How does the frequency converter change the voltage and change the speed of the motor?
In reducing the power frequency, the frequency converter must be reduced at the same time the power supply voltage, this is because, for the asynchronous motor, the phase voltage is proportional to the product of frequency and magnetic flux, when the frequency is reduced, if the voltage is constant, the flux will increase, it is easy to cause the magnetic saturation, excitation current surge, causing the motor to burn.The general frequency converter will automatically adjust the output voltage at the same time as the frequency is changed. What do you need to do without additional operation?.
The inverter does not change the voltage to adjust the speed of the motor. Under the premise of constant voltage, the frequency of the alternating current is changed to adjust the speed of the motor. Typically, at the frequency of 50Hz, the synchronous speed of the quadrupole motor is 1500 rpm, and if the frequency is increased to 60Hz, the synchronous speed should be 1800 rpm; if it falls to 40Hz, the synchronous speed should be 1200 rpm. In the limited frequency range, the power is constant, the higher the speed, the smaller the torque, the lower the speed, the greater the torque. Formula for speed calculation (Rev / min):60 seconds * / log polar frequency. The middle pole of a pair is 2 poles of 1 pairs, i.e., the quadrupole motor is 2 pairs of magnetic poles.The frequency of the converter is stepless, continuous and adjustable, so the speed of the motor is continuously adjustable in a certain range.
Change the motor frequency converter, V/F control mode in changing the motor frequency at the same time according to the proportion of changing the voltage of the motor, the speed and frequency of the motor is proportional to the relationship, so it changes the motor speed.
N = 60f/PN is the turn speed, F is the frequency, and P is the magnetic pole logarithm of the engineBy the formula: frequency and speed is proportional to, so the inverter can change the speed of the motor
The frequency converter regulates the speed of the motor, mainly by changing the frequency. The frequency determines the synchronous speed of the motor, and the speed of the motor can be lowered by reducing the frequency.
