Stator

Electronic communication involves the use of different components, each needed for a different purpose. One such device is a stator which forms an essential part of the motors used in everyday appliances. In this article, we will study stators and their categorization based on their use. We will also discuss the diagram of a stator to ensure better conceptual clarity of the working of the stator.

The later parts of the article will cover the components of the stator and the design of the stator made using these components. Once, we have covered the basics of stators, we will shift towards the advantages offered by a stator and how are they used in everyday appliances. The last section will talk about the limitations of stators and will conclude with some frequently asked questions.

Most of you would know that a stator is a device that is used to enhance the performance of motors making it a critical part of the motor. Here is the formal definition of a stator

The stator is the stationary part of the motor that is defined by the number of windings it has. The polarity of the stator is determined by the AC power supplied to it.

The main purpose of the stator is to create a magnetic field depending on the voltage applied and then this voltage is used to generate an electromagnetic field across the rotors of the motor.

Important Terminologies

• Motor: A motor is device that performs the task of converting electrical energy into some kind of mechanical energy like rotation of armature.
• Electric Field: An electric field is generated in the stator as a result of power supplied to the stator. The field exerts force of current-carrying conductors.
• Rotor: It is the rotating part of the motor apart from the stationary part.
• Armature: It is a current carrying conductor present in the motor which rotates as a result of magnetic field activation in the stator.
• Torque: The force experienced armature is known as torque which causes the rotating motion of the armature. It is given by the cross product of distance and force.

Here is what the basic diagram of the stator looks like

You can observe the stator consists of three major components namely the Outer Frame, Core, and, Windings. Let us study them individually

• Outer Frame: The outer frame is a base that is used to provide support to the whole setup of the motor. The stator is usually a metallic or a plastic case that has high tensile strength.
• Core: The core is used to measure and handle the unequal magnetic field in the motor. This process is used for generating eddy current and managing the hysteresis losses. The core is attached to the frame for support and connections in the core are made using stampings at different points in the frame.
• Windings: The windings are present around the core to provide the necessary power supply to the core. The windings can come in various designs like three-phase or four-phase designs depending on the motor requirements. The winding can be created with any number of poles depending on the speed of the motor needed. Higher poles indicate lesser speed whereas lesser poles indicate better speed.

Depending on the configuration and number of windings in the stator, we can divide the stator into three types mentioned below:

• Single Phase Stator
• Three Phase Stator
• Five Phase Stator

Single Phase Stator

If the stator is a part of a single-phase motor and the motor consists of one stator part then it is known as single-phase stator. With an increase in number of phases, the efficiency of motor increases therefore, single-phase motor is an unbalanced motor due to high currents and excessive heating. It even faces the problem of excessive noise generation. Here is the diagram for this stator type

Three Phase Stator

If the stator is a part of a three-phase motor and the motor consists of three stator parts then it is known as three-phase stator. With an increase in number of phases, the efficiency of motor increases therefore, three-phase motor is better than single-phase motor in terms of currents and excessive heating. Due to more number of windings, the noise generation is comparatively less. Here is the diagram for this stator type

Five Phase Stator

If the stator is a part of a five-phase motor and the motor consists of five stator parts then it is known as five-phase stator. With an increase in number of phases, the efficiency of motor increases therefore, this motor has great efficiency and power delivered in unbalanced. Due to more number of windings, the noise generation is very low because current gets shared amongst the windings. Here is the diagram for this stator type

Let us understand the working principle behind a stator

• The stator is connected to a three-phase power supply that supplies power to the motor at different intervals depending on the phase.
• When the stator receives the power, it generates a magnetic field. This rotating magnetic field is carefully designed depending on the need of the device for example it solves different purposes in motor, generator, and levitation devices.
• When the current carrying conductor i.e. armature is present in the magnetic field, it experiences a force that causes it to rotate.
• The rotation of armature is responsible for the current generated in the coil. This is how the magnetic field is used for current generation in motor.

Let us study the difference between a stator and a rotor.

Let us see some advantages of stator

• The rigid design of the stator is used for providing stable support to the design of the machine.
• The stationary magnetic field in the stator is used to ensure minimal energy loss and ensuring efficient energy conversion.
• Depending on the requirements of the machine, the design of the stator can be customized given precise control over the stator.
• The stators are designed to handle various withered conditions like high temperatures, electrical stresses, and mechanical wear, ensuring longevity and reliability.
• The stator has no moving parts which means that the stator has minimal maintenance cost.

Let us see some disadvantages of a stator

• With the increase in the specifications of the motor, the design of the stator keeps getting complicated. Cheap motors are easy to design but high performance motors are complicated to design.
• The design of the motor can get damaged after a period of time indicating a low durability which is mainly attributed to the overheating in the stator design.
• There are many losses associated with the stator which are due to the electrical resistance of the coil. These can affect the performance of the stator.
• The speed at which a machine operates is controlled by the stator design therefore, a complicated stator design will reduce the speed of operation of the device.
• There are certain threats and failures associated with the stator such as insulation breakdown or winding faults increasing the maintenance cost of the machine.

Let us see some applications of a stator

• It is often used as a magnet in the electromagnetic field of a motor depending on the design.
• It is used in a generator to perform the task of driving the electric current from the rotating magnetic field generated.
• It is often used as a guiding system like in fluid powered devices where it provides the path for the fluid to flow into the system.
• Stators are used in transformers where they regulate the power supply by controlling the power distribution.
• The ability of a stator to store magnetic fields is used in magnetic levitation systems, especially maglev trains that need magnetic fields for levitation purposes.

We have seen that the stator forms an essential part of the motor since it provides the support needed for the essential components like windings, and the core. Based on the needs and requirements, the stator can come in various designs with different power supplies. Some of the designs have been explained above through the diagrams. The ease of using the stator makes it the best choice for many appliances like.

Despite, the features offered by the stator, there are some limitations in the design, and improvements are being made to the design. Readers are advised to go through the frequently asked questions in case of any doubts.

What is the component that is present in motor apart from stator?

The rotor is another important part of motor apart from stator that forms the rotating part of the electric motor.

What is meant by a three-phase supply of motor?

Since electricity used in everyday life is alternating current that has a phase and a magnitude therefore, a three-phase supply indicates three conductors that are used to supply power at three different phases.

What is meant by insulating the wires?

Heavy insulation is used for stator which means insulating wires are used to coil up the stator to ensure no current flows on the outside of the stator.