1. What is a transformer?
In an AC circuit, the device that raises or lowers the voltage is called a transformer. The transformer can convert any value of the voltage into the voltage value we need at the same frequency to meet the requirements of the transmission, distribution and use of the power. For example, the electricity generated by the power plant has a low voltage level, and the voltage must be raised to be transported to a remote power consumption area. The power supply area must be turned down to a suitable voltage level to supply power equipment and daily power. Equipment.
2. What types of transformers are there?
There are single-phase and three-phase transformers according to the number of phases. According to the use, there are power transformers, special power transformers, voltage regulating transformers, measuring transformers (voltage transformers, current transformers), small power transformers (for small power equipment), safety transformers, core and shell according to structure. Two. The coil has two windings and multiple windings, and the autotransformer is divided into oil immersed and air cooled by cooling.
3. What is the voltage change rate of the transformer?
The voltage change rate of the regulator is one of the main performance indicators of the transformer. When the transformer supplies power to the load, the voltage at the load end of the transformer will inevitably fall. The voltage value to be dropped is compared with the rated voltage value. The percentage, that is, the rate of voltage change, can be expressed by the formula; the voltage change rate = [(secondary rated voltage) - load terminal voltage) / secondary rated voltage] × 100. The normal power transformer, when connected to the rated load, has a voltage change rate of 4 to 6.
4. How to ensure that the transformer has a rated voltage output?
Too high or too low voltage will affect the normal operation and service life of the transformer, so it must be regulated. The method of voltage regulation is to draw several taps in the primary coil, which is connected to the beginning of the tap, and the tapping of the contacts is used to change the number of turns of the coil. As long as the position of the tap-changer is turned, the required voltage rating can be obtained. It should be noted that the voltage regulation should normally be carried out after the load connected to the transformer is cut off.
5. How does the transformer change the voltage?
The transformer is made according to electromagnetic induction. It consists of an iron core laminated with silicon steel sheets (or silicon steel sheets) and two sets of coils wound around the iron core. The iron core and the coil are insulated from each other without any electrical connection, as shown. The coil that connects the transformer to the power supply side is called the primary coil (or the primary side), and the coil that connects the transformer to the powered device is called the secondary coil (or secondary side). When the primary coil of the transformer is connected to an AC power source, a varying magnetic field line is generated in the core. Since the secondary coil is wound on the same core, the magnetic line cuts the secondary coil, and an induced electromotive force is inevitably generated on the secondary coil, so that a voltage appears across the coil. Since the magnetic lines of force are alternating, the voltage of the secondary coil is also alternating. And the frequency is exactly the same as the power frequency. It is proved by theory that the voltage ratio of the primary coil to the secondary coil of the transformer and the ratio of the turns of the primary coil to the secondary coil can be expressed by the following formula: primary coil voltage / secondary coil voltage = primary coil turns / secondary coil turns Explain that the more turns, the higher the voltage. Therefore, it can be seen that the secondary coil is less than the primary coil and is the step-down transformer. The opposite is the step-up transformer.
6. What is the use of transformer oil?
The role of transformer oil is: (1) insulation. (2) Heat dissipation. (3) Eliminate the arc effect.
7. What parts of the transformer are made up of?
The transformer is mainly composed of iron core and coil, in addition to the fuel tank, oil pillow, insulating sleeve and the beginning of the tap.
8. What is an autotransformer?
The autotransformer has only one set of coils, and the secondary coil is tapped from the primary coil. Its power transmission, in addition to electromagnetic induction transmission, also has electrical transmission. The number of silicon steel sheets and copper wires of this transformer is larger than that of a general transformer. Less, often used to regulate voltage.
9. How is the regulator regulated?
The regulator is constructed in the same way as an autotransformer except that the core is wound into a toroidal core. The secondary coil tap uses a slidable brush contact to make the contact slide along the surface of the coil to achieve a smooth adjustment voltage.
10. What is the current relationship between the primary and secondary coils of the transformer?
When the transformer is running with a load, the change in the secondary coil current causes a corresponding change in the primary coil current. According to the principle of magnetic potential balance, the current of the primary secondary coil is inversely proportional to the number of turns of the coil. The current on the side with a large number of turns is small, and the current on the side with a small number of turns is large. It can be expressed by the following formula: primary coil current/time Stage coil current = secondary coil turns / primary coil turns