Electric motor, any of a class of devices that convert electricity to mechanical energy, usually by using electromagnetic phenomena.
What is a power motor?
How do you bring points in motion and keep them moving without moving a muscle? While steam engines create mechanical energy using sizzling steam or, more precisely, steam pressure, electric motors use electric energy as their resource. For this reason, electric motors are also called electromechanical transducers.
The counter piece to the electric engine is the generator, which has a similar structure. Generators transform mechanic motion into electric power. The physical basis of both procedures is the electromagnetic induction. In a generator, current can be induced and electricity is created when a conductor is within a shifting magnetic field. Meanwhile, in an electric motor a current-transporting conductor induces magnetic areas. Their alternating forces of attraction and repulsion produce the basis for generating motion.
How does an electric motor work?
Motor housing with stator
Motor housing with stator
Generally, the heart of a power motor consists of a stator and a rotor. The word “stator” comes from the Latin verb “stare” = “to stand still”. The stator may be the immobile part of an electric motor. It really is firmly attached to the equally immobile housing. The rotor on the contrary is installed to the engine shaft and will move (rotate).
In the event of AC motors, the stator includes the so-called laminated core, which is wrapped in copper wires. The winding works as a coil and generates a rotating magnetic field when current is certainly flowing through the cables. This magnetic field created by the stator induces a current in the rotor. This current then generates an electromagnetic field around the rotor. Consequently, the rotor (and the attached electric motor shaft) rotate to check out the rotating magnetic field of the stator.
The electric motor serves to apply the created rotary motion to be able to drive a equipment unit (as torque converter and speed variator) or even to directly drive a credit card applicatoin as line motor.
What types of electric motors are available?
All inventions began with the DC electric motor. Nowadays nevertheless, AC motors of varied designs are the mostly used electrical motors in the industry. They all have a common result: The rotary motion of the electric motor axis. The function of AC motors is based on the electromagnetic operating theory of the DC engine.
As with most electrical motors, DC motors consist of an immobile component, the stator, and a moving element, the rotor. The stator consists either of an electric magnet utilized to induce the magnetic field, or of long lasting magnets that Ac Induction Motor constantly generate a magnetic field. Within the stator is where in fact the rotor is definitely located, also known as armature, that is covered by a coil. If the coil is linked to a way to obtain direct current (a battery, accumulator, or DC voltage supply unit), it creates a magnetic field and the ferromagnetic core of the rotor turns into an electromagnet. The rotor can be movable mounted via bearings and may rotate so that it aligns with the attracting, i.e. opposing poles of the magnetic field – with the north pole of the armature opposing of the southern pole of the stator, and the other method round.
In order to arranged the rotor in a continuing rotary movement, the magnetic alignment must be reversed over and over. This is achieved by changing the current direction in the coil. The motor has a so-called commutator for this purpose. Both supply contacts are connected to the commutator and it assumes the task of polarity reversal. The changing attraction and repulsion forces ensure that the armature/rotor proceeds to rotate.
DC motors are mainly used in applications with low power ratings. These include smaller tools, hoists, elevators or electrical vehicles.
Asynchronous AC motors
Instead of direct current, an AC motor requires three-phase alternating current. In asynchronous motors, the rotor is usually a so-called squirrel cage rotor. Turning outcomes from electromagnetic induction of the rotor. The stator includes windings (coils) offset by 120° (triangular) for every stage of the three-stage current. When linked to the three-stage current, these coils each build up a magnetic field which rotates in the rhythm of the temporally offset range frequency. The electromagnetically induced rotor is definitely carried along by these magnetic areas and rotates. A commutator much like the DC electric motor is not needed in this way.
Asynchronous motors are also known as induction motors, because they function only via the electromagnetically induced voltage. They run asynchronously since the circumferential swiftness of the electromagnetically induced rotor never reaches the rotational swiftness of the magnetic field (rotating field). For this reason slip, the efficiency of asynchronous AC motors is lower than that of DC motors.
More on the framework of AC motors / asynchronous motors and upon what we offer
AC synchronous motors
In synchronous motors, the rotor has permanent magnets instead of windings or conductor rods. In this manner the electromagnetic induction of the rotor can be omitted and the rotor rotates synchronously without slip at the same circumferential quickness as that of the stator magnetic field. Effectiveness, power density and the feasible speeds are thus considerably higher with synchronous motors than with asynchronous motors. However, the look of synchronous motors is also a lot more complex and time-consuming.
Additional information about synchronous motors and our portfolio
As well as the rotating machines that are mainly used on the market, drives for actions on straight or curved tracks are also required. Such motion profiles occur primarily in machine tools and also positioning and managing systems.
Rotating electric motors can also convert their rotary motion into a linear motion with the aid of a gear unit, we.e. they are able to cause it indirectly. Often, however, they do not have the required dynamics to realize particularly demanding and fast “translational” movements or positioning.
That’s where linear motors come into play that generate the translational motion directly (direct drives). Their function can be derived from the rotating electric motors. To do this, imagine a rotating motor “exposed”: The previously circular stator becomes a flat travel distance (monitor or rail) which is certainly protected. The magnetic field then forms along this path. In the linear motor, the rotor, which corresponds to the rotor in the three-phase motor and rotates in a circle there, is stopped the travel range in a straight range or in curves by the longitudinally moving magnetic field of the stator as a so-called carriage or translator.
More information about linear motors and our drive solutions