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What is an electric motor?

Basically, the electric motor or electric motor is available in the types of ordinary electric motor (TEFC) or other types, i.e. explosion-proof electric motor, as well as cooling motor, and in terms of electricity consumption, it is presented in two types: single-phase electric motor and three-phase electric motor.

Types of electric motors

In today's advanced machine life, there is no person who does not encounter an electric motor or an electric motor or a dynamo. Although he may not realize it. In general, wherever there is movement, there is an electric motor.

DC motor
Series engine
Parallel motor
Compound engine
Self-propelled motor
Permanent magnet motor (PMDC)
AC motor
Induction motor
Synchronous motor
Special engines
stepper motor
Brushless DC motor
Hysteresis motor
Reluctance motor
Universal engine

Electric Motor

It is a type of machine that converts electrical energy into mechanical movement. The general idea is based on the fact that when a current-carrying conductor is under the effect of a magnetic field, a force is exerted on that current-carrying conductor by the magnetic field. Most electric motors are rotary. But there are also linear motors.

Every rotating electric motor consists of two moving and driving parts. The moving part of the rotor and the fixed part which is usually located inside the motor are also called the stator. In an electric motor, the rotor rotates around its axis due to the torque caused by the force created by the magnetic field in the stator. Each electric motor is powered by DC direct current or AC alternating current based on its structure.

Electro-Motor

Electric definitions and terms

current

The ratio of changes in electric charge (q) to time (t) is current and its unit is ampere (A) and it is measured by an ammeter device which is installed in series in the circuit.

potential difference

Potential difference or voltage is a quantity that causes current to flow in a closed circuit, and its unit is volts (V) and is measured by a voltmeter that is connected in parallel in a closed circuit.

nominal current

The current that an electrical device can pass through in specified conditions, without being overheated or subjected to excessive mechanical stress.

If a voltage equal to 1 volt is applied to two resistors and a current of 1 amp passes through it, the resistance value is 1 ohm. The unit of electrical resistance is Ohm (?).

Watt

The amount of energy produced is expressed in watts. For example, light bulbs are marked with wattage, which shows how much light energy this lamp can give.

amp

Ampere is the amount of electricity flowing in a circuit. In fact, when a force causes electrons to move in a specific direction, electric current is produced. Current (I) is expressed in ampere (A).

volt

Volts or voltages are measured values. In simpler terms, the force that moves free electrons is called electric voltage. The electric potential difference (R) in terms of volts (V) is an indicator of electricity. In fact, it is the electric potential difference between two points.

Magnetic field

The electric field at any point is defined as the force acting on the unit test charge q0. In other words, to determine the electric field E, we divide the force F by the charge q0.

Electric field

AC motors

Components of electric motors

First, let's take a look inside a simple electric motor. A simple engine consists of 6 parts:

Armature
Conductive coal
Switch for changing the direction of electricity
axis
magnet
DC power supply

Electric motors are divided into two main categories in terms of current consumption:

Electric motor or electric motor (Direct Current) or DC direct current
Electric motor or electric motor (Alternative Current) or AC alternating current

What are DC or direct current electric motors?

DC or direct current motor has an armature of electromagnets. A rotary switch called a commutator reverses the direction of the electric current twice in each cycle so that the electromagnets generated in the armature attract and repel the permanent magnet outside the armature. The rotation speed of the DC motor depends on the braking torque, in other words, it depends on the input voltage and input current torque.

DC electric motor

Series DC electric motor

Series DC motors have high starting torque and therefore are used in industries that require high starting torque, such as cranes, hydraulic lifts, impact presses, and elevators. Also, this type of dynamo is used in urban locomotives (metro and tram), which is called traction motor.

Shunt DC electric motor

Shunt or parallel DC motors have maximum torque at rated speed. For this reason, it is used in applications such as industrial ventilators and blowers. These types of motors should not be started under heavy load because their armature current is too high and the motor will be damaged.

Compound DC electric motor

In compound motors, there are features of series and shunt motors and they include two categories.

1. Additional compound DC electromotor

This type of motor is used in cases where the characteristics of a series motor are required, but when the load is removed, the motor cannot be controlled and its speed does not increase too much. Like lathe machines, which are unloaded and loaded again in every working cycle. In various industries, it is usually used instead of using an additional compound dynamo whose design is similar to series electric motors.

