Electric motor or internal combustion engine? Pros and cons of the two technologies. Types of electric motors and their features Advantages and disadvantages of asynchronous motors

The article discusses various types of electric motors, their advantages and disadvantages, and development prospects.

Types of electric motors

Electric motors are currently an indispensable component of any production. They are also used very often in public utilities and in everyday life. For example, these are fans, air conditioners, heating pumps, etc. Therefore, a modern electrician needs to have a good understanding of the types and design of these units.

So, we list the most common types of electric motors:

1. DC electric motors, with a permanent magnet armature;

2. DC electric motors, with an armature having an excitation winding;

3. AC synchronous motors;

4. AC asynchronous motors;

5. Servomotors;

6. Linear asynchronous motors;

7. Motor rollers, i.e. rollers containing electric motors with gearboxes;

8. Valve electric motors.

DC motors

This type of motor was previously used very widely, but now it is almost completely replaced by asynchronous electric motors, due to the comparative cheapness of using the latter. A new direction in the development of DC motors is DC motors with permanent magnet armatures.

Synchronous motors

Synchronous electric motors are often used for various types of drive operating at a constant speed, i.e. for fans, compressors, pumps, DC generators, etc. These are motors with a power of 20 - 10000 kW, for rotation speeds of 125 - 1000 rpm.

Motors differ from generators structurally in the presence on the rotor, necessary for asynchronous starting, of an additional short-circuited winding, as well as a relatively smaller gap between the stator and the rotor.

Synchronous motors have efficiency higher, and the mass per unit of power is less than that of asynchronous ones at the same rotation speed. A valuable feature of a synchronous motor compared to an asynchronous one is the ability to regulate it, i.e. cosφ due to changes in the excitation current of the armature winding. Thus, it is possible to make cosφ close to unity in all operating ranges and, thereby, increase efficiency and reduce losses in the power grid.

Asynchronous motors

Currently, this is the most commonly used type of engine. An induction motor is an alternating current motor whose rotor speed is lower than the speed of the magnetic field created by the stator.

By changing the frequency and duty cycle of the voltage supplied to the stator, you can change the rotation speed and torque on the motor shaft. The most commonly used are asynchronous motors with squirrel-cage rotor. The rotor is made of aluminum, which reduces its weight and cost.

The main advantages of such engines are their low price and light weight. Repairing electric motors of this type is relatively simple and cheap.

The main disadvantages are the low starting torque on the shaft and the high starting current, 3-5 times higher than the operating current. Another big disadvantage of an asynchronous motor is its low efficiency at partial loads. For example, at a load of 30% of the rated load, efficiency can drop from 90% to 40-60%!

The main way to combat the shortcomings of an asynchronous motor is to use a frequency drive. converts 220/380V network voltage into pulsed voltage of variable frequency and duty cycle. Thus, it is possible to vary the speed and torque on the engine shaft within a wide range and get rid of almost all of its inherent defects. The only “fly in the ointment” in this “barrel of honey” is the high price of the frequency drive, but in practice all costs are recouped within a year!

Servo motors

These motors occupy a special niche, they are used where precision changes in position and speed are required. These are space technology, robotics, CNC machines, etc.

Such engines are distinguished by the use of small-diameter anchors, because small diameter means low weight. Due to the low weight, it is possible to achieve maximum acceleration, i.e. fast movements. These motors usually have a system of feedback sensors, which makes it possible to increase the accuracy of movement and implement complex algorithms for movement and interaction of various systems.

Linear asynchronous motors

A linear induction motor creates a magnetic field that moves a plate in the motor. The movement accuracy can be 0.03 mm per meter of movement, which is three times less than the thickness of a human hair! Typically a plate (slider) is attached to a mechanism that must move.

Such motors have a very high travel speed (up to 5 m/s), and therefore high performance. The movement speed and pitch can be changed. Since the engine has a minimum of moving parts, it has high reliability.

Motor rollers

The design of such rollers is quite simple: inside the drive roller there is a miniature DC electric motor and gearbox. Motor rollers are used on various conveyors and sorting lines.

