The rotor and stator are the most important components in an electric machine. They refer to the rotating portion of an electric motor, surrounded by spinning blades. This can apply to rotating turbine blades or other items enclosed by moving objects. These components help in the formation of electromagnetic forces due to the interaction between them.
The rotating system is activated in electrical or mechanical energy by the generated electromagnetic force. Both components are incorporated into the same machine. However, there are varied functions and characteristics between rotor and stator.
Rotor vs Stator
The main difference between a rotor and a stator is that a rotor is the rotating or moving part of an electric motor. On the other hand, a stator is the stationary or fixed part of an electric motor.
The rotor is the rotating component of an electric motor or machine that generates energy. It is situated within the center of the stator. The DC supply stimulates the rotor winding. The field winding creates a steady magnetic field in the body of the rotor.
A stator is a stationary electrical component found in electric machines. The stator is made up of three parts: the stator frame, stator core, and stator winding. The stator’s core is supported by the frame, which also protects the three-phase winding of the stator. The spinning magnetic field induced by the three-phase supply is carried by the stator core.
Comparison Table Between Rotor and Stator
| Parameters of Comparison | Rotor | Stator |
| Definition | The rotor can be an element that moves inside the device. | A stator can be an element that is permanent on the device. |
| Origin | Rotor gets its name from the part that moves in the machine. | Stator gets it’s name from the fixed portion of the machine. |
| Construction | The rotor is inside the body of the stator. | The stator is outside the motor. |
| Main Parts | Rotor winding, Rotor core are the main parts of the Rotor. | The outer frame, stator winding, and stator frame are the main components of the stator. |
| Power Supply | The rotor requires a DC source to create a rotating field. | The stator’s winding requires an AC supply. |
| Weight | The rotor winding is lightweight when compared to the stator. | The stator winding is a bit heavier when compared to the rotor. |
| Winding | The winding arrangement is simple and is small than the stator. | The winding arrangement is complex and is large than the rotor. |
| Insulation | The rotor winding has a low level of insulation. | The stator winding has a high degree of insulation to carry heavy current. |
| Friction Loss | There are fewer friction losses in the rotor. | There are more friction losses in the stator. |
| Cooling | The rotor has a complex cooling system. | The stator has a simple cooling system. |
What is Rotor?
The word rotor is derived from ” rotating ” and refers to the main spinning component of an electrical machine. The connection of the windings and magnetic fields causes torque to be generated around the rotor’s axis, giving a rotational movement.
The rotor core is made of electrical laminated steel sheets. Aluminum windings are produced together with short-circuit rinds inside the rotor slots. This is achieved by drilling holes in the lamination to allow channels to form through the rotor core when layered. These tubes will fill with aluminum during the casting process, shaped like a squirrel cage when combined with the short-circuit rings.
What is Stator?
The stator is a fixed component in electromagnetic circuits. The stator can operate as field magnets that interact with the rotor to create motion or as brushless motors that work with the rotor’s moving field coils in many combinations. Permanent magnets, which are both a field coil or winding, are used to keep fields aligned.
The stator of an AC motor is made of thin steel laminations of the core. The windings are coils of insulated wire put into the core and connected directly to the power supply. The electricity is delivered to both of them and is combined to form an electromagnet. The field windings and poles that make up the magnetic circuit with the rotor are carried by the stator in DC motors.
It is a stationary component of a rotating system present in electrical generators, motors, and sirens. Energy is transferred to or from the rotating component of the system through the stator. The stator drives the revolving armature of an electric motor. It transforms the rotating magnetic field into an electric current in a generator. The stator directs fluid flow to or from the rotating element of the system in fluid power systems.
Main Differences Between Rotor and Stator
- The rotor is the moving component of the machine, whereas the stator is the fixed part of the machine.
- The rotor is of two parts; the rotor core and field winding, while the stator is of three parts; the stator core, stator winding, and outer frame.
- The DC supply stimulates the rotor, whereas a three-phase power supply powers the coils of the stator.
- The arrangement of the rotor’s coils are simple, whereas the winding arrangement of the stator is more complicated than the rotor.
- The rotor has poor insulation, while the stator is well insulated due to the high voltage induced in the stator winding.
- The field winding of the rotor is small in size when compared to the stator winding, which is much larger to carry heavy current.
- The rotor has a complex cooling system, while the stator has a better cooling system than the rotor as it is immovable.
- The rotor has less friction loss, whereas the stator has high friction loss than the rotor as it is a bit heavy than a rotor.
Conclusion
The rotor and stator of an electric motor have many significant distinctions. The rotor of a machine moves, while the stator remains permanent. The rotor is located inside the body of the stator, whereas the stator is located on the outer part of the machine. The rotor spins within the rotating magnetic field, and the stator winding, which provides the revolving magnetic field, receives a three-phase power supply. An EMF is generated due to the interaction between the rotor and stator magnetic fields.
References
- https://www.sciencedirect.com/science/article/pii/S0888327013002331
- https://asmedigitalcollection.asme.org/GT/proceedings-abstract/GT2002/3610X/287/292270
- https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.22718