2. Defective compound DC electric motor

At loads less than nominal loads and in cases where almost constant speed is needed, compound motors are used. These motors are usually used in laboratories to provide constant speed.

Advantages of using AC electric motors

Simple and solid design
reasonable price
Low maintenance cost
Easy and complete connection to a power source

There are various types of AC or induction motors in the industry. Different electric motors are suitable for different tasks. Although the AC motor is easier to design than the DC electric motor. But controlling the speed and torque in different types of AC electric motors requires a deeper understanding of the design and specifications of these types of motors.

Stator

The stator is made of several thin pieces of aluminum or light iron. These parts are stapled together as a hollow cylinder. Coils of coated wire are embedded in these grooves. Each coil group with the core surrounding it forms a magnetic magnet (with two bridges) to operate with AC power. The number of poles of an AC motor depends on the internal connection of the stator coils. Stator coils are directly connected to the energy source. They are connected in such a way that a rotating magnetic field is produced by establishing AC power supply.

rotor

The rotor is made of several separate thin steel pieces with copper or aluminum rods inserted between them. In the most common type of rotor (squirrel cage rotor), these rods are electrically and mechanically connected by rings at their ends. Almost 90% of electric motors have a squirrel cage rotor and this is because this type of rotor has a strong and simple structure. This rotor consists of a multi-piece cylindrical core with an axis that has parallel slits for placing the conductors inside. Each slot includes a copper or aluminum or alloy rod. In these rods, a short circuit is permanently established by their end rings as seen in figure two. Because this type of assembly is just like a squirrel cage, this name was chosen for it. The rotor bars are not exactly parallel to the axis. Instead, they tend to be installed for two important reasons.

The motor is operated without sound by reducing the magnetic sound in order to reduce the harmonics in the gaps.
The tendency of the rotor to hang is reduced. The rotor teeth try to remain in front of the stator teeth due to direct (pure) magnetic attraction. This happens when the number of rotor and stator teeth are equal.

Types of AC electric motors

Synchronous AC electric motor
Asynchronous AC electric motor

Synchronous AC electric motor

In synchronous dynamo, rotor and stator are wound. When the stator is connected to the power source, a rotating field is created in the motor, which rotates at synchronous speed. The rotor is also coiled and fed by a DC source. By connecting the DC current to the rotor, the rotor starts to rotate with the stator field. To start the synchronous electric motor, first the electric motor rotates at synchronous speed after cutting off the primary driver.

Application of synchronous electric motor

This product is for correcting the power factor (Cos?), in this case, no load is placed on the axis of the synchronous motor, that is, the electric motor works without load. In this case, the synchronous motor is also called a synchronous capacitor and is used in factories.
These motors can be used both as a synchronous generator and as a synchronous electric motor.
Because the synchronous electric motor has a constant speed, it is used in equipment such as electric watches that require this feature.

Advantages of synchronous electric motor

It is not sensitive to voltage fluctuations.
It has a very high efficiency.
It has a suitable and adjustable power factor.
This electric motor can work directly with high voltage.

Disadvantages of synchronous electric motor

The speed of this electric motor is fixed and cannot be adjusted for higher or lower speeds.
This electric motor cannot bear extra load.
In addition to the alternating current for the stator winding, the permanent current is also required for the poles of this electric motor, thus increasing the price of this electric motor compared to its similar cases.
It needs an initial starting device that can be an auxiliary engine.

Asynchronous AC electric motor

What is an AC asynchronous electric motor of a squirrel cage?

The rotor of squirrel cage motors is cylindrical in shape, with aluminum or copper rods inside iron or steel peripheral grooves, which are made in two ways, the first type is made of round rods, and the second type is made of rectangular rods. Or it is formed in the form of two circles that are connected or separated from each other. The rotor bars of the electric motor are designed diagonally for the reason that under the effect of the stator fields on the rotor there is a kind of overlap and vibration or locking at the moment of starting is prevented.

Advantages of squirrel cage asynchronous electric motor

Due to its reasonable price and simplicity in design, it has replaced other engines in many industries.
The rotation speed of this dynamo is almost constant at different loads.
Changing the load does not cause this type to stop moving.
Compared to slip ring electric motors, they have a better power factor.