The advantages of motor rollers are low noise level, higher efficiency compared to an external drive, the motor roller practically does not require maintenance, since it only works when the conveyor needs to be moved, its resource is very long. When such a roller fails, it can be replaced with another in a minimum amount of time.

Valve motors

A valve motor is called any motor in which the operating modes are controlled using semiconductor (valve) converters. As a rule, this is a synchronous motor with permanent magnet excitation. The motor stator is controlled by a microprocessor controlled inverter. The engine is equipped with a sensor system to provide feedback on position, speed and acceleration.

The main advantages of valve motors are:

1. Non-contact and absence of components requiring maintenance,

2. High resource;

3. Large starting torque and high torque overload capacity (5 times or more);

4. High performance during transient processes;

5. A huge range of speed adjustments of 1:10000 or more, which is at least two orders of magnitude higher than that of asynchronous motors;

6. The best indicators in terms of efficiency and cosφ, their efficiency at all loads exceeds 90%. While for asynchronous motors the efficiency at half loads can drop to 40-60%!

7. Minimum no-load currents and starting currents;

8. Minimum weight and dimensions;

9. Minimum payback period.

According to their design features, such motors are divided into two main types: contactless DC and AC motors.

The main direction of improving switched-type electric motors at the moment is the development of adaptive sensorless control algorithms. This will reduce the cost and increase the reliability of such drives.

In such a small article, of course, it is impossible to reflect all aspects of the development of electric drive systems, because This is a very interesting and fast-growing area in technology. Annual electrical exhibitions clearly demonstrate the constant growth in the number of companies seeking to master this area. The leaders of this market are, as always, Siemens AG, General Electric, Bosch Rexroth AG, Ansaldo, Fanuc, etc.

As many experts note, an electric car today is not just an alternative, but is already a direct competitor to the conventional internal combustion engine.

Of course, we are not talking about mass displacement yet, but experts believe that this is just a matter of time. The fact is that against the backdrop of the global environmental and fuel crisis, electric vehicles have every chance to push piston engines into the background.

Moreover, judging by the number of projects and the volume of funds invested in the development of electric cars, then the conclusion inevitably arises that the automakers themselves predict a great future for electric vehicles.

In this article we will look at the design and general principle of operation of electric vehicles, their features, advantages and disadvantages. We will also try to figure out which option is preferable, an electric car or a hybrid, what is better to choose in this or that case, etc.

Read in this article

Electric cars: features of electric cars

Let's start with the fact that until recently, Toyota and other brands were actually one of the most preferred, sought-after and widespread options around the world. You don’t have to look far for examples, since it’s enough to recall the premium model Lexus RX450h F Sport or the more modest and affordable Toyota Prius, etc.

Moreover, even today the current situation has not changed much, although recently a large number of competitors have appeared on the market who are able to offer consumers various versions of so-called “green” cars.

The fact is that, for all their advantages, cars with hybrid engines still represent an inextricable symbiosis of an electric motor and an internal combustion engine. This means that we are talking more about saving fuel, while “zero” emissions into the atmosphere and a complete rejection of petroleum products when using such machines still cannot be achieved.

The piston engine, which cannot be excluded from the general scheme of the hybrid, continues to require fuel, its lubrication system requires motor oil, etc. For this reason, the hybrid power plant can rather be considered the next round of evolution of the internal combustion engine, but not a full-fledged alternative option.

Taking into account the foregoing, it becomes clear that today only a fully electric car can offer a rejection of the internal combustion engine. By the way, the idea is far from new, since the first cars with an electric motor appeared even before vehicles with an internal combustion engine.

However, at the initial stage, the creators of electric cars faced a lot of problems (short range, high weight, difficulty in charging batteries, etc.), as a result of which this option could not withstand the competition, and gasoline and diesel engines quickly and permanently replaced electric cars.

Everything has changed relatively recently, in particular thanks to the development of modern technologies and the creation of the necessary devices for the accumulation and storage of electricity. In simple terms, we are talking about energy-intensive batteries for electric vehicles, as well as solutions for their fast recharging.

As a result, the electric car has recently become a publicly available production product. Such cars these days are produced by Japanese, European, American, and Chinese manufacturers. It is worth highlighting the popular electric car Nissan Leaf, the well-known Tesla Model S and Roadster, as well as Toyota RAV4EV, BMW Active C, etc.

