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What happens if the frequency is increased by keeping the voltage constant in speed control of induction motor?
Constant V/F control of induction motor This will cause excessive stator current and distortion of the stator flux wave. Hence, if the ratio of voltage to frequency is kept constant, the flux remains constant. Also, by keeping V/F constant, the developed torque remains approximately constant.
How can we increase the speed of induction motor?
Speed Control of Three Phase Induction Motor
- V / f control or frequency control.
- Changing the number of stator poles.
- Controlling supply voltage.
- Adding rheostat in the stator circuit.
How does frequency affect current?
In an inductive circuit, when frequency increases, the circuit current decreases and vice versa.
Can a 50Hz motor run at 60Hz?
Electrical machines designed for 50Hz can usually work safely in 60Hz power supply, but not applicable to 60Hz machines to be run in 50Hz power supply.
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.
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.
What happens when you increase the frequency of a motor?
For many motors, you can continue to increase frequency above rated frequency, but you should not increase the voltage. Increasing frequency will cause the motor to spin faster, but, if the voltage is held constant, the available torque will decline as frequency increases.
How is the torque speed of an induction motor determined?
When the inverter output voltage at each inverter output frequency is controlled so that the V /Hz ratio is kept constant up to the rated speed, a family of torque-speed curves can be derived similar to Fig. 7.24. Fig. 7.24. VFD Supplied induction motor torque-speed curve with voltage and frequency variation and constant V /Hz ratio.