Disadvantages of squirrel cage asynchronous electric motor

When it is working with little work, its power factor is reduced.
It is impossible to change the circuit of this type with the voltage reduction method and it needs a device (AC Drive) for this.
Squirrel cage asynchronous electric motors are sensitive to voltage changes, and if the voltage decreases, the current increases accordingly.
It has low torque.
During the start of this motor, they take a lot of current from the grid, about 3 to 7 times the rated current.

Squirrel cage rotor

AC asynchronous electric motor, wire winding rotor

The problem of squirrel cage motors is the very low resistance of its rotor. The rotor bars are short-circuited by a ring at the beginning and end. This issue at the moment of starting, when the rotor is not magnetic, the flux (the electric field lines that pass through the surface perpendicular to the path are called electric flux) attracts a lot of it to become magnetized and causes the current of the electric motor to increase, as a result The starting moment takes a lot of current from the network and causes a decrease in the starting torque. In order to solve this problem, coiled rotor electric motors were designed and built, which solved this defect to a large extent.

In these coiled rotor products, instead of having a rod in the rotor, the rotor is coiled and the ends of these coils are connected to the sliding rings that are guided outside the motor by brushes. By placing resistance banks (starter) in the way of these coils, the resistance of the rotor can be increased or decreased and the motor current can be changed as desired.

The starter has three steps to bring the engine to the nominal speed. The first stage of the resistance bank is removed from the circuit by the corresponding contactor when the engine reaches ??% of the nominal speed and the dynamo continues to rotate. The next steps are called round in ??% and ??% rounds. After this cycle, the starter is completely removed from the circuit and the engine is directly connected to the network and reaches the nominal cycle.

Wire wound rotor electric motors are used in mills, stone crushers, cranes and in cement and steel industries.

The advantages of the AC asynchronous electric motor of the coiled rotor

The generated heat occurs outside the starter.
This dynamo has the ability to start consecutively and under load.
The starting current of the electric motor can be adjusted.
Winding rotor electric motors have maximum torque at the moment of starting.

AC electric motor

AC motors, like most electric motors, have an external fixed part called the stator and a rotor that rotates inside. Electric motors use the rotating magnetic field virtually to turn their rotor. The AC three-phase electric motor is the only type in which the rotating magnetic field is naturally produced by the stator due to its feeding nature. While in DC motors, they need an electrical or mechanical device to produce this rotating field. To start a single-phase AC electric motor, an external electrical device is needed to produce this rotating magnetic field. Inside each AC motor, two sets of magnetic magnets are installed.

Types of electric motors

Single phase electric motor
Three-phase electric motor

Electric motors are usually divided based on the number of stator coils.

Single phase electric motor

Due to the reasonable price and low maintenance cost, they have the highest consumption in the single-phase alternator industry. In this model of electric motors, a coil or coil is used and it works with a single-phase alternating power source. The single-phase motor is not self-starting, and in all types of single-phase electric motors, the rotor is of the squirrel cage type. When the motor is connected to a single-phase power source, the main coil has an alternating current. This alternating current produces a pulsating magnetic field. Due to induction, the rotor is stimulated. Because the main magnetic field is pulsating, the torque required for the rotation of the electric motor does not occur and causes the rotor to vibrate and not rotate. Therefore, the single-phase electric motor needs a starter device that can produce the initial kicks for the motor to rotate. A single-phase electric motor starter is basically an extra coil in the stator (starting screw). Coil start can have series capacitors or centrifugal switch.

When the supply voltage is established, the current in the main coil drops the supply voltage due to the resistance of the main coil (voltage turns into current). At the same time, the current in the starter coil changes to increase the supply voltage depending on the resistance of the starter device. The interaction between the magnetic fields that create the main coil and the starter device (including auxiliary coil and capacitor) creates a field that rotates in one direction. The axis of the electric motor starts to rotate in the direction of this field. When the engine to ?? The percentage of its allowed speed is reached. A switch that avoids the center of the starter coil takes it out of the circuit. From this moment on, the single-phase electric motor can maintain enough torque to continue its operation. Except for special types, usually all single-phase motors are only used for applications less than 3 horsepower. According to the types of starting techniques, single-phase AC electric motors are classified as follows.