Electrical machine diagram

Let's start with the fact that the design involves much fewer moving parts compared to an internal combustion engine. In other words, an electric car is simpler, and simplicity always means increased reliability.

The main structural elements are:

battery
electric motor;
simplified transmission;
special charger on board;
inverter and DC-DC converter;
developed electronic control system;

The battery in electric cars is needed to power the electric motor. The specified traction battery today is lithium-ion and consists of modules (cans) that are connected in series to each other. When it comes to capacity, there are different options available on different models. As a rule, the battery is selected for the car based on the power of the electric motor.

The traction motor creates torque on the wheels of the car and is a three-phase synchronous or asynchronous AC motor (asynchronous), producing, on average, from 20 to 150 kW or more. Note that an electric motor is much higher than an internal combustion engine, especially a gasoline one. In other words, the loss of useful energy in an internal combustion engine can reach up to 70%, while only 10% is lost in an electric motor.

As already mentioned, an electric car is driven by electric motors, of which there may be several. The electric motor is usually powered by a battery, but it is also possible to use solar panels, etc. However, in practice, serial electric cars are often equipped only with a battery.

Such a battery needs charging, which can occur either from an external source or while the electric car is moving. In the second case, we are talking about the recovery of braking energy.

So, the main advantages of an electric motor can be considered the available maximum torque at any speed; such a motor can spin the wheels back and forth without the need to install additional solutions. They also highlight the absence of the need to cool such a motor, the electric motor is capable of performing the functions of a generator, etc.

As a rule, electric cars today have several electric motors installed at once (for each wheel). As a result, traction is significantly improved compared to a scheme that involves equipping it with one electric motor.

There are also solutions where the electric motor is actually installed in the wheel. On the one hand, the transmission in this case is simplified as much as possible, but the amount of unsprung mass increases and the overall controllability of the car suffers.

By the way, the transmission of electric cars itself is initially simple and often consists of a single-stage gear reducer. As for the charger, the solution is located on the car itself and makes it possible to charge the battery from a regular electrical outlet. There is also a separate “output” for fast battery charging at special stations.

The inverter is used to convert DC current from the battery into three-phase AC voltage. This is the current needed to power the electric motor.

We also note that the design of electric vehicles also includes a similarity to the 12-volt power supply that is well known to motorists. In this case, the DC converter is responsible for charging such an additional battery, and the battery itself is needed to power various on-board devices and systems (electric power steering, dimensions and headlights, air conditioning, heated windows and seats, audio system with acoustics, etc.) .

The electronic system that plays a role in an electric car has a whole range of functions. The system is responsible for active safety, controls the operation of electric motors, monitors the state of the traction battery and charge level, determines energy consumption and activates energy saving modes when driving, etc.

If we talk about the device, there is a control unit (similarly) and a large number of sensors, as well as various actuators. Sensors record the speed of the car, the degree of load on the electric motors, as well as the position of the gas brake pedal and a number of other parameters.

Signals from the sensors enter the controller, after which the unit strives to create the best conditions for a particular mode while the electric vehicle is moving. Also on the instrument panel, the driver can see information about driving speed, charge consumption, residual charge, how many kilometers can still be driven, etc.

Types of electric vehicles and practical operation: pros and cons of electric cars

Global automakers in this area today are following two paths:

completely new models of electric cars are being created;
there is a transformation of cars already in the manufacturer’s line into electric cars;

Electric vehicles can also be divided into several types. As in the case of internal combustion engines, cars have long been divided into urban small cars, sports cars, etc. The situation is similar with electric cars.

There are electric cars that are positioned as solutions exclusively for the city. The maximum speed of such vehicles is relatively low (just over 100 km/h), as well as a relatively small range (70-80 km) in medium and high load modes.
The “universal” option should also be highlighted. Such electric cars are capable of accelerating to 140-160 km/h, and autonomy is also increased. This allows you to travel on the highway.
As for sports versions, such electric cars have a “maximum speed” of about 200 km/h and above. The acceleration dynamics are also very impressive. For example, today Tesla electric cars are capable of reaching “hundred” in less than 3 seconds, and the maximum speed of the fastest electric car in the world, which was built on the basis of the Chevrolet Corvette by the American company Genovation, during tests in 2017 exceeded 300 km/h .

