A transformer is an electrical apparatus designed to convert alternating current from one voltage to another. It can be designed to step up or step down voltages and works on the magnetic induction principle. When an AC current is passed through the primary coil, an AC magnetic flux is generated in the iron core, causing a voltage (or current) to be induced in the secondary coil. It is composed of an iron core and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary winding, and the remaining windings are called the secondary winding.
Transformer mainly uses the principle of electromagnetic induction to work. The specific process is when an AC voltage U1 is applied to the primary side of the electrical transformer, and the current flowing through the primary winding is I1, the current will generate alternating magnetic flux in the iron core, which makes the primary winding and the secondary winding electromagnetically connections.
According to the principle of electromagnetic induction, the electromotive force will be induced when the alternating magnetic flux passes through these two windings. Its magnitude is proportional to the number of winding turns and the maximum value of the main magnetic flux. The voltage on the side with more winding turns is higher, and the voltage on the side with less winding turns is lower. When the secondary side of the transformer is open, that is, when the transformer is no-load, the voltage at the primary and secondary terminals is proportional to the number of turns of the primary and secondary windings. That is, U1/U2=N1/N2, but the primary and secondary frequencies are consistent, so as to realize the voltage change. The working principle of the transformer can be understood from the figure below.
Isolation transformer refers to a transformer with electrical isolation between the input winding and the output winding. It is widely used in the electronic industry or industrial and mining enterprises, machine tools and mechanical equipment in the general circuit control power supply, safety lighting and indicator power. It can completely insulate the electrical on the primary side and the secondary side, and also isolate the circuit. In addition, the high-frequency loss of its iron core is used to prevent high-frequency clutter from entering the control loop. Using an isolation transformer to suspend the secondary to the ground can only be used in occasions where the power supply range is small and the line is short. At this time, the capacitance current of the system to ground is too small to cause personal injury. Another important role is to protect personal safety! It can isolate people from dangerous voltages.
Toroidal transformer is a kind of step-up & step-down transformer power supply, which has the advantages of small volume, low noise, less heat and high performance. Generally, we use a variety of voltages, such as 220V for domestic lighting, 36V for industrial safety lighting, and the voltage of the welding machine needs to be adjusted. These cannot be separated from the toroidal transformer, which can step down the voltage we need through the principle of electromagnetic mutual inductance of the main and auxiliary coils. But how to improve the conversion efficiency of toroidal transformers has been a problem for many people. In fact, the conversion rate of a toroidal transformer is determined by the transformer's power, production materials, and its work site.
Control transformer is a small dry-type transformer, which is mainly used to change the voltage of AC power. It is wound by an iron core and a coil. It can change not only the voltage of the alternating current, but also the impedance. When the design power is not exceeded, the current can also be changed. In different environments, the transformer also has different applications. Generally, it is used as a control lighting and indicator light source for electrical appliances in machine tools and mechanical equipment. The multi tapped control transformer can also be used in the chemical industry as a rectifier transformer. At this time, it is only required to rewire the adjustment taps of the control transformer, cut off all power to the equipment, and then adjust the voltage to the control transformer with voltage regulating equipment on both sides, so that it can be used in the chemical industry.
Autotransformer is a transformer whose windings are primary and secondary in the same winding, the primary and secondary windings are directly connected in series, and the transformer is self-coupled. Ordinary transformers transfer energy through electromagnetic coupling of primary and secondary coils, and there is no direct electrical connection between primary and secondary, while autotransformer has direct electrical connection between primary and secondary, and its low voltage coil is part of high voltage coil. Autotransformers are also used as protection equipment for communication lines.
Since the calculated capacity of an autotransformer is less than the rated capacity. Therefore, for the same rated capacity, the main dimensions of the autotransformer are smaller and the effective material (silicon steel sheet and conductors) and the construction material (steel) are reduced accordingly, thus reducing the cost. The reduction of effective materials leads to a corresponding reduction of copper and iron consumption, so the efficiency of the autotransformer is higher. Also, due to the reduction of the main dimensions and mass, it is possible to manufacture transformers with larger capacities per unit under tolerable transportation conditions.
There are many types of power transformers, but each type of transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. Therefore, the use of each transformer can ensure the safety of electricity. By changing the AC voltage without changing the power source, the current can be changed, which essentially enables people to use electricity safely.
The transformer can make voltage step up & down. We often use various voltages. For example, we need different voltages for household lighting power and industrial safety power. All of these are inseparable from the transformer. Using the transformer, we can reduce the voltage to the required voltage through the principle of electromagnetic mutual inductance, and reduce the voltage loss.
This function is most commonly used in electronic circuits. Generally speaking, electronic factories will use transformers for impedance matching to make the signal flow smoothly. Therefore, companies that require different voltages in the same environment can manufacture multi-winding transformers to satisfy the daily needs of workers.
Before the step up or step down transformer is used, it should be fully tested to ensure the safe and stable operation. The detection of transformer before operation mainly includes the following points.