Types of single-phase electric motors

Single-phase AC electric motor with broken phase
AC single phase electric motor with capacitor start
AC single-phase electric motor with split permanent capacitor

Single-phase AC electric motor with broken phase

These engines have two coils. In the starter coil of this dynamo, thinner wire and fewer turns are made than the main coil to create more resistance. This broken phase electric motor is also known as induction start/induction function. In the field, the start coil is placed at an angle other than that of the main coil, which causes the electric motor axis to start rotating. The main coil, which is made of thicker wire, keeps the electric motor always rotating. Good uses for broken phase electric motors include small sanding stones, blowers and small fans and other devices that require low starting torque and require electric motors with a power of ?/?? until the ?/? It is horse power. These electric motors are not suitable for applications that require continuous switching on and off or high torque.

Single phase electric motors

AC single phase electric motor with capacitor start

This type is the same motor with broken phase, modified with a capacitor in series with it to improve the start. Like the normal dynamo with broken phase, this type of motor has a centrifugal switch that when the axis of the electric motor to ?? When the percentage of nominal speed is reached, it takes the starter coil out of the circuit. Since the capacitor is in the starting circuit, it produces more starting torque, which is usually around ??? until the ??? The percentage of nominal torque and the starting current is usually between ??? until the ??? The percentage of nominal current is much lower than the motor with a broken phase and because of the thicker wire in the starter circuit. A modified type of electric motor with a capacitor start is an electric motor with a resistance start.

In this type of electric motor, the start capacitor is replaced by a resistor. The electric motor with resistance start is used in applications where the amount of starting torque is lower than the value produced by the electric motor with capacitor start. Regardless of the cost, this electric motor does not have major advantages over the electric motor with capacitor start. These motors are well used in various types of pulley and belt applications such as small conveyor belts and in pumps, large blowers and gear applications.

Single-phase AC electric motor with permanent split capacitor

This product has a type of capacitor permanently connected in series to the starter coil. This causes the starter coil to act as an auxiliary coil until the electric motor axis reaches its rated rotation speed. Since the main performance capacitor must be designed for continuous use, it cannot produce the equivalent starting power of a capacitor start electric motor. The starting torque of a single-phase electric motor with permanent capacitor is usually low and around ?? until the ??? It is the percentage of the nominal torque. Single-phase electric motors with permanent capacitors have a low starting current, which is usually less than ??? It is the nominal current percentage that makes them very suitable for high-speed on-off periods. Single phase electric motor has many advantages. The single-phase electric motor design can be easily modified for use with rotational speed controllers. They can also be designed for optimal efficiency and high power factor at rated load. They are considered as the most reliable single-phase electric motors. Especially because they don't need a centrifugal switch. Depending on their design, these motors have a wide variety of uses, which include use as fans, blowers with low starting torque, and non-permanent working periods such as garage door openers.

Single-phase AC electric motor with capacitor start/capacitor operation

This type, like the motor with capacitor start, has a starter type capacitor in series mode with an auxiliary coil for high starting torque. Also, like an electric motor with a permanent capacitor, it has a capacitor of permanent operation, which is in series with the auxiliary coil next to the start capacitor, which is removed from the circuit after the electric motor starts working. This condition causes extra torque. This type of electric motor can be designed for more efficiency. This electric motor is relatively expensive because of the constant working capacitors and its centrifugal starter and switch. This electric motor can be used in many applications that are expected from any other single-phase electric motor. These uses include machines related to wood, air compressors, high pressure water pumps, discharge pumps and other applications that require high torques.

Single-phase AC electric motor with shaded pole (with short circuit ring)

Types of single-phase electric motor with shaded pole have only one coil or main coil and no starter coil or coil. Starting is done by its special design that wraps a continuous copper ring around a small part of each pole of the electric motor. This shadow, which splits the pole into two pieces, causes a weaker magnetic field to be created in the shadowed area compared to the other part and next to it. The interaction between the fields makes the axis rotate. Because the electric motor with shaded pole does not have a start coil, start switch or capacitor, it is simple and cheap in terms of electricity. Also, its speed can be controlled simply by changing the voltage or by means of a coil with several different revolutions. The structure of the electric motor with shaded pole mechanically allows mass production.

This type of electric motor is known as disposable electric motor. This means that replacing them is cheaper than repairing them. Electric motors with shaded poles have many positive characteristics. But there are several flaws. Its low starting torque is usually ?? until the ?? It is the percentage of the nominal torque. They are electric motors with high loss that have a speed of about ? until the ?? They have a synchronous speed percentage. Generally, the efficiency of this type is very low (less than ?? percent). The low initial cost makes it suitable for lower power or lower duty applications. Perhaps the most widespread use of them is in multi-speed fans for home use. But the low torque makes the single-phase electric motor with shaded pole unusable for most industrial or commercial applications in which continuous work or more circulation periods are common.