It would seem that such cars are very close to cars with internal combustion engines in a number of important indicators. At first glance, electric vehicles have sufficient autonomy and acceptable acceleration dynamics. You can also highlight the ease of operation, low maintenance and service costs, which should certainly persuade reasonable consumers to choose an electric car. However, in practice everything looks a little different.

Let us immediately note that it is precisely the operating features and a number of other factors that still do not allow electric cars to become a mass solution. First of all, the cost of such vehicles continues to remain quite high compared to competitors with gasoline or diesel internal combustion engines.

Moreover, the efficiency of modern diesel engines allows these units to seriously compete not only with gasoline cars, but also with electric vehicles. It should also be emphasized that it takes a long time for an electric car battery to charge from a household outlet, and fast charging stations are not often found due to the poor development of infrastructure. This is especially true for the CIS countries.

As for autonomy, the data declared by the manufacturer often does not entirely correspond to reality. First, in practice, especially in the cold season, the battery discharges faster.

Secondly, if the driver practices dynamic driving, then a full battery charge may not last for 70-80 km. around the city, but only 40-50. To confirm this information, it is enough to read the real reviews of Nissan Leaf owners, since this budget version of the electric car is one of the most affordable and most common today.

In simple words, the range of an electric vehicle without recharging is not constant, but depends on numerous factors, ranging from the condition and capacity of the battery to driving style. If we add to this the use of air conditioning, dimensions, heating and other solutions, then on a single charge, even under ideal road conditions, the mileage will inevitably be reduced by 20-30% or more.

If your driving style is active (constantly exceeds the average speed of 60 km/h), then you can count on the full 50%. It turns out that if the manufacturer promises 140-160 km on a single charge, then this figure assumes driving at a speed of no more than 70 km/h, and then only on condition that the battery is in full working order (without loss of battery capacity).

However, if you accelerate an electric car, for example, to 130 km/h on the highway, then the range without recharging will be only 70 km. As you can see, while this is still acceptable for the city, using an electric car for country trips is very difficult.

Now a few words about the battery. The battery that is commonly used today is lithium-ion. Its production requires large expenses, which greatly affects the overall cost of electric cars. However, the service life of such batteries is limited to an average of about 5 years.

This means that although the basic cost of maintaining an electric car is several times lower than its analogues with an internal combustion engine, the higher initial cost and the need to replace an expensive battery (on average after 5 years) put the economic advantages and feasibility of purchasing such a car in great doubt. It is also worth adding to this the constant rise in electricity prices, which also affects the cost of owning an electric car.

What's the result?

Taking into account the above, it becomes clear that the active implementation of innovative technologies has made it possible to significantly increase the autonomy of a modern electric vehicle. However, the use of such technologies greatly affects the final cost of the vehicle, preventing it from becoming a mass solution.

As for the more affordable versions, batteries, charging time from a household network of about 7-8 hours, as well as a small power reserve continue to be the weak points of such electric vehicles.

It should also be noted that not all countries are actively developing infrastructure in the form of creating special stations for fast charging or replacing batteries. The situation is also the same with specialized services for the repair and maintenance of electric vehicles. While in Europe and the USA much attention is paid to this issue, in the CIS, unfortunately, it is still impossible to talk about creating acceptable conditions for the normal operation of electric cars.

It is quite possible that the situation will change soon, but today an electric car on domestic roads continues to be a rarity. Usually such a car can be found in large cities. At the same time, wealthy owners often purchase electric cars more for entertainment than for practical purposes.

In other words, for the vast majority of drivers it is not worth considering an electric car as their main and permanent means of transport, especially when talking about countries in the CIS.

1. History of the use of electric motors in car design

An electric motor is an electrical converter capable of transforming electricity into its mechanical version. A side effect of this action is the release of a certain amount of heat.

