Electric and electrical control technology, driving the future

Aug 17, 2023

The course 'Motor and Electrical Control Technology' is one of the core courses in the field of mechatronics and electrical automation, as well as one of the mandatory courses for mechanical manufacturing and CNC majors.

There are many classification methods for motors, and commonly used classification methods include: according to functional purposes, they can be divided into four categories: generators, motors, and control motors; According to the structure, speed, and motion mode of the motor, it can be divided into transformers, rotating motors, and linear motors.

A transformer is a stationary motor. Rotating motors can be divided into two categories based on the type of power current: DC motors and AC motors. AC motors can also be divided into two categories: synchronous motors and asynchronous motors.

A transformer is a stationary motor that uses the principle of electromagnetic induction to convert alternating current of one voltage into alternating current of another voltage with the same frequency.

(1) Ferromagnetic materials have high conductivity, magnetization, magnetic saturation, and hysteresis, so most electrical equipment A6 uses ferromagnetic materials to form magnetic circuits.


(2) Ohm's law of magnetic circuit, but due to the non constant permeability of magnetic substances, Pn μ The magnetic resistance decreases with the saturation of the magnetic circuit, so it increases with the saturation of the magnetic circuit. Therefore, in nonlinear magnetic circuits, the Ohm's law of the magnetic circuit cannot be used for quantitative calculations, and it is commonly used for qualitative analysis.

(3) For AC iron core coils, when the number of turns N and the power frequency f are constant, the magnitude of the main magnetic flux amplitude in the iron core depends on the effective value of the applied voltage of the excitation coil, and is independent of the material size of the iron core.


(4) All transformers are composed of two parts: an iron core and a winding. Transformers have the function of changing voltage, current, and impedance.

(5) When current flows into (or out of) two coils and the direction of the magnetic flux generated is the same, the two inflow ends are called the same polarity end (homonymous end). Judgment method: If you know the direction of deviation, use the definition to judge; If you do not know the winding direction, use AC or DC methods for measurement before making a judgment.

(6) There are 5 standard connections for three-phase dual winding power transformers: Y, yn0; YN, y0; Y. Y0; Y. ,; Y. D1l.

(7) When using an autotransformer, attention should be paid to: 1. Do not make mistakes in the primary and secondary windings; 2. The live wire and zero wire cannot be connected in reverse. 3. Adjust the voltage from the zero position.


(8) It is strictly prohibited to operate the secondary winding of the current transformer in open circuit and the secondary winding of the voltage transformer in short circuit.

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