Explanation of the most popular Electrotechnical t

2022-08-23
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Explanation of common Electrotechnical terms

to learn electrotechnics well, it is necessary to understand the concepts of some physical quantities in Electrotechnics. Therefore, I sum up the vocabulary of some commonly used Electrotechnical names and instruments that can have relatively close initial running speed corresponding to the set frequency and make notes:

1, resistivity --- also known as resistance coefficient or specific resistance. It is a physical quantity to measure the conductivity of a substance. It is expressed in letters, and the unit is Ohm * millimeter square/meter. Numerically, it is equal to the resistance value of a wire with a length of 1 meter and a cross-sectional area of 1 mm2 made of that material at the temperature of 20c. The higher the resistivity, the lower the conductivity

2. Temperature coefficient of resistance ---- refers to the physical quantity that the resistivity of a substance changes with temperature. Its value is equal to the ratio of the increase of resistivity to the original resistivity when the temperature rises by 1C. It is usually expressed in letters, and the unit is 1/C

3. Conductivity ---- the ability of an object to conduct current is called conductivity. In a DC circuit, the value of conductance is the reciprocal of the resistance value, represented by the letter G, and the unit is Siemens

4. Conductivity ---- also known as conductivity coefficient, is also a physical quantity to measure the conductivity of substances. Size is the reciprocal of resistivity in numerical value, expressed in letters, and the unit is meter/ohm * millimeter square

5. Electromotive force ---- the potential difference caused by the conversion of other forms of energy into electrical energy in the circuit, which is called electromotive force or EMF for short. Represented by the letter E, in volts

6. Self induction ---- when the current in the closed circuit changes, the magnetic flux passing through the circuit itself generated by this current also changes. Therefore, the induced electromotive force in the circuit is also called self induction phenomenon, which is called self induction electromotive force

7. Mutual inductance ---- if two coils are close to each other, part of the magnetic flux generated by the current in the first coil is linked with the second coil. When the current in the first coil changes, the magnetic flux between it and the loop chain of the second coil also changes, and the induced electromotive force is generated in the second coil. This phenomenon is called mutual inductance

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8. Inductance - a general term for self inductance and mutual inductance

9, inductive reactance ---- when the AC current passes through the circuit with inductance, the inductance has the effect of blocking the AC current passing. This effect is called inductive reactance, expressed in LX, lx=2 fl.

10, capacitive reactance ---- when the AC current passes through the circuit with capacitance, the capacitance has the effect of blocking the AC current passing. This effect is called capacitive reactance, expressed in CX, cx=1/12 FC

11. Pulsating current ---- the current whose magnitude changes with time and whose direction remains the same is called pulsating current

12. Amplitude ---- the maximum value of alternating current in a cycle is called amplitude

13. Average value ---- the average value of alternating current refers to the ratio of the total charge flowing through the circuit in a certain period of time to that period of time. The average value of sinusoidal quantity usually refers to the average value within half a cycle, and its relationship with amplitude value: average value =0.637* amplitude value

14. Effective value ---- in two identical resistance devices, direct current and alternating current pass through respectively. If the heat they emit is equal after the same time, the magnitude of this direct current is taken as the effective value of this alternating current. The effective value of sinusoidal current is equal to 0.707 times its maximum value

15. Active power ---- also known as average power. The instantaneous power of alternating current is not a constant value. The average value of power in a cycle is called active power. It refers to the power consumed by the resistance part of the circuit, expressed in the letter P, in watts

16. Apparent power ---- in a circuit with resistance and reactance, the product of voltage and current is called apparent power, which is represented by the letter PS, and the unit is watt

17. Reactive power ---- in the circuit with inductance and capacitance, these energy storage elements store the energy that turns the power supply energy into a magnetic field (or electric field) in the half cycle time, and return the stored magnetic field (or electric field) energy to the power supply in the other half cycle time. They only exchange energy with the power supply, and do not really consume energy. We call the amplitude value of the rate of energy exchange with the power supply reactive power. It is represented by the letter Q, and the unit is Zhi

18. Power factor ---- in DC circuit, voltage multiplied by current is active power. However, in an AC circuit, voltage multiplied by current is the apparent power, and part of the power that can do work (i.e. active power) will be less than the apparent power. The ratio of active power to apparent power is called power factor and is expressed in COS

19. Phase voltage ---- the voltage between three-phase transmission line (live line) and neutral line is called phase voltage

20. Line voltage ---- the voltage between lines (live lines) of three-phase transmission line is called line voltage, and the size of line voltage is 1.73 times of phase voltage

21. Phasor ---- in Electrotechnics, the vector used to represent the magnitude and phase of sinusoidal quantity is called phasor, also known as vector

22. Magnetic flux ---- the product of magnetic induction intensity and the area perpendicular to the direction of the magnetic field is called magnetic flux, which is expressed in letters and the unit is Maxwell

23. Magnetic flux density ---- the size of the magnetic flux passing through per unit area is called magnetic flux density, which is represented by the letter B. the magnetic flux density and the magnetic field induction intensity are equal in value

24. Magnetoresistance ---- similar to the meaning of resistance, magnetoresistance refers to the blocking effect of magnetic circuit on magnetic flux. The symbol RM indicates that the development prospect of China's plastic extruder market is good, and the unit is 1/Heng

25. Permeability ---- also known as the magnetic conductivity coefficient, is a coefficient to measure the magnetic conductivity of a substance. It is expressed in letters, and the unit is Heng/m

26. Hysteresis ---- in the process of repeated magnetization, the change of its magnetic induction intensity always lags behind its magnetic field intensity. This phenomenon is called hysteresis

27. Hysteresis loop ---- in a magnetic field, the relationship between the magnetic induction intensity and the magnetic field intensity of a ferromagnet can be expressed by a curve. When the magnetized magnetic field changes periodically, the relationship between the magnetic induction intensity and the magnetic field intensity in a ferromagnet is a closed line, which is called a hysteresis loop

28. Basic magnetization curve ---- the shape of the hysteresis loop of ferromagnet is related to the maximum value of magnetic induction (or magnetic field intensity). When drawing the hysteresis loop, if the maximum value of magnetic induction (or magnetic field intensity) is taken as a different value, a series of hysteresis loops will be obtained. The curve connecting the vertices of these loops is called the basic magnetization curve

29. Hysteresis loss ---- the ferromagnet placed in an alternating magnetic field produces some power loss due to hysteresis, which makes the ferromagnet heat up. This loss is called hysteresis loss

30, breakdown --- the phenomenon of violent discharge or conduction of insulating materials under the action of electric field is called breakdown

31. Dielectric constant --- also known as dielectric constant, dielectric coefficient or permittivity, it is a coefficient indicating the characteristics of insulation capacity, expressed in letters, and the unit is method/meter

32. Electromagnetic induction --- when the magnetic flux linked to a conductor changes, electromotive force appears in the conductor. This phenomenon is called electromagnetic induction

33. Skin effect --- also known as skin effect. When high-frequency current passes through the conductor, the current will be concentrated on the surface of the conductor. This phenomenon is called skin effect, which is called the silver light group's continuous efforts to strengthen the cultivation of high skilled talents

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