This device is used as a power plant in “eco-friendly” cars: electric cars, hybrids and cars powered by fuel cells. But if you don’t take into account the “heart” of the vehicle, low-power electric motors can be found even in the simplest gasoline sedan (for example, they are equipped with an electric door drive). The concept of electric transport, in general terms, appeared back in 1831, immediately after Michael Faraday discovered the law of electromagnetic induction. The first engine, the operating principle of which was based on this discovery, was a unit developed in 1834 by the Russian physicist-inventor Boris Jacobi.

For the first time, vehicles equipped with electric motors used as a vehicle's power plant appeared in the 1880s and immediately gained universal popularity. This phenomenon can be explained quite simply: at the turn of the 19th and 20th centuries, internal combustion engines had a bunch of shortcomings that showed the new product in a very favorable light, since its characteristics were significantly superior to internal combustion engines. However, not much time passed and, thanks to the increase in power of gasoline and diesel engines, electric motors were forgotten for many decades. The next wave of interest in them returned only in the 70s of the twentieth century, during the era of the Great Oil Crisis, but again it did not reach mass production.

The first decade of the 21st century is the real Renaissance for electric motors in hybrid and electric vehicles. This was facilitated by several factors: on the one hand, the rapid development of computer technology and electronics made it possible to control and save battery power, and on the other hand, gradually increasing prices for oil fuel forced consumers to look for new, alternative sources of energy.

All in all, The entire history of the development of electric motors can be divided into three periods:

First (initial) period, covers 1821-1834 of the 19th century. It was at this time that the first physical instruments began to appear, with the help of which the continuous conversion of electrical energy into mechanical energy was demonstrated. Research by M. Faraday in 1821, which was carried out to study the interaction of conductors with current and a magnet, showed that an electric current can cause rotation of a conductor around a magnet or, conversely, a magnet around a conductor. The results of Faraday's experiments confirmed the real possibility of building an electric motor, and many researchers, even then, proposed various designs.

Second phase The development of electric motors began in 1834 and ended in 1860. It was characterized by the invention of designs with a rotating motion of a salient pole armature, but the shaft of such motors, as a rule, was sharply pulsating. The year 1834 was marked by the creation of the world's first electric DC motor, the creator of which (B.S. Jacobi) implemented in it the principle of direct rotation of the moving part of the power unit. In 1838, tests of this engine were carried out, for which it was installed on a boat and set free to sail along the Neva. Thus, Jacobi's development received its first practical application.

Third stage in the development of electric motors, it is generally accepted that the time period is from 1860 to 1887, which is associated with the development of a design with an annular non-salient pole armature and an almost constantly rotating torque. During this period, it is worth noting the invention of the Italian scientist A. Pacinotti, who developed the design of an electric motor consisting of a ring-shaped armature that rotated in the magnetic field of electric magnets. The current was supplied using rollers, and the electromagnetic winding was connected in series with the armature winding. In other words: the electric machine was excited sequentially. A distinctive feature of Pacinotti’s electric motor was the replacement of the salient-pole armature with a non-salient-pole one.

2. Types of electric motors

If we talk about modern electric motors, they have a fairly wide variety of types, and the most famous of them include:

- AC and DC motors;

Single-phase and multi-phase motors;

Stepper;

Valve and universal commutator motor.

DC and AC motors, as well as universal motors, are part of widely known magnetoelectric power units. Let's take a look at each type in more detail.

DC motors are electric motors that require a DC source to power them. In turn, based on the presence of a brush-commutator unit, this type is divided into brushed and brushless motors. Also, thanks to the named unit, the electrical connection of the circuits of the stationary and rotating parts of the unit is ensured, which makes it the most vulnerable and difficult to maintain element.

For the type of arousal, all collector types are again divided into subspecies:

- power plants with independent excitation (comes from permanent magnets and electromagnets);

Self-excited motors (divided into parallel, series and mixed excitation motors).

The brushless type of electric motors (they are also called “valve motors”) are devices presented in the form of a closed system that uses a rotor position sensor, a control system, and an inverter (power semiconductor converter). The operating principle of these motors is the same as that of representatives of the synchronous group.

