Air conditioner fan motor (electric motor): types and causes of malfunctions

The type of air conditioner motor affects the power and volume of the unit, as well as energy consumption. There are several types of motors: brushed, asynchronous and inverter. Knowing their pros and cons, it will be easier for the consumer to make a choice.

Collector type of engine

The collector motor of the air conditioner has a large starting torque without special modifications. It is easy to set up, for which it has been popular with home appliance manufacturers in the past.

With the development of technology, the collector motor has become less in demand for several reasons:

  • The maximum productivity is 40 thousand rpm. This is not enough for an air conditioner. For example, this number of revolutions is comparable to the operation of a centrifugal juicer.
  • Brush motors do not tolerate an aggressive environment, which quickly leads to a breakdown in urban operating conditions.
  • One of the biggest drawbacks is the noise during the operation of the air conditioner. It is impossible to calmly talk, read and generally rest next to him. Moreover, the noise level of such devices sometimes exceeds the silence law, which can result in an administrative fine.
  • With frequent work, you have to constantly clean the brushes.
  • Graphite, used as one of the materials, breaks down constantly.

Asynchronous motor type

By itself, an asynchronous motor has poor starting characteristics, which requires a large amount of electricity to start it fully. Application in air conditioners is irrational.

The designers tried to solve the problem. However, the increased power of the induction motor required increased cooling, which again led to high energy costs. The control characteristic was worsened by an increase in the active resistance of the rotor.

Inverter motor type

Depending on the heat load in the room, the rotational speed of the compressor motor is automatically adjusted. It goes into forced mode until the temperature set by the user is reached.

Having reached the set values, the air conditioner fan motor decreases the speed, while maintaining the desired temperature. This saves energy since the compressor does not cycle on and off.

Air conditioners that work by turning on the compressor to reach the desired temperature and then turning it off wear out faster. This is due to the fact that during the first seconds, the device runs without lubrication, since the oil from the compressor flows into the crankcase.

Principle of operation

Using a power electronics box allows the inverter motor to perform two sequential actions.

First, a direct current is generated by the mains alternating voltage. Then an alternating current of the required frequency is formed from the resulting constant voltage.

The power inverter unit, like any other converter, has less than 100% efficiency. With a long continuous operation at maximum speed, an air conditioner with an inverter motor type will lose about 10-15% of its efficiency compared to other types of devices.

The inverter air conditioner, after reaching the specified temperature, operates in a reduced compressor power mode, while other types of motors use a cyclic mode.

A non-inverter air conditioner, during the start of operation, experiences maximum load during transient processes: both electromechanical and thermodynamic.

The rotor requires full return from all mechanisms, while they need to pump up to 50% of freon to the high pressure zone from the low pressure zone. During all these processes, the cold has not yet begun to be produced.

Having reached the required values, the system equalizes the pressure in the upper and lower zones through a throttling device.

Freon boiling can occur in those parts of the air conditioner where it is not required: receiver, capillary tube, main line. This is because the starting pressure is too high.

The cold is used for some time not for its intended purpose: the compression compartment, the external unit, etc. is being cooled. As a result, performance is reduced.

Why choose an inverter air conditioner

The positive and negative sides of the inverter air conditioner should be highlighted.

Pros:

  • longer service life compared to other types of motors: 8-12 years versus 6-9 years;
  • with the correct setting of the air conditioner capacity, significant energy savings are possible without compromising comfort;
  • due to operation at low speeds both on the indoor and outdoor units, the noise level is significantly reduced compared to other types of air conditioners;
  • the compressor motor rotation speed is smooth, making it easier for the device to maintain the set temperature with minimal deviations;
  • quick installation of the preset mode: other models need about half an hour to start maintaining the set temperature; inverter motors shorten this process to 15 minutes.

There are many positive aspects of the inverter motor of the indoor unit of the air conditioner, but there are also disadvantages that should be taken into account:

  • long-term repair in case of breakdown due to the frequent lack of parts on the market; sometimes the waiting for the right part is delayed for several months;
  • during long-term operation without shutdown, increased power consumption begins;
  • due to the complexity of the electronic devices used in the engine filling, it is sensitive to sudden voltage surges and can fail because of them;
  • air conditioners with inverter motor type are more expensive than other systems for cooling and heating air.

Causes of malfunctions

Air conditioner repairmen identify several possible options that cause problems:

  • If the motor shaft is loose or if there is abnormal noise, the bearings must be replaced.
  • If the motor stops rotating, you will need to change the starting capacitors.
  • In the case when the air conditioner fan motor stops a few seconds after starting, the Hall sensor is faulty. This electronic module is responsible for the emergency shutdown of the engine in the event of a malfunction, preventing damage to it.

It is not worthwhile to take up work on your own if you do not have special knowledge. You should entrust the matter to the master.

Air conditioner fan motor selection

PG motor

In a split system, the engine is located in both the outdoor and indoor units. The fan motor of the outdoor unit of the air conditioner is made of metal, and the internal one is made of durable plastic.

Engine types:

  • Multi-winding: different fan speeds are obtained by supplying energy to different windings.
  • DC-inverter - most often used in inverter motors. By changing the amplitude of the constant voltage, the rotation speed is regulated.
  • PG-motor - with the help of a regulating element (triac or thyristor), voltage is applied through the winding, which consists of two parts. Different fan speeds are achieved by varying the amplitude of the control voltage.

Armed with knowledge, the user can easily select the engine for the air conditioner and detect problems in the system in time.

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Add a comment

  1. Alexander

    Thank you for the article. And now, I will write to you, due to the fact that I became the owner of an inverter condenser!
    In general, the old types of compressors serve reliably, but there are nuances, but not the essence. The service life of old split systems is much higher! If something is covered in it, it doesn't matter, you can change it yourself! And in the inverter, you can forget that you yourself will fix something, even calling the master will not help, since the master himself cannot fix it, but can make a stupid diagnosis and order the necessary part! The inverter itself is very expensive to repair. Despite the declared increased service life, they fail more often than a conventional split! Such units are not worth their money, especially with such inflated prices for them. They work noisily almost as well at maximum (when everyone climbs here and there without closing the door behind them)! Yes, the compressor itself is not so audible, the fans should not be muffled!
    So, before you take it, you should think, but why? If the main function is to cool, let the neighbors go deaf at least :)!

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