What is the working principle of power tools?
An electric motor that rotates by alternating current is called an alternating current motor. There are many kinds, mainly:A, the series excitation motor - rectifier DC generator for AC motor, namely into this kind of motor, at the same time shift due to alternating current in the magnetic field and the armature circuit, therefore, the direction of the torque constant remains unchanged, the machine is kept turning. This kind of motor can also be used as AC and DC, so it is also called universal motor". Vacuum cleaner, sewing machine and other household appliances, etc..B, an induction motor -- a device that rotates the rotor in the rotating magnetic field and causes the rotor to rotate due to the action of eddy currents. Rotating magnetic field is not caused by mechanical method, but by alternating electric flux in the number of electromagnets, so that the magnetic properties of the cycle of change, can be seen as a rotating magnetic field. Usually three-phase induction motor (with three pairs of magnetic poles) is used. The motion of the DC motor is just the opposite of the direct current generator. In the generator, the induced current is formed by the induced electromotive force, so they are in the same direction. In an electric motor, the current is supplied by an external power supply, and the direction of the induced electromotive force is in opposition to the armature current I.C and synchronous motor - the motor with the armature from one pole to the second pole, just the same as the current that turns into the current. This kind of motor cannot start on its own and must be operated by another motor or special auxiliary winding so that the proper frequency can be reached before it can be switched on. If the load changes and the speed changes, the speed is not in line with the AC frequency, so that the pace of disturbance, tend to stop or cause damage. Due to restrictions, it is not widely used.
AC motor, AC motor of induction motor, its strong induction current (eddy current) magnetic field generated in the rotation of the magnetic force on the rotor copper bar, continuous cutting, according to Lenz's law, the induced current has the effect of relative motion occurs against the rotor magnetic field and the rotor is, with the magnetic field and rotation. But the rotor rotation speed of the high speed magnetic field does not transform, otherwise it will not be able to cut the copper lines.
A direct current motor called a direct current motor. Due to the magnetic field circuit and armature circuit of the different links, can be divided into series motor, motor, compound motor;