An AC motor, as the name suggests, uses alternating current power. Based on the principle of operation, such devices are divided into synchronous and asynchronous motors. In synchronous motors, the rotor rotates along with the magnetic field of the incoming voltage, which allows these motors to be used at high power. There are two types of synchronous motors - stepper and switched reluctance motors.

Asynchronous electric motors, like the previous version, are representatives of alternating current electric motors, in which the rotor speed is slightly different from the similar frequency of the rotating magnetic field. Today, it is this type that is most often found in use. Also, all AC motors are divided into subtypes depending on the number of phases. Highlight:

- single-phase (manually started or equipped with a starting winding, or have a phase-shifting circuit);

Two-phase (including capacitor);

Three-phase;

Multiphase.

Universal type commutator motor- This is a device that can operate on both direct and alternating current. Such motors are equipped only with a series excitation winding with a power of up to 200 W. The stator has a laminated design and is made of special electrical steel. The excitation winding has two operating modes: with alternating current it is partially turned on, and with constant current it is fully turned on. Typically, such devices are used in power tools or some other household appliances.

An electronic analogue of a brushed DC motor is a synchronous motor that has a rotor position sensor and an inverter. Simply put, a universal brushed motor is a DC electric motor, the field windings of which are connected in series, ideally optimized for operation on alternating current. Regardless of the polarity of the incoming voltage, this type of power plant rotates in one direction, because due to the series connection of the rotor and stator windings, the poles of their magnetic fields change simultaneously, which means that the resulting torque continues to be directed in one direction.

To ensure operation on alternating current, a stator made of soft magnetic material with low hysteresis (resistance to the magnetization reversal process) is used, and to reduce losses due to eddy flows, the stator design is made of insulated plates. Dignity The operation of an AC electric motor is that at low speeds (starting, restarting), the current consumption, and, accordingly, the maximum motor torque is limited by the inductive reactance of the stator windings.

In order to bring the mechanical characteristics of general-purpose motors closer together, sectioning the stator windings is often used, that is, separate terminals are created for connecting alternating current and the number of winding turns is reduced.

The operating principle of a reciprocating synchronous electric motor is based on the fact that the moving part of the motor is presented in the form of permanent magnets, which are attached to a rod. An alternating current passes through the stationary windings, and permanent magnets, influenced by the magnetic field, move the rod in a reciprocating manner.

Another classification, which allows us to distinguish several types of electric motors, is based on the degree of environmental protection. Based on this parameter, electrical power plants can be protected, closed and explosion-proof.

Protected versions are closed with special flaps that protect the mechanism from the ingress of various foreign objects. They are used where there is no high humidity and no special air composition (free from dust, smoke, gases and chemicals). Closed types are placed in a special shell that prevents the entry of gases, dust, moisture and other elements that can harm the motor mechanism. These devices can be sealed or non-sealed.

Explosion-proof mechanisms. They are installed in a housing that, in the event of a motor explosion, will be able to protect the remaining parts of the device from damage, thereby preventing the occurrence of a fire.

When choosing an electric motor, pay attention to the operating environment of the mechanism. If, for example, the air does not contain any foreign impurities that could harm it, then instead of a heavy and expensive closed engine it is better to purchase a protected one. A separate point is also worth remembering about the built-in electric motor, which does not have its own shell and is part of the design of the working mechanism.

3. Advantages and disadvantages of electric motors

Like any other device, an electric motor is not “sinless”, which means that, along with undeniable advantages, it also has certain disadvantages. Let's start with the positive aspects of use, which include:

1. No friction losses during transmission;

2. The efficiency of a traction electric motor reaches 90-95%, while that of an internal combustion engine is only 22-60%;

3. The maximum torque value of the traction motor (traction motor) is achieved already from the beginning of movement, at the moment the engine starts, therefore, a gearbox is simply not needed here.

4. The cost of operation and maintenance is comparatively lower than that of an internal combustion engine;

5. No toxic exhaust gases;

6. High level of environmental friendliness (petroleum fuels, antifreezes and motor oils are not used);

7. Minimum possibility of explosion in case of accident;

8. Simple design and control, high level of reliability and durability of the undercarriage;

9. Possibility of recharging from a regular household outlet;

10. Reduced noise with fewer moving parts and mechanical gears;

11. Increased smoothness of operation with a wide frequency range of changes in the rotation of the motor shaft;

12. Possibility of recharging during regenerative braking;

13. Possibility of using the electric motor itself as a brake (electromagnetic brake function). There are no mechanical options, which helps to avoid friction and, consequently, brake wear.

