Can V F ratio maintain constant for above base speed?

Can V F ratio maintain constant for above base speed?

V is kept constant above the base speed. Below the base speed (V/f) ratio is maintained constant, except at low frequencies where (V/f) ratio is increased to keep maximum torque constant.

Why is VF ratio kept constant up to base speed and V constant above base speed in variable frequency control?

Higher flux than its rated capacity leads to increased eddy current and hysteresis losses. The increased losses cause the heating of the core and as a result of this the insulation of core will get damaged. Therefore, when motor running through VFD the V/f ratio is kept constant.

How the induction motor speed can be increased above the rated speed?

Yes it is possible, For AC machines, this can be achieved by flux-weakning. As several people have already stated, it is possible to increase the speed of an ac motor by increasing the input frequency to the motor. This is done in industry by adding a variable frequency drive.

What is the V F?

V/F is abbreviated from voltage/frequency. V/F control is an induction motor control method which ensures the output voltage proportional with the frequency, so it maintains a constant motor flux, preventing weak magnetic and magnetic saturation phenomenon from happening.

What is V F ratio in VFD?

A V/f pattern defines a ratio of voltage-to-frequency for the motor to follow and a VFD can have only one V/f pattern programmed at a time. The V/f patter, or curve, determines what voltage is output to the motor based on a given speed reference (frequency).

What is V F method?

A control method that enables preventing reductions in the power factor or efficiency of a motor in a wide range of variable speed operation for changes in the frequency for speed control by outputting a voltage (V/f characteristic) corresponding to the frequency set by a parameter in an Inverter.

What is the rated v / f ratio for an induction motor?

I know it is used to control the speed, as the output is constant. However, for an induction motor I was doing an experiment on, the rated V/f ratio was 230V/50Hz with a rated speed of 1375rpm, whilst experimentally I got 254V/49.26Hz at a speed of 1480rpm.

Which is the best speed control for a three phase induction motor?

V/F SPEED CONTROL FOR THREE PHASE INDUCTION MOTOR. There are various methods which are used for the speed control of three phase induction motor such as stator voltage control, frequency control, rotor resistance control but v/f speed control is the most popular method which is used in adjustable speed drive system.

Is it possible to increase the voltage of an induction motor?

However, for an induction motor I was doing an experiment on, the rated V/f ratio was 230V/50Hz with a rated speed of 1375rpm, whilst experimentally I got 254V/49.26Hz at a speed of 1480rpm. I have read it is possible to get a motor speed greater than a rated speed by increasing the frequency.

Which is the fourth phase of a stud y induction motor?

The fourth stage represents the three – the IM). Last stage represents the three -phase squirrel c age IM. The IM used in the stud y is a three-phase 380V, 1.7 A, 0.55 kW, 50 Hz with 4 poles. 5. FPGA Based SPWM Control Scheme for VVVF Using V/F Control Strategy: