Types of AC motor speed control and the difference between them
Frequency conversion speed, which is currently the most commonly used control methods, can achieve stepless speed regulation, the semiconductor converter (or circuit) to change the power supply frequency of the motor, the power (frequency =50HZ) change into the required frequency achieve the purpose of speed, or the above formula: =60f/ magnetic pole synchronous AC motor speed. The frequency of "F", the speed will change.
Motor variable pole speed regulation ---- a specific motor internal to do a specific winding, through the motor of different wiring mode to change the motor magnetic pole logarithm, get different speed. Formula: synchronous motor speed, =60f/, magnetic pole logarithm (f--- frequency), magnetic pole logarithm change, the speed also changed. The disadvantage is not stepless speed regulation (such as 2-4 pole motor, synchronous speed is only two gear, when connected to the 2 pole is 3000 rpm, when connected to the 4 pole, is 1500 rpm.
Slip motor speed regulation ---- the motor output shaft is equipped with a pair of electromagnetic coupling, through the speed detection to adjust the magnetic field of the coupler, so that it has set speed. (it is no longer seen, the drawback is that the efficiency is low, the advantage is that stepless speed regulation)
