数据中心电气基础知识(数据中心供电逻辑图)

2017 Basic Electrical Knowledge: Basic Knowledge of Electric Motors

1. Basic Knowledge of Three-Phase Asynchronous Motors

1. According to the center height, the motor is divided into: small (80-315mm), medium (355-630mm), large (above 630mm)

2. According to the installation method, it is divided into: horizontal, vertical Type, vertical and horizontal purposes

3. The following data are mainly marked on the AC asynchronous motor nameplate, and their meanings are explained as follows: (1) Rated power (P): is the motor shaft output power on. When the motor is running under rated conditions, the mechanical power that its shaft can output is called rated power. Refers to the mechanical load exceeding the rated power of the motor. At this time, the electromagnetic torque is less than the load torque, the slip rate increases, the stator current exceeds the rated value, and the motor temperature is too high. The reasons for overloading are changes in the process conditions of the production machinery, the transmission belt is too tight, the center of the unit is not aligned, the shaft rotates inflexibly, and the mechanical part is stuck, etc. To this end, efforts should be made to reduce the load, adjust the belt tightness, overhaul mechanical equipment, and eliminate jamming faults.

(2) Rated voltage: refers to the line voltage applied to the winding. The rated voltage is the line voltage value that should be applied to the stator winding of the motor under rated operating conditions. The rated voltage of Y series motors is 380V. The stator windings of all motors with power less than 3KW are star-connected, and those above 4KW are delta-connected.

(3) Rated current: stator winding wire current. When the motor is supplied with a rated voltage and outputs rated power on its shaft, the line current value that the stator draws from the power source is called the rated current.

(4) Rated speed (r/min): the number of revolutions under rated load. The speed when running under rated conditions is called rated speed.

(5) Insulation level: refers to the maximum temperature that the motor insulation material can withstand. B pole 130K (65℃ + ambient temperature); F grade 155K; the maximum bearing operating temperature is 80℃. If accurate and reliable measurement is required, an infrared thermometer can be used to measure the actual temperature. Rough detection method: The operating temperature of the motor is too high, which seriously affects its service life and safe operation. If you touch the case with your hand and it feels hot, you can continue to touch it for a short period of time, and the temperature will no longer rise, and it will not be overheated; if your hand is hot, retract it immediately, and the small water droplets will make a "wisp" sound when it drips, and it will evaporate immediately , the motor may be overheated.

(6) Working quota: that is, the allowed working mode of the motor. Refers to the way the motor operates. Generally divided into "continuous" (code-named S1), "short-time" (code-named S2), and "intermittent" (code-named S3)

(7) Winding connection: Δ or Y connection , corresponding to the rated voltage.

　⑻Protection level:

Refers to the level of protection that prevents the human body from contacting the rotating parts of the motor, the live parts in the motor, and prevents solid foreign objects from entering the motor.

The meaning of the protection mark IP44:

IP - characteristic letters, the abbreviation of "International Protection";

1mm solids entering the motor); Level 4 waterproof (splashing water from any direction should have no harmful effects).

⑼. LW value:

The LW value refers to the total noise level of the motor. The smaller the LW value, the lower the noise of the motor operation. The unit of noise is dB.

　(10)Heat dissipation channel:

When the motor is exposed to the scorching sun or operates in a place with poor ventilation and high temperature, efforts should be made to improve its working environment. For example, build a shed to provide shade, remove dirt from the air vents and casing, and improve the self-cooling conditions of the motor.

For motors that start frequently or run forward and reverse, because the intermittent time is very short, the heat generated by the larger starting current has no time to dissipate. The temperature rise of multiple starts is superimposed, which is equivalent to several times the current and a larger amount. Prolonged overload.

4. Model:

For example, "Y" in Y112M-4 means Y series squirrel cage asynchronous motor (YR means wound asynchronous motor), and "112" means the motor's The center height is 112mm, "M" means medium base (L means long base, S means short base), and "4" means 4-pole motor.

Some motor models also have a digit after the base code, which represents the core number. For example, the "2" after S in the Y132S2-2 model indicates the length of the No. 2 core (1 is the length of the No. 1 core).

　2. Safe use of electricity

　1. Safety voltage levels: 6V, 12V, 24V, 36V, 42V, double-winding transformer used

　2. Current Degree of damage to the human body: A. Current intensity, current properties (40-60HZ), current path, current duration

3. Leakage protector: 30Ma

3. Loss of pressure delay Time protection (drawing)

Class A equipment 1 second, Class B equipment 0.5 seconds; such as 1 ion membrane circulating alkali pump, pure water pump, light salt water pump; new chlorine hydrogen vacuum pump, chlorine water circulation Pump; evaporated alkali feeding pump, etc.

The electrical automation major includes circuits, digital circuit basics, a brief tutorial on the basics of analog electronic technology, electrical and electronic technology, automatic control technology, sensor applications, and motor drag and control technology, factory power supply and distribution technology, PLC application technology, power electronics technology, microcontroller and interface technology, small measurement and control product development, advanced electrician comprehensive training, innovation and practical training, and electrical control comprehensive training.

The major of electrical automation technology is to cultivate certain basic knowledge of electronic technology, microcomputer control technology and computer network technology.

Be familiar with the working principles of commonly used electrical equipment, master the basic principles and methods of applying computer technology to achieve electrical control, and have strong automatic control system operation, maintenance, system integration and certain engineering design capabilities and enterprise management Highly skilled technical application professionals.

Extended information:

The Electrical Automation Technology Major was founded in 2011. After several years of development, the number of enrolled students has reached 450. There are currently 23 full-time and part-time teachers. Among them, there are 9 professors and associate professors, 8 doctors and masters, and 9 dual-qualified teachers.

The college has an electrical training center covering an area of ​​1,300 square meters. The total value of experimental training equipment is 2.3 million yuan, which can fully meet the needs of electrical engineering, analog, digital electronic technology, PLC application technology, electrical control technology, and single-chip microcomputer. Practical training teaching needs such as applied technology, electrical drawing CAD, etc., as well as intensive skill training and extracurricular training for students.

Through school-enterprise cooperation, 6 off-campus training bases have been established with many well-known companies in Chengdu, Deyang and Liangshan Prefecture. The traditional industrial structure and industrial transformation and upgrading, as well as the continuous development of smart buildings and smart transportation, have led to the vigorous development of electrical automation technology and provided a large number of employment opportunities for graduates of this major.

Reference source: People's Daily Online - Electrical Automation Technology Major