Electric motors are devices that transform electrical energy into mechanical energy. The medium of this energy transformation in electric motors is the magnetic field. There are different types of electric motors and each type has different components whose structure determines the interaction of electric and magnetic flows that cause the force or torque of the motor.

The fundamental principle that describes how a force is generated by the interaction of a point electric charge q in electric and magnetic fields is the Lorentz force:[8]​.

where:.

In the case of a purely electric field the expression of the equation reduces to:.

The force in this case is determined only by the charge q and the electric field. It is the Coulomb force that acts along the conductor causing electrical flow, for example in the stator coils of induction machines or in the rotor of direct current motors.

In the case of a purely magnetic field:.

The force is determined by the charge, the density of the magnetic field, and the speed of the charge. This force is perpendicular to the magnetic field and the direction of the speed of the charge. Normally there are many charges in motion so it is convenient to rewrite the expression in terms of charge density and then force density (force per unit volume) is obtained:

The product is known as current density (amperes per square meter):.

Then the resulting expression describes the force produced by the interaction of current with a magnetic field:.

This is a basic principle that explains how forces originate in electromechanical systems such as electric motors. However, the complete description for each type of electric motor depends on its components and construction.

DC motors are classified according to the way they are connected, into:.

In addition to the above, there are other types that are used in electronics:

There are three types, the asynchronous motor being the most used in the industry and the one that requires the least maintenance:.

Contenido

Los motores eléctricos se utilizan en la gran mayoría de las máquinas modernas. Su reducido tamaño permite introducir motores potentes en máquinas de pequeño tamaño, por ejemplo taladros o batidoras. Su elevado par motor y alta eficiencia lo convierten en el motor ideal para la tracción de transportes pesados como trenes; así como la propulsión de barcos, submarinos y dúmperes de minería, a través del sistema diésel-eléctrico.

Change of direction of rotation

To change the direction of rotation of alternating current electric motors, follow a few simple steps such as:

For direct current motors it is necessary to reverse the starting torque contacts.[9]​.

The energy efficiency of electric motors has been standardized by international organizations. According to the IEC 60034-30-1 standard,[10] AC motors are classified into four efficiency levels:

These levels allow the energy performance of the motors to be compared and facilitate the implementation of regulations to reduce electricity consumption in the industry.[11]​.

Three-phase synchronous there are two ways to vary the speed, one is by varying the frequency using special electronic equipment and the other is by varying the polarity thanks to the design of the motor. The latter is possible in separate winding motors or Spinner connection motors,[12]​ but it is only possible to have a limited polarity change, for example, two and four poles.

An electrostatic motor is based on the attraction and repulsion of electrical charge. Typically, electrostatic motors are twice as large as conventional coil-based motors. They typically require a high-voltage power supply, although small motors employ lower voltages. In contrast, conventional electric motors employ magnetic attraction and repulsion, and require high current at low voltage. In the 1750s, Benjamin Franklin and Andrew Gordon developed the first electrostatic motors. Electrostatic motors find frequent use in micro-electromechanical systems (MEMS) where their drive voltages are below 100 volts, and where moving charged plates are much easier to manufacture than coils and iron cores. The molecular machinery that powers living cells is often based on linear and rotary electrostatic motors.

A piezoelectric motor or piezomotor is a type of electric motor based on the shape change of a piezoelectric material when an electric field is applied. Piezoelectric motors use the inverse piezoelectric effect whereby the material produces acoustic or ultrasonic vibrations to produce linear or rotary motion.[13]​ In one mechanism, elongation in a single plane is used to make a series of stretches and positions, similar to how a caterpillar moves.[14]​.

An electrically powered spacecraft propulsion system uses electric motor technology to propel spacecraft in outer space. Most systems are based on electrical acceleration of the thruster to high speed, while some systems are based on electrodynamic belt principles of propulsion to the magnetosphere.[15]​.

Electric motors are devices that transform electrical energy into mechanical energy. The medium of this energy transformation in electric motors is the magnetic field. There are different types of electric motors and each type has different components whose structure determines the interaction of electric and magnetic flows that cause the force or torque of the motor.

The fundamental principle that describes how a force is generated by the interaction of a point electric charge q in electric and magnetic fields is the Lorentz force:[8]​.

where:.

In the case of a purely electric field the expression of the equation reduces to:.

The force in this case is determined only by the charge q and the electric field. It is the Coulomb force that acts along the conductor causing electrical flow, for example in the stator coils of induction machines or in the rotor of direct current motors.

In the case of a purely magnetic field:.

The force is determined by the charge, the density of the magnetic field, and the speed of the charge. This force is perpendicular to the magnetic field and the direction of the speed of the charge. Normally there are many charges in motion so it is convenient to rewrite the expression in terms of charge density and then force density (force per unit volume) is obtained:

The product is known as current density (amperes per square meter):.

Then the resulting expression describes the force produced by the interaction of current with a magnetic field:.

This is a basic principle that explains how forces originate in electromechanical systems such as electric motors. However, the complete description for each type of electric motor depends on its components and construction.

DC motors are classified according to the way they are connected, into:.

In addition to the above, there are other types that are used in electronics:

There are three types, the asynchronous motor being the most used in the industry and the one that requires the least maintenance:.

Contenido

Los motores eléctricos se utilizan en la gran mayoría de las máquinas modernas. Su reducido tamaño permite introducir motores potentes en máquinas de pequeño tamaño, por ejemplo taladros o batidoras. Su elevado par motor y alta eficiencia lo convierten en el motor ideal para la tracción de transportes pesados como trenes; así como la propulsión de barcos, submarinos y dúmperes de minería, a través del sistema diésel-eléctrico.

Change of direction of rotation

To change the direction of rotation of alternating current electric motors, follow a few simple steps such as:

For direct current motors it is necessary to reverse the starting torque contacts.[9]​.

The energy efficiency of electric motors has been standardized by international organizations. According to the IEC 60034-30-1 standard,[10] AC motors are classified into four efficiency levels:

These levels allow the energy performance of the motors to be compared and facilitate the implementation of regulations to reduce electricity consumption in the industry.[11]​.

Three-phase synchronous there are two ways to vary the speed, one is by varying the frequency using special electronic equipment and the other is by varying the polarity thanks to the design of the motor. The latter is possible in separate winding motors or Spinner connection motors,[12]​ but it is only possible to have a limited polarity change, for example, two and four poles.

An electrostatic motor is based on the attraction and repulsion of electrical charge. Typically, electrostatic motors are twice as large as conventional coil-based motors. They typically require a high-voltage power supply, although small motors employ lower voltages. In contrast, conventional electric motors employ magnetic attraction and repulsion, and require high current at low voltage. In the 1750s, Benjamin Franklin and Andrew Gordon developed the first electrostatic motors. Electrostatic motors find frequent use in micro-electromechanical systems (MEMS) where their drive voltages are below 100 volts, and where moving charged plates are much easier to manufacture than coils and iron cores. The molecular machinery that powers living cells is often based on linear and rotary electrostatic motors.

A piezoelectric motor or piezomotor is a type of electric motor based on the shape change of a piezoelectric material when an electric field is applied. Piezoelectric motors use the inverse piezoelectric effect whereby the material produces acoustic or ultrasonic vibrations to produce linear or rotary motion.[13]​ In one mechanism, elongation in a single plane is used to make a series of stretches and positions, similar to how a caterpillar moves.[14]​.

An electrically powered spacecraft propulsion system uses electric motor technology to propel spacecraft in outer space. Most systems are based on electrical acceleration of the thruster to high speed, while some systems are based on electrodynamic belt principles of propulsion to the magnetosphere.[15]​.