Electric motor, some of a class of devices that convert electricity to mechanical energy, usually by employing electromagnetic phenomena.
What is a power motor?
How can you bring things in motion and maintain them moving without moving a muscles? While steam engines create mechanical energy using scorching steam or, more precisely, steam pressure, electrical motors use electric energy as their resource. For this reason, electric motors are also known as electromechanical transducers.
The counter piece to the electric motor is the generator, which has a similar structure. Generators transform mechanic movement into electric power. The physical basis of both processes may be the electromagnetic induction. In a generator, current is certainly induced and electricity is created whenever a conductor is within a moving magnetic field. Meanwhile, within an electric motor a current-holding conductor induces magnetic fields. Their alternating forces of appeal and repulsion develop the basis for generating motion.
How does a power motor work?
Motor housing with stator
Motor housing with stator
Generally, the heart of a power motor consists of a 交流感应电机 stator and a rotor. The term “stator” comes from the Latin verb “stare” = “to stand still”. The stator is the immobile part of a power motor. It is firmly mounted on the equally immobile housing. The rotor on the contrary is mounted to the engine shaft and will move (rotate).
In case 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 usually flowing through the cables. This magnetic field produced by the stator induces a current in the rotor. This current then generates an electromagnetic field around the rotor. Because of this, 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 in order to drive a gear unit (as torque converter and speed variator) or to directly drive a credit card applicatoin as line motor.
What types of electric motors can be found?
All inventions began with the DC electric motor. Nowadays however, AC motors of various designs are the most commonly used electric motors in the market. They all have a common result: The rotary movement of the engine axis. The function of AC motors is based on the electromagnetic operating theory of the DC motor.
As with most electric motors, DC motors consist of an immobile component, the stator, and a moving component, the rotor. The stator consists either of an electric magnet used to induce the magnetic field, or of long lasting magnets that constantly generate a magnetic field. Within the stator is where in fact the rotor is usually located, also known as armature, that is wrapped by a coil. If the coil is linked to a source of direct current (a electric battery, accumulator, or DC voltage supply unit), it generates a magnetic field and the ferromagnetic core of the rotor turns into an electromagnet. The rotor is definitely movable installed via bearings and can rotate to ensure that it aligns with the attracting, i.electronic. opposing poles of the magnetic field – with the north pole of the armature opposing of the south pole of the stator, and the other way round.
In order to arranged the rotor in a continuing rotary movement, the magnetic alignment should be reversed again and again. This is achieved by changing the current path in the coil. The electric motor has a so-called commutator for this function. The two supply contacts are linked to the commutator and it assumes the duty of polarity reversal. The changing attraction and repulsion forces ensure that the armature/rotor proceeds to rotate.
DC motors are mainly utilized in applications with low power rankings. These include smaller equipment, hoists, elevators or electric vehicles.
Asynchronous AC motors
Instead of direct current, an AC motor requires three-phase alternating current. In asynchronous motors, the rotor is certainly a so-called squirrel cage rotor. Turning results from electromagnetic induction of this rotor. The stator consists of windings (coils) offset by 120° (triangular) for every phase of the three-stage current. When connected to the three-phase current, these coils each build-up a magnetic field which rotates in the rhythm of the temporally offset collection frequency. The electromagnetically induced rotor is definitely carried along by these magnetic areas and rotates. A commutator as with the DC engine is not needed in this way.
Asynchronous motors are also called induction motors, as they function just via the electromagnetically induced voltage. They run asynchronously because the circumferential acceleration of the electromagnetically induced rotor never reaches the rotational speed of the magnetic field (rotating field). Because of this slip, the efficiency of asynchronous AC motors is leaner than that of DC motors.
More on the structure of AC motors / asynchronous motors and on 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 slide at the same circumferential swiftness as that of the stator magnetic field. Efficiency, power density and the feasible speeds are thus significantly higher with synchronous motors than with asynchronous motors. However, the look of synchronous motors can be much more complex and time-consuming.
More details about synchronous motors and our portfolio
As well as the rotating machines that are mainly utilized in the industry, drives for motions on straight or curved tracks are also required. Such movement profiles occur mainly in machine tools along with positioning and handling systems.
Rotating electric motors can also convert their rotary motion into a linear motion using a gear unit, we.e. they are able to cause it indirectly. Frequently, however, they don’t have the necessary dynamics to realize particularly challenging and fast “translational” movements or positioning.
This is where linear motors come into play that generate the translational motion directly (direct drives). Their function can be produced from the rotating electrical motors. To get this done, imagine a rotating electric motor “opened up”: The previously circular stator becomes a flat travel distance (track or rail) which can be protected. The magnetic field then forms along this route. In the linear electric 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 series or in curves by the longitudinally moving magnetic field of the stator as a so-called carriage or translator.
More information regarding linear motors and our drive solutions