Some of the reliable brands of single-phase electric motor

Prominent brands of single-phase electric motor, single-phase electric motor, Motogen, single-phase electric motor, Electrogen
single-phase electric motor motogen single-phase electric motor electrogen
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Elko single-phase electric motor, single-phase diesel electric motor

Elco single phase electric motor, diesel single phase electric motor

Three-phase electric motor

For applications requiring higher power, a three-phase AC (or multi-phase) electric motor is used. These dynamos use the phase difference between the phases of the multi-phase electric power source to create a rotating electromagnetic field inside them. Often, the rotor consists of a number of copper conductors embedded in steel. Through electromagnetic induction, a rotating magnetic field is induced in these conductors, which results in the creation of a balancing magnetic field and causes the axis of the electromotor to move in the direction of the rotation of the field.

In order for the axis of the three-phase electric motor to move, the axis must always rotate at a speed lower than the frequency of the power source applied to the electric motor. Otherwise, the balancing field will not be created in the rotor. The use of this type of electric motor in traction applications such as locomotives, where it is known as asynchronous traction motor, is increasing day by day. Separation field current is applied to the rotor windings to create a continuous magnetic field, which exists in the synchronous electric motor, the electric motor rotates simultaneously with the rotating magnetic field caused by the three-phase AC power. Synchronous electric motors can be

Almost most types of three-phase AC electric motors are of this type, whose rotor is squirrel cage type. Their power classification ranges from one third to several hundreds of horsepower. A three-phase electric motor of this type, which is in the range of one horse power and above, is cheaper compared to similar single-phase electric motors and can work with heavier loads at the time of starting.

Squirrel cage three-phase induction motor

A type of squirrel-cage motor with a sliding ring or a wire-wound rotor. While the stator in this electric motor is like a squirrel cage electric motor, it has a series of coils on its rotor, which are not short-circuited but end in a series of sliding rings. These coils are useful in adding external resistors and capacitors. The slip required to produce the ultimate maximum torque is directly proportional to the rotor resistance. In an electric motor with a slip ring, the effective resistance of the rotor is reduced by adding an external resistance between the slip rings. Therefore, it is possible to obtain more slip and also the final maximum torque at lower speeds.

This type of electric motor is ideal for constant static pressures in which the final torque must be produced at almost zero speed and the electric motor must accelerate to the rated speed in the shortest time and with the least current consumption. The amount of overload can increase the speed up to ?? Reduce the percentage of synchronous speed. Slow down to below ?? It reduces the percentage of efficiency due to energy loss in resistors. This type of electric motor is used in applications with rotation with different torques and speeds, such as printing presses, compressors, conveyor belts, lifts and elevators.

Authentic brands of three-phase electric motor

Three-phase electric motor producer brands, Siemens three-phase electric motor, Marelli three-phase electric motor
Siemens three-phase electric motor, Marley three-phase electric motor
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ABB three-phase electric motor, VEM three-phase electric motor
ABB three-phase electric motor, VEM three-phase electric motor
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WEG three-phase electric motor, ATB Sever three-phase electric motor
Three-phase electric motor VEG three-phase electric motor ATB Sur
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Three-phase electric motor Stream three-phase electric motor AEG
Three-phase electric motor, AEG three-phase electric motor
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Loher three-phase electric motor, Leroy Somer three-phase electric motor
Lohr three-phase electric motor, Leroy Sommer three-phase electric motor
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Motogen three-phase electric motor, Jemco three-phase electric motor
Motogen three-phase electric motor, Jemco three-phase electric motor
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Kaijieli three-phase electric motor Electrogen three-phase electric motor
Electrogen three-phase electric motor, Kaijili three-phase electric motor
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Guanglu three-phase electric motor, Ercem three-phase electric motor
Three-phase electric motor, Guanglu, three-phase electric motor, Arsem

Linear electric motor

A linear motor is basically an electric motor that has been changed from rotating to produce a linear force by creating a traveling electromagnetic field along its length instead of producing a rotational torque. Linear motors are mostly induction or stepping motors.

