What distinguishes synchronous from asynchronous engine?

The motors come in two basic types — synchronous and asynchronous. What are those others? What distinguishes synchronous from asynchronous engine?

The content of the article

What is a synchronous motor?

To simultaneous considered motors that operate on alternating current and have a rotor with a rotational speed coinciding with the speed of the magnetic field in the design of the unit.

Key elements of a synchronous motor:

  • anchor;
  • inductor.
  • The first element of the Assembly is located on the stator. The inductor is placed on the rotor, which is separated from the stator by an air gap. The structure of the armature winding is represented by (one or more). Currents, which are served in an appropriate engine component, forming a magnetic field rotating at a predetermined frequency and interacting with the field of the inductor. 2 includes an inductor pole in a permanent magnet.

    Synchronous machine can operate in two modes:

    • actually the motor;
    • like a generator.

    The first mode of operation involves the interaction of the magnetic field formed on the armature, and the field, which is formed at the poles of the inductor. Synchronous motor in the generator mode operates by electromagnetic induction: in the process of rotation of the rotor magnetic field, which is formed by winding, in turn, interacts with the phase windings on the stator, which in turn causes an electromotive force.

    to table of contents ↑What is a induction motor?

    By asynchronous , it is customary to include electric motors in which the rotational speed of one of the key elements of the rotor does not coincide with the rotational speed of the magnetic field formed by the current that occurs in the stator winding. Asynchronous aggregations sometimes referred to as induction. This is due to the fact that the rotor winding is induced by current when exposed to a magnetic field of the stator.

    In the design of an induction motor are a stator and a rotor separated by an air gap. The main active components of the machine:

    • winding;
    • a magnetic core.

    Important role in the functioning of the asynchronous motor are additional structural elements that provide strength, cooling, and stability of operation of the unit.

    to table of contents ↑the Difference between synchronous and asynchronous motor

    The main difference between synchronous motor and asynchronous is the ratio of the magnitude of frequency of rotation of the rotor and the magnetic field. The unit of the first type both indicators are the same. In the asynchronous machine different.

    It can be noted that the motors of the second type is generally more prevalent than the first. While the asynchronous units is often presented in varieties, which has installed a squirrel-cage rotor. These devices have several important advantages over electric motors and other categories. Namely:

  • simplicity of design, reliability;
  • the relatively low cost of production and operation;
  • the ability to operate through the activation of existing network resources without connecting transducers.
  • However, asynchronous machines squirrel-cage motors have certain drawbacks. Namely:

    • the presence of small starting torque;
    • the presence of a large inrush current;
    • low power factor;
    • low controllability from the point of view of speed regulation;
    • the dependence of the maximum speed from the frequency of the electrical network;
    • electromagnetic torque in induction motors of the type under consideration is characterized by strong sensitivity to the voltage drop in the network.

    In turn, the synchronous units also have undeniable merits. These include:

    • relatively low sensitivity to voltage drops in the network;
    • stability of rotation irrespective of the load on the rotor.

    Have synchronous motors and disadvantages:

    • the relative complexity of the design;
    • the complexity of the run of the rotor.

    These features of the synchronous and asynchronous units make optimum use of the first case, if the required engine power in the system (for example, as part of the infrastructure of the factory line) should be of the order of 100 kW or more. In other cases, the involvement of asynchronous machines, as a rule, is more preferable.

    Examined the difference between synchronous and asynchronous motor, reflect the findings in the table.

    to content ↑Comparative table

    Synchronous motor
    Asynchronous motor

    The rotation of the rotor and the magnetic field in a synchronous motor is carried out with the same frequency
    The rotation of the rotor and the magnetic field in the asynchronous units is carried out with different frequency

    Is often more complex in design
    Usually has a less complex design

    Optimal if the required capacity 100 kW and above
    Optimal if the required capacity of less than 100 kW

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