Structure of Electric Motors

Structure of Electric Motors


    Electric motors are devices that convert electrical energy into mechanical energy. The general, the electric motor structure consists of two basic components, a rotor (rotating part) and a stator (stationary part). The rotor provides motion by rotating in a magnetic field and is usually located on a shaft. The stator consists of magnetic coils surrounding the rotor and creating a magnetic field. Electrical energy is provided by a three-phase alternating current applied to the stator coils. This current rotates the rotor by creating a magnetic field. Electric motors can be of different types and have different features according to their intended use. Motors are designed according to factors such as efficiency, power, and speed control. They are also supported by additional components such as bearing systems, cooling mechanisms, and protective coatings. The structure of electric motors is based on the principle of converting electrical energy into mechanical energy and is widely used in many areas such as industrial, household appliances, and vehicles.

    What is the Structure of an Electric Motor?

    Although electric motors have many different types and designs, their basic structure is similar. The structure of a typical electric motor usually consists of a rotor, a stator, and a commutator. The rotor is in the form of a shaft equipped with magnets or electromagnets with a magnetic field. The stator contains permanent magnetic fields placed around the rotor and usually consists of coils. When an electric current is applied to the coils of the stator, the magnetic fields interact and the rotor begins to rotate. The commutator is a device that directs the movement of the rotor and ensures that it rotates in the right direction. In this way, electric motors convert electrical energy into mechanical energy and can be used in applications ranging from household appliances to industrial machinery.

    What are the Electric Motor Features?

    Electric motors have many features. First of all, their efficiency is high, that is, their rate of converting electrical energy into mechanical energy is quite good. It also provides speed adjustability, that is, they can be operated at different speeds. Electric motors require little maintenance and have a long service life. They also have fast response capabilities, providing fast start and stop functions. Motor power can be varied according to different needs and they generally run quietly. They are considered environmentally friendly as they produce no waste gas or emissions. Electric motors are a preferred option in terms of energy efficiency, flexibility, and various application areas.

    End Connection Box in Electric Motors

    All terminal boxes comply with IP 65 protection degrees and are placed on the front of the motor so that it can be rotated 180° so that the main cable entry can be made easily from both sides. In general construction, the motors have 6 fixed terminals and there is a ground screw in the terminal box in direct contact with the body. The terminal boxes of frame size 56...180 motors are made of high-quality reinforced Polyamide, and those of frame size 200...450 are corrosion-resistant pressure die-cast aluminum alloy. On request, the terminal boxes of motors in frame size 71...132 are made of corrosion-resistant pressure die-cast aluminum alloy.

    Cable Entry in Electric Motors

    In electric motors, the cable entry is usually located on the end connection box or motor housing. The cable entry is realized using glands manufactured by EN 60423 and DIN EN 50 262 or optionally using ethane glands with protection class IP 68. This ensures the correct and safe connection of the main cable inside or outside the motor. Various cable entry options are available for different motor designs and sizes.

    Bearings in Gamak Electric Motors 

    High-quality, sound-controlled deep groove ball bearings (DIN 625) or cylindrical roller bearings (DIN 5412) are used in electric motors. Single-row deep groove ball bearing design is offered as standard in GAMAK electric motors. In motors with frame size 132 and above, if the radial force applied to the motor shaft end is above a certain value, a cylindrical roller bearing design with greater radial force carrying capacity should be selected. If the axial force applied to the motor shaft end is above certain values, a special design motor may be required.

    Protective Measures in Gamak Electric Motors 

    The following protective measures should be taken against extremely harsh climatic conditions such as working in an open environment, wet humidity, corrosive chemicals, or coastal atmosphere.
    • Special protective paint should be used.
    • The degree of protection IP 56 must be stipulated.
    • Winding heads should be protected with a special lacquer against excessive humidity.
    • In all kinds of vertical installations open to the atmosphere, the following solutions should be applied to prevent water infiltration from the shaft edges into the motor, in a way that does not hinder the motor's cooling system:
    • Shaft end down: Covered with an additional protective cover (Canopy),
    • Shaft end up: Covered with a special protective cover or fitted with a bearing seal.

    Measures to be taken against water condensation in Gamak Electric Motors 

    The water discharge holes, which are closed with plastic plugs, are opened to the lowest point of the housing by the construction type/installation order of the motor and should always be kept clean. If the plugs are removed, the degree of protection of the motor enclosure is IP 44.
    However, it is the most appropriate method to prevent water condensation by keeping the inside body temperature of fully closed motors at the prescribed level. For this, we recommend the following applications.
    Two heaters should be placed on the front and rear winding heads of the motor with the total powers recommended in the table below. However, the heater must be disabled before starting the motor.

    Another solution is to apply a voltage as low as 5...10% of the motor supply voltage and a current of 20...30% of the rated current to the U1 and V1 terminals using an auto-transformer after the voltage supplying the motor is cut off. 

    Cooling in Gamak Electric Motors 

    motors of size 56 do not have a cooling fan (IC 410), they cool by free dissipation. motors of size 63...450 are externally cooled by a cooling fan operating in a perforated case cover made of sheet steel (IC 411). On the back surface of the propeller case bowl, holes suitable for the conditions of the standard test finger and suitable for sufficient air passage are made. The cooling fans of the 63...355 frame size motors are made of high-quality reinforced Polyamide material, and the 400 and 450 frame sizes are made of aluminum alloy. The cooling fan is fixed to the shaft output at the rear of the motor and operates regardless of the direction of rotation.

    Cable Input in Gamak Electric Motors 

    Cable entries to the terminal box are provided using glands manufactured by EN 60423 and according to DIN EN 50 262 or using waterproof (IP 68) glands upon special request.

    You can use the GAMAK electric motor selection tool to select the right electric motor for your needs.

    For more information, you can contact our experts.

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