Stepper motor or servo

Another type of electric motor is the stepper motor or servo motor, in which an internal rotor, consisting of permanent magnets, is controlled by a group of magnets with external on-off electronic control. A stepping motor is a combination of a DC motor and a solenoid. Simple stepper motors are placed in specific positions by part of a gear system, but controlled stepper motors can rotate very slowly. Computer controlled stepper motors are one form of position regulation systems, especially when they are part of a digital system with load command control.

Electric motor license plate or electric motor license plate

No: The engine model that is usually determined by the work of the house.
Type: engine name, by having the engine name and referring to the manufacturer, you can get more information about the engine.
AMPS: The maximum virtual current that the motor needs to work.
V: is the working voltage of the electric motor, which should not be applied more or less voltage to the coils of the electric motor. If there is an asterisk (Y) or a triangle (?), the voltage is used in the same connection (for example, the working voltage of the above motor is 415 V in star mode).
HERTZ: specifies the working frequency of the motor, usually the working frequency of the motors is 50 or 60 Hz.

Note: The speed of an electric motor is related to its frequency. Therefore, the electric motor which supposedly has 1500 revolutions at the frequency of 50 Hz, does not have 1500 revolutions at the frequency of 60 Hz.

DATE: It specifies the engine manufacturing date.
R.P.M: indicates the rotation of the electric motor in one minute on the output power.
KW: shows the power value of the electric motor.

Note: If 220/380 V was written on an electric motor, it means that this electric motor is used in the 110 volt grid that is used in some countries, and in countries that have a voltage of 220 volts (voltage between one phase and zero) it should be triangular. Like Iran, it should be closed like a star.

IP = the level of protection of the electric motor against dust according to the table below.
P.H = types of protection according to DIN 40050 standard
P00 = open without protection against contact with foreign bodies and water, in this case the engine must be kept in a covered space.
P10 = Protected against contact with hands and large external objects - protection against water, the engine can work in the arm space under rain.
P11= protected against hand contact and large foreign objects - protected against water
P20 = Protected against finger contact and medium-weight objects without protection against water, a suitable cover must be provided for the engine.
P21 = Protected against finger contact and medium weight objects - waterproof
P22 = Protected against finger contact and medium-weight objects - Protected against vertical or inclined water discharge at an angle of more than 30 degrees to the horizon.
P30 = Protected against contact with tools, etc., and lightweight foreign objects - no protection against water
P31 = Protected against contact with tools, etc., and lightweight foreign objects - waterproof
P32 = Protected against contact with tools, etc., and light-weight external objects - Protected against vertical or inclined water discharge at an angle of more than 30 degrees to the horizon.
P40 and above: Protected against all external factors

There may be other information on the engines, the user can find out about them by referring to the engine catalog.

The standard defined in relation to the IP of electric machines

The letter W is used after the two declared figures in cases where the electric machine is designed with an open circuit with an air cooling system and works in atmospheric conditions in such a way as to prevent the penetration of rain and wind-borne particles under certain conditions. The electric machine reduces and controls, and the small amount entered inside does not affect its performance, such as IP13W.

When only one feature of the IP indexes is important for the consumer, the unimportant index is marked with the letter X, such as IP2X, which only indicates the degree of protection for life, or IPX4, which indicates the degree of protection against moisture.

The first digits: the degree of life protection defined and its characteristics
The degree of life protection is defined and its characteristics are the first characteristics of the operating conditions
0 car is not protected.
1 Protected against human hands or objects with a diameter of more than 50 mm
2 Protection against human fingers or objects with a diameter greater than 12 mm
3 protection against electric tools with a diameter of more than 2.5 mm
4 protection against thin wires and insulation with a diameter of more than 1 mm
5 protection done inside the electric machine against excessive dust that has been harmful to it.
6 Complete protection against dust

The second digits: the degree of protection against defined humidity and its characteristics
The degree of protection against moisture is defined and the characteristics of that degree of protection are performed
0 The car has no protection against moisture.
1 The electric motor is protected against water dripping vertically.
2 The electric motor is protected against water dripping with a deviation of 15 degrees from the vertical.
3. The electric motor is protected against water leakage.
4. The electric motor is protected against splashing water.
5. The electric motor is protected against water ingress.
6. The electric motor is protected against flooding.
7. The electric motor is protected against the destructive effects of immersion.
8. The electric motor has the ability to be permanently immersed in water.