Considering the above, we can come to the logical conclusion that a car equipped with an electric motor is approximately 3-4 times more efficient than its gasoline counterparts. However, as we have already said, there are still disadvantages:

- the operating time of the engine is limited by the maximum possible volume of batteries, that is, compared to internal combustion engines, they have a much shorter mileage per fill-up;

Higher cost, but there is a chance that with the start of mass mass production the price will decrease;

The need to use additional accessories (for example, fairly heavy batteries weighing from 15 to 30 kilograms and special chargers that are intended for deep discharge).

As you can see, there are not so many main shortcomings, and over time their number will continue to fall rapidly, because automotive engineers and designers will “work on the mistakes” with each subsequent product release.

4. Identifying and troubleshooting motor problems

Unfortunately, for all its positive aspects, the electric motor, like any other device, is not protected from breakdowns and periodically fails. The most common malfunctions of electric motors include:

When starting the engine it makes a loud noise.Possible reasons such a phenomenon may be a decrease or complete absence of voltage in the supply network; incorrect location of the beginning and end of the stator winding phase; motor overload or malfunction in the drive mechanism. Naturally, to eliminate the problems that have arisen, you need to either find and eliminate the malfunction, or reconnect, but according to the correct circuit, or reduce the load or eliminate the malfunction in the drive mechanism.

The running engine suddenly stops. Possible reasons: the voltage supply has stopped; there were malfunctions in the operation of switchgear equipment and the power supply network; the motor or drive mechanism is jammed; the protection system worked. To eliminate breakdowns you should: find and repair a break in the circuit; eliminate malfunctions in the equipment of the switchgear and power supply network; repair the drive mechanism; carry out stator diagnostics and, if necessary, carry out repair measures.

The shaft rotates, but cannot reach normal speed. Possible reasons: during the acceleration of the car, one of the phases turned off; the network voltage has decreased; the engine is under excessive load. Raising the voltage will help eliminate any malfunctions; connecting the disconnected phase and eliminating motor overload.

The electric motor is overheating. Possible reasons: there is an overcurrent; the voltage in the network has decreased or increased; the ambient temperature has increased; normal ventilation is disrupted (ventilation ducts are clogged); The normal operation of the drive mechanism has been disrupted.

Ways to solve the problem: ensure a normal load level; set the optimal permissible temperature; clean the ventilation ducts; repair the drive mechanism.

The motor makes a loud noise and does not reach normal speed.Possible reasons: an interturn short circuit has occurred in the stator winding; grounding the winding of one phase in two places at once; the appearance of a short circuit between phases; break of some phase. In this case, there is only one way out - you will have to change the stator.

Increased vibration of a running motor.Possible reasons: low foundation rigidity; errors in compatibility of the drive shaft with the motor shaft; The coupling or drive is not balanced enough. Way out of this situation: increase rigidity; balance and improve relevance.

Increased heating of bearings. Possible reasons: bearing damage; Incorrect alignment of the motor with the drive mechanism. Correct installation of the engine or replacement of the bearing will help solve the problems that have arisen.

Reduced winding insulation resistance. The causes of malfunctions in this case lie in contamination or dampness of the windings, and drying the parts will help eliminate them.

The main difference between an inverter motor and a conventional electric motor is that it does not have brushes. The units are used in refrigerators, automatic washing machines, and air conditioners. The converter, which acts as a power source for the motor, converts alternating voltage into direct voltage. Resulting DC Current converted to alternating current of a given frequency

The main parts are the motor itself and the frequency converter, which ensures the operating 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 output frequency in converters varies widely, and its maximum values can be tens of times higher than the frequency of the supply network.

