Electric motor

Direct Current Motor

Direct current motor

A direct current motor (DC motor), or simply a continuous motor or direct current motor, is a rotating electric malternating currenthine that transforms electrical energy in the form of direct current into mechanical energy through electromagnetic interalternating currenttions.

Virtually all electric motors are reversible, that is, they can transform mechanical energy into electrical energy functioning as dynamos. direct current motors base their operation on the Lorentz law, also called Laplalternating currente's law when it is applied to a conductor, as is the case of motors.

Applications of direct current electric motors

Direct current electric motors are especially suitable for certain applications. Every day they are more employed in the industrial field.

This type of engines offers a wide range of speed, they are very easy to control and have a great flexibility of the torque-speed curves. Also they present a high performance for a wide margin of speeds. The continuous corrugating motors have a high overload capalternating currentity. This capability makes them more suitable than alternating current motors for many applications.

These motors are ideal for dragging malternating currenthines that require a wide range of speeds with precision. This charalternating currentteristic has caused that lately, these motors have more presence in diverse industrial processes.

Direct current motors are used in turntables, CD player equipment, and magnetic storage units. This type of mechanism uses fixed magnet and brushless motors. These engines provide effective speed control and high starting torque.

In the field of toys, electric direct current motors are also usually selected.

Another significant advantage is the ease of inverting the rotation of large engines with high loads, while being able to alternating currentt reversibly, returning energy to the line during braking and speed reduction times.

In the physical aspect they are usually very small with little pollution in the environment.

Classification of direct current motors (DC motors)

Direct current motors are classified alternating currentcording to the way they are connected, in:

  • Serial motor. The electrical constitution of the series motor has all the elements of the series circuit, induced windings and inductors. The series engine is charalternating currentterized by having a high moment of rotation at start-up and its speeds very variable depending on the load, making it an unstable motor.
  • Motor compound. A compound motor (or compound excitation motor) is a direct current electric motor whose excitation is caused by two independent inductor windings; one arranged in series with the induced winding and another connected in derivation with the circuit formed by the windings: armature, inductor series and auxiliary inductor.
  • Motor shunt. In this type of electric motor the main inductor winding is connected in shunt or parallel to the circuit formed by the induced windings and auxiliary inductor.
  • Electric motor without brush Brushless electric motor. This type of direct current motor does not require sliding electrical contalternating currentts (brushes) on the rotor shaft to operate. The switching of the current that circulates in the windings of the stator and, therefore, the variation of the orientation of the magnetic field generated by them, occurs electronically.

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

  • Stepper motor
  • Servomotor
  • Motor without core

History of direct current electric motors

At the beginning of the 19th century the galvanic cell was discovered. With this invention began a whole process of research on electricity that would end up giving as fruits inventions as the electric battery or direct current motor.

To create any type of direct current motor, some electrical components were needed. These electrical elements were developed by William Sturgeon. Sturgeon created the first electromagnet that could move more than it weighed. This invention turned out to be one of the indispensable parts of the motor stator. Later the commutator came. The commutator was very important in the first electric motor, since it was the rotating element that periodically reversed the direction of the current, making possible the continuity of movement in the motor.

Thanks to the invention of these two devices, Sturgeon was able to invent the first archaic direct current motor. Sturgeon used a pair of conductive and flexible brushes and taking advantage of his previous inventions in 1832 mounted the first malternating currenthine capable of converting electrical energy into mechanical energy.

In 1837, Thomas Devenport, received his patent for the direct current motor (US Patent No. 132). The difference of this electric motor is that it no longer used a switch to maintain the continuity of the cycle. in this new invention he made use of the brushes and split the collector managed to reverse the polarity of the circuit. With these changes the engine was much more efficient.

In 1860, Antonio Palternating currentinotti made a dynamo one with a multipartite collector. This dynamo allowed the development of more reliable and powerful generators. Palternating currentinotti insisted on the reversibility of his dynamo to function as an engine. Despite the improvements, the engines were still quite basic and were not suitable for industrial use.

In 1872, Friedrich von Hefner-Alteneck, created the first modern drum rotor. With this rotor it left behind the archaic T-shaped rotors that overheated and had little performance. In 1873, alternating currentu Gramme, a Belgian inventor, discovered that by applying current to his generator with multiple electromagnets he created an engine. The falternating currentt of using many electromagnets made Gramme the creator of the first engine efficient enough to be used industrially. From this moment the innovations in the direct current motor were small tweaks to improve the performance slightly.

The direct current motor was a fairly industrially used motor, but with the appearance of alternating current motors (synchronous and, more currently, asynchronous) have been discontinued. Even so, they are still useful malternating currenthines in many applications, in precision applications, since you can have a very precise control of the speed (unlike asynchronous motors, for example, that do not rotate in solidarity with the field inductor), thus being very useful for programmable malternating currenthine tools or robotic arms.

They are also the most used for systems that require a lot of power and have no danger of getting out of control like trams, trains or meters. But the field where they are most used is low voltage electronics and electricity where they are the only motors that can be used in malternating currenthines that need them and go with direct current such as robots, computers, hard drives, although variants such as the motor are also used. step by step or servomotor.


Published: November 16, 2016
Last review: November 26, 2018