The rated speed of ac motor
The alternating current of the ac motor = 60f/p.f is the frequency of alternating current. P is the magnetic pole. 60 is a minute. Four pole motor is 2 to the poles. So the theory of a quadrupole motor number is 1500 r/min. This is a rotating magnetic field of revolution. Actual revolutions is lower than a rotating magnetic field of revolution. Quadrupole motor is generally 1450 revolutions per minute
The rotation principle of the three-phase asynchronous motor Three-phase asynchronous motor to spin the prerequisite is to have a rotating magnetic field, three-phase asynchronous motor stator winding is used to produce a rotating magnetic field. We know that, but the phase of phase to phase voltage is in phase difference of 120 degrees, three of the three-phase asynchronous motor stator winding on the spatial orientation also sent 120 degrees, so, when during a stator winding into the three-phase power supply, the stator windings creates a rotating magnetic field, current every change is a cycle, a rotating magnetic field in a week, i.e., the change of the rotation of the rotating magnetic field and electric current is synchronized. The rotational speed of the rotating field is: n = 60f/P, f is the power frequency, P is the magnetic pole of the magnetic field, and the unit of n is: revolutions per minute. According to this formula, the speed of the motor is related to the number of poles and the frequency of the power supply. In general, the actual rotational speed of the motor lags the rotation of the magnetic field. For this we call the three-phase motor as the asynchronous motor.
It is impossible to achieve 1500 RPM if there is no mechanical loss in itself, such as bearing friction, etc
Synchronous speed of motor is 60 * frequency/magnetic log 8 extreme: 60 * 50/4 = 750 RPM, and asynchronous RPM is slightly reduced by about 735 RPM 6 extreme: 60 * 50/3 = 1000 RPM/min, the asynchronous RPM is slightly reduced by about 980 RPM Extreme: 60 * 50/2 = 1500 RPM, and asynchronous RPM is slightly reduced by around 1475 RPM Extreme: 60 * 50/1 = 3, 000 RPM, and the asynchronous speed is slightly reduced by about 2970 RPM "Ac motor" is a machine used to realize mechanical energy and exchange electrical energy. Ac motor has become the most commonly used electric motor due to the huge development of ac power system. Compared to the ac motor and dc motor, with no commutator (see dc motor commutator), so the simple structure, easy fabrication, quite strong, easy to make a high speed, high voltage, high current, the large capacity motor. Ac motor power covers a wide range, ranging from a few watts to several hundred thousand kilowatts and even a million kilowatts. In the early 1980s, the largest turbine generator was 1.5 million kilowatts.
