Rotor Motors in Short Circuit

The shorted rotor name is given because of the type of rotor used, which is considered the most common in the industry. Some basic particulars need to be understood when it comes to electrical commands. Generally, the squirrel cage-type rotor induction motor consists of two parts, by the stator, which is the electric motor magnetic circuit, generally of the grooved type, in which are installed the coils which with the proper connection, generate the rotating magnetic field. The rotor has a winding formed by copper or aluminum bars short-circuited at the ends. The current in the rotor circuit is induced by the action of the rotating field of the stator.

In this way, the induction motor in operation means that the magnetic field made in the rotor circuit will chase the rotating field of the stator. In the case of the motor being energized, it works as a transformer with the secondary one in short circuit, requiring from the electrical network a current greater than nominal, reaching up to eight times its value. High starting currents cause unpleasant situations, requiring cable sizes with larger diameters than expected.




The Three Phase Induction Motor

Electric motors act from the moment the electric current produces a magnetic field, in which when it varies in relation to a conductor, it causes an electric current. The rotor current causes a magnetic field that must oppose the motion that generated the poles opposite to that of the stator. The result is that the stator field impels the rotor at the moment of rotation, but always at a higher speed, causing the rotor to slip relative to the rotating field.    5600 OMP

When a load is placed on the motor shaft, the rotor slows down, increasing slipping. Generally, two magnets are formed, one in the stator and the other in the rotor, in which, their interaction causes the movement of the motor. In the three-phase induction electric motor, the distribution of the coils of the three phases in the stator, are lagged at 120º, and ends up making the sum of the magnetic fields generated by each of them a uniform and rotating field. This field circulates in the magnetic stator and rotor cores, and generates a current flow in the rotor bars.




Starting Speed

In DC electric motors, the speed can be adjusted by inserting a rheostat into the field circuit to ensure flow adjustments. The connection of the motors to a public power grid must comply with the regulations established for this purpose.

Generally we try to start a motor at full voltage, so that you can make the most of the starting torque and another way to adjust the speed of AC motors, which can allow the acquisition of the speed axis, which can range from zero to twice the synchronous speed, is by the well-known rotor system with a switch, by means of brush off.    2BK80H

The possibility that exists when we deal with the change of speed in electric induction motors is achieved through the frequency inverter, which allows the control of the alternating current motor, thus changing the frequency, as well as making the change of the output voltage, in order to respect the characteristic of the V / F motor, which is the motor frequency voltage.





Electric Motors – How to Transport

When dealing with the handling process of any type of electric motor, any transport that is necessary should be done in a subtle way, avoiding any collision, otherwise the bearings in them, may suffer a failure, just as if the eyes are subjected to excessive stresses and may result in the breakage of these eyes. If it is necessary to carry the motor in the horizontal position, the axle locking device must be used on the front and rear sides of the motor.   BOSTON 06970 9F 1-3

In electric motors there are several devices whose main function is to ensure that they function dynamically. The devices responsible for axle locking, which are generally used for protection during the transport process in the case of motors having roller bearings or angular contact, must be used for any and all locomotion of the engine, even if this factor requires the separation of the machine triggered. All engines with these features, regardless of the type of bearing, should always keep your rotor locked at the time of transportation. Vertical motors containing oil lubricated bearings also need to be transported vertically.


Energy and Mechanical Power

Even if the energy is only one, it is possible to be achieved in different ways, that is, if a resistance is connected to an electric grid with voltage, an electric current can pass that can heat the resistance, in turn, the resistance will be able to absorb energy and turn it into heat, which will also be a form of energy. An electric motor absorbs electrical power from the grid and turns it into available mechanical energy at the tip of the shaft. CA38112 M

The power is to measure the speed at which the energy is consumed or applied, so the energy expended or the effort made to bring a bucket from the bottom of a well to the surface is always the same, power will reflect the speed that this energy is applied to raise the bucket, however, the power is nothing more than the total energy realized divided by the total time for it to be produced. The unit used for mechanical power is Watt (W), however, the unit most commonly used for mechanical power is c.v., also known as horsepower, which is equivalent to 736W.