Ms. Shen’s best friend HH doesn’t like summer very much. The first reason is that HH ’s sweat glands are special, and basically does not sweat on hot days, so it feels particularly uncomfortable; the second reason is that HH ’s mosquito relationship is particularly good, and sometimes it will be caused by a single mosquito. Didn’t sleep well. Someone gave his best friend HH a “bad” idea: turn on the air conditioner and put on a quilt when sleeping in summer. What’s interesting is that this “bad” idea is quite effective. Ms. Shen used this method to avoid the scorching heat and deal with mosquitoes during business trips in summer. Today we will talk about inverter motors from the inverter air conditioner.
Inverter and fixed frequency air conditioner
The inverter air conditioner can control and adjust the speed of the compressor through the frequency converter, so that it is always at the optimal speed state, that is, the compressor can be moderately adjusted in temperature when it is turned on for a long time: if there is no need for a lot of cooling or heating in the room, the air conditioner will It will run at a low frequency and intelligently control the temperature constantly. The fixed-frequency air conditioner needs to continuously start and stop the compressor to achieve constant temperature control, and the temperature fluctuates greatly.
Frequency conversion speed regulation motor characteristics
The above motors for frequency conversion air conditioners are typical applications of frequency conversion speed regulation motors. Compared with ordinary motors, frequency conversion speed regulation motors for general purposes have the following characteristics: frequency conversion motors
●Adopt frequency converter to supply power.
● Change the traditional motor fan into an independent fan.
●The insulation performance requirement of the motor winding is higher than that of ordinary motors.
●Because of the particularity of the frequency conversion of the motor, motor resonance is prone to occur during the start-up process of the variable frequency speed regulating motor. The rigidity of the motor components and the whole should be fully considered to prevent the vibration and noise problems of the motor.
● Insulation grade generally choose F grade or higher, strengthen the ground insulation and inter-turn insulation strength, in order to improve the ability of the motor insulation to withstand the impact voltage.
●Special magnet wires for frequency conversion motors are used, especially for high-power motors, the requirements in this aspect are more stringent due to different application places.
●Forced ventilation cooling requirements. Compared with ordinary motors, the speed of the motor is not unique. If the self-contained fan is used for cooling, the ventilation and heat dissipation effect of the motor will be greatly reduced; therefore, an independent ventilation and heat dissipation scheme should be adopted.
In general, the axial flow is used to strengthen the ventilation with the fan; special attention should be paid to the fact that the fan cannot share the power supply with the motor. The fan should be started before the motor is started, and the motor power should be turned off when the motor is stopped.
●Shaft current problem. Bearing insulation measures should be adopted for motors with a capacity exceeding 160KW . Measures such as insulating bearings, insulating bearing chambers, and adding leakage carbon brushes can be used.
●Grease. For constant power variable frequency motors, when the speed reaches 2P motor speed, special grease with high temperature resistance should be used to prevent the loss of bearing grease due to temperature rise, which will cause bearing damage and winding burnout.
●Manufacturing process control. Vacuum pressure varnish manufacturing process and special insulation structure are adopted to ensure the insulation withstand voltage and mechanical strength of the electrical winding.
●Rotor dynamic balance control to improve the machining accuracy of parts, select bearings with high performance requirements, and can run at high speed.
Frequency conversion motor test
Generally need to use frequency converter power supply. Because the output frequency of the inverter has a wide range of variation, and the output PWM wave contains rich harmonics, the traditional transformer and power meter can no longer meet the measurement needs of the test, and the general Hall voltage and current sensors do not directly affect The angle difference index of power accuracy measurement is controlled and nominal, and the frequency conversion power analyzer and frequency conversion power sensor with clear ratio difference and angle difference index should be used as the main power measurement instrument.
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Post time:
May-11-2023