AC voltage U1 is applied across the primary coil, an alternating current I1 flows in the wire and generates an alternating magnetic flux φ1, which passes through the primary and secondary coils along the core, forming a closed magnetic circuit. A mutual induced potential U2 is induced in the secondary coil, and at the same time, φ1 also induces a self-induced potential E1 in the primary coil. The direction of E1 is opposite to that of the applied voltage U1, and its magnitude is similar, thereby limiting the magnitude of I1. To maintain the existence of the magnetic flux φ1, a certain amount of electrical energy consumption is required, and the transformer itself also has certain losses. Even when the secondary is not connected to a load, there is still a certain current in the primary coil, which is called the "no-load current".



If a load is connected to the secondary, the secondary coil generates a current I2, which in turn produces a magnetic flux φ2. The direction of φ2 is opposite to that of φ1, which has a canceling effect, reducing the total magnetic flux in the core, thereby reducing the primary self-induced voltage E1. As a result, I1 increases. It can be seen that the primary current is closely related to the secondary load. When the secondary load current increases, I1 increases, and φ1 also increases. Moreover, the increase in φ1 exactly compensates for the part of the magnetic flux canceled by φ2, so as to keep the total magnetic flux in the core unchanged. If the losses of the transformer are not considered, it can be considered that the power consumed by the secondary load of an ideal transformer is exactly the electrical power that the primary obtains from the power source. A transformer can change the secondary voltage by changing the number of turns of the secondary coil as needed, but it cannot change the power that the load is allowed to consume.



II. Transformer Losses



When the primary winding of a transformer is energized, the magnetic flux generated by the coil flows in the core. Since the core itself is also a conductor, an induced potential is generated on the plane perpendicular to the magnetic field lines. This potential forms a closed circuit on the cross-section of the core and generates a current, which is like a vortex, so it is called "eddy current". This "eddy current" increases the losses of the transformer, and causes the core of the transformer to heat up, increasing the temperature rise of the transformer. The loss caused by "eddy current" is called "iron loss". In addition, a large amount of copper wire is needed to wind the transformer. These copper conductors have resistance, and when current flows through them, this resistance consumes a certain amount of power. This part of the loss often turns into heat and is consumed, and we call this loss "copper loss". Therefore, the temperature rise of a transformer is mainly caused by iron loss and copper loss.



Since transformers have iron loss and copper loss, their output power is always less than the input power. For this reason, we introduce an efficiency parameter to describe this, η = output power / input power.