Inverter motor: principle of operation, advantages and disadvantages of an electric motor

Mainly, an inverter motor differs from a conventional electric motor in that it has no brushes. Units are used in refrigerators, automatic washing machines, air conditioners. The converter, which acts as a power source for the motor, converts the alternating voltage into direct voltage. Received constant current converted to alternating current of specified frequency

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The device of inverter type motors

The main parts are directly the motor and the frequency converter, which ensures the principle of the motor. The frequency converter is used to regulate the speed of the motor by creating the required voltage frequency at the output of the converter. The range of the output frequency in converters varies widely, and its limit values ​​can exceed the frequency of the supply network by tens of times.

In the inverter converter, a double voltage conversion takes place. The sinusoidal voltage at the input of the converter is first rectified in the rectifier unit, filtered and smoothed by the capacitors of the electric filter. Further, from the obtained constant voltage

using control circuits and output electronic keys set a sequence of controlled pulses of the desired shape and frequency. With the help of pulses, an alternating voltage of the required magnitude and frequency is generated, which is formed at the output of the converter.

Sinusoidal alternating current generated by the converter is formed on the windings of the electric motor as a frequency-pulse or pulse width modulation. Electronic switches for converters are, for example, off thyristors GTO, their upgraded versions IGCT, SGCT, GCT and IGBT transistors.

The motor consists of a stator with small field windings, the number of which is a multiple of three. A rotor with permanent magnets attached to it rotates in the stator. The number of magnets is three times less than the number of field windings. There is no collector-brush assembly in such an engine.

All this is an inverter electric motor, the principle of operation of which is based on interaction stator and rotor magnetic fields. The rotating electromagnetic field of the stator created by the converter makes the frequency rotor rotate at the same frequency. So, the motor is controlled by an inverter converter

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Pros and cons of the device

The inverter type motor is compact and highly reliable. Other advantages include:

• Lack of rubbing elements.
• Increased efficiency and economy.
• Low noise level.
• Almost instantaneous achievement of the required speed.
• The ability to accurately maintain a given speed.

Despite the many advantages, the engine has disadvantages. The most significant of them are:

• The high price of the converter.
• The need for expensive repairs in the event of a breakdown.
• The need to maintain a certain voltage level in the network.
• Impossibility of functioning due to changes in the supply voltage of the network.

Using the motor in a washing machine

Inverter motor developed in 2005 engineers of the Korean concern LG, brought the production of washing machines to a new level. In comparison with its predecessors, the new motor has better specifications, greater wear resistance, lasts longer. Therefore, inverter motors are gaining more and more popularity and their production is growing. But is everything so rosy?

Advantages and disadvantages of the washing process:

1. Silence. Direct-drive technology is quieter than inverter-driven machines. The machine with the "inverter" makes sounds that resemble a squeak and howl. But the main reason for this is the turned on pump and the drum rotating in spin mode.
2. Saving. Electricity is mainly consumed not by the motor, but by the heating element. It turns out that you can save, but only 2-5% of energy.
3. Durability. This indicator achieved due to the lack of brushes, since bearings are also in equipment with an inverter motor. However, the bearings serve for about 10 years, and it costs 2-3 cu to replace them.
4. The engine can last more than 15 years.
5. Intensive spin. Spinning at high speeds makes the laundry almost dry, but the fabric is damaged and tears faster.
6. RPM accuracy. The main thing is the quality of washing, few people are interested in what revolutions are made.

It is recommended to pay attention to the functionality of the equipment. An inverter motor alone does not guarantee a perfect wash. If you are going to buy a washing machine with an inverter motor, purchase equipment exclusively at proven points. Most often cheap models - this is a banal fake, and it is unlikely that their characteristics will correspond to those declared by the manufacturer.