In the inverter converter, double voltage conversion occurs. The sinusoidal voltage at the converter input is first rectified in the rectifier block, filtered and smoothed by electrical filter capacitors. Next, from the obtained constant voltage using control circuits and output electronic keys, a sequence of controlled pulses of the required shape and frequency is specified. Using pulses, an alternating voltage of the required magnitude and frequency is created, which is generated at the output of the converter.

The sinusoidal alternating current generated by the converter on the windings of the electric motor is formed as a pulse-frequency or pulse width modulation. Electronic switches for converters are, for example, switchable GTO thyristors, 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. The stator rotates a rotor with permanent magnets attached to it. The number of magnets is three times less than the number of field windings. There is no commutator-brush assembly in such an engine.

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

Pros and cons of the device

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

Despite a lot of advantages, the engine has disadvantages. The most significant of them include:

High price of the converter.
The need for expensive repairs in case of breakdown.
The need to maintain a certain voltage level in the network.
Impossibility of operation due to changes in the supply voltage.

Using the motor in a washing machine

The inverter motor, developed in 2005 by engineers of the Korean concern LG, brought the production of washing machines to a new level. Compared to its predecessors, the new engine 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:

It is recommended to pay attention to the functionality of the equipment. The inverter motor itself does not guarantee perfect washing. If you are planning to buy a washing machine with an inverter motor, purchase the equipment exclusively from trusted outlets. Most often, cheap models - this is a banal fake, and it is unlikely that their characteristics will correspond to those declared by the manufacturer.

Electrification, which began in the 20th century, led to the emergence of a huge number of useful inventions. One of them was an electric motor.

The motor lost mechanically rubbing and sparking components, surpassing many types of drives popular at that time. Today, there are various types of electric motors, which allows you to implement the best option in a particular machine. Which units are considered in demand, and what are their key features?

It is immediately worth noting that motors are roughly divided into two types: direct and alternating current. Therefore, we will consider the characteristic features of each of them.

DC devices

Such units make it possible to create adjustable electric drives with excellent performance properties. There are two categories of DC motors: brushed and valve-type.

The first are characterized by the presence of a brush-collector unit, which facilitates the electrical connection of the stationary and rotating parts of the unit. Brushless (valve) motors are electric motors with a closed system. They work the same way as synchronous ones. Such units can have any dimensions. The smallest ones are equipped with PCs, toys and other devices.

DC electric motors are used in various fields due to the huge number of positive aspects:

ease of control and speed adjustment;
good starting properties;
compactness;
Possibility of use in different modes.

However, collector devices require labor-intensive preventive maintenance. And the cost of producing the units is quite high, which is reflected in their price.

AC devices

These units are divided into synchronous and asynchronous. The key difference is that in the first electric motors, the 1st harmonic of the starter's magnetomotive force moves in a manner similar to the rotor speed. With asynchronous ones, the field rotates faster. And since AC motors are used especially often, they are worth considering in more detail.

Synchronous models

Many types of computer equipment are equipped with these engines. The advantages of using them are obvious:

constant rotation speed;
low sensitivity to voltage changes;
Possibility of use as a power generator.

Of course, there are some disadvantages in the form of difficulties with starting, complexity of the design and speed adjustment.

Asynchronous units

Here the rotor speed differs from the torque field indicators. Based on their design features, devices with phase-wound and squirrel-cage rotors are distinguished. There are practically no other differences in design. They only affect the number of windings, according to which the devices are divided into single-, two- and three-phase.

Today, asynchronous units are included in a huge number of electrical machines. Due to the variety of physical and technical characteristics of the device, you can choose the optimal one (depending on operating conditions).

For example, a three-phase electric motor 1.1 kW 3,000 rpm is suitable for equipping concrete mixers, compressors, pumps, etc. A single-phase unit is applicable in low-power devices, including small room fans.

Among the advantages of asynchronous electric motors it is worth highlighting:

ease of manufacture;
increased reliability;
low operating costs.

However, such devices depend on the mains voltage, have a small starting torque and cause difficulties in accurately adjusting the speed. This is important to consider when purchasing.

An Indispensable Invention

Electric motors are used literally everywhere. Without them it is impossible to imagine the operation of most machines. Their use helps reduce human labor costs and make everyday life as comfortable as possible.