Electrician: Basic knowledge of 16 transformers, the old master said that 12 is already very good! (II)
Release time:
2023-02-22
7. How does the regulator adjust the pressure?
The structure of the voltage regulator is the same as that of the autotransformer, except that the iron core is made into a toroidal coil and wound on the toroidal iron core. The secondary coil tap uses a sliding brush contact to make the contact slide along the coil surface to achieve smooth adjustment voltage.
8. What is the current relationship between the primary coil and the secondary coil of the transformer?
When the transformer is operated with a load, a 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 civilian secondary coil is inversely proportional to the number of turns, the current is small on the side with more turns, and the current is large on the side with fewer turns, which can be expressed by the following formula: primary coil current/secondary coil current = secondary coil turns/primary coil turns. 9, what is the voltage change rate of the transformer?
The voltage change rate of the voltage 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 drop. Comparing the drop voltage value with the rated voltage value, the percentage is the voltage change rate, which can be expressed by the formula. Voltage change rate =[(secondary rated voltage-load terminal voltage)/secondary rated voltage] × 100. Usually the power transformer, connected to the rated load, the voltage change rate of 4 ~ 6%.
10. How to ensure that the transformer has a rated voltage output?
The voltage is too high or too low will affect the normal operation and service life of the transformer, so the voltage must be regulated. The method of voltage regulation is to lead out several taps in the primary coil and connect them at the beginning of the tap. At the beginning of the tap, the number of turns of the coil is changed by rotating the contact. As long as the position of the tap changer is turned, the required rated voltage value can be obtained. It should be noted that voltage regulation should usually be carried out after cutting off the load connected to the transformer.
11. What is the commonly used small transformer? In what occasions?
Small transformers refer to single-phase transformers with a capacity of less than 1 kVA, mostly used as power transformers for electrical equipment control, power transformers for electronic equipment and power transformers for safety lighting.
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