The type of speed adjustment of ac motor and the difference between them
Variable frequency adjustable speed -- -- -- -- - this is by far the most common way of speed regulation, can achieve stepless speed regulation, after semiconductor converter circuit (or) change the frequency of the motor power supply, the mains frequency (= 50 hz) change as needed to achieve the purpose of speed regulation, frequency or the above formula: ac motor synchronous speed = 60 f/pole logarithm, th
Speed regulating pole change motor -- -- -- -- -- - a specific motor internal to do particular winding, by motor different connection mode change polarity logarithm, get a different speed. Formula: the synchronous speed of ac motor is 60f/magnetic poles (f - - frequency), the magnetic poles are changed and the rotational speed is changed. The drawback is that it cannot be stepless speed adjustment (such as 2-4 pole motor, synchronous speed only two gears, the two poles are 3000, and then the 4 pole is 1500.
There are three types of ac motor speeds common in industry. 1, the slip motor speed -- -- -- -- -- - on the motor output shaft is equipped with a pair of electromagnetic coupling, speed tests to adjust the magnetic field of the coupling with a set of speed. (not very much now, the disadvantage is inefficiency, the advantage is that it can be adjusted without speed.)
