Why stator Voltage Control is inefficient?
Stator Voltage Control is a method used to control the speed of an Induction Motor. … Hence, to reduce the speed for the same value of the same current, the value of the voltage is reduced and as a result, the torque developed by the motor is reduced.
What are the advantages of voltage frequency control?
Benefits or advantages of variable frequency drive:
- It is better to process control.
- VFD is of greater efficiency.
- It is a smooth start and stops.
- It is noise reduction.
- It is reduced motor heating.
- VFD has less cost.
- It controls speed.
- It reduced harmonics.
What is the application where stator Voltage Control method for speed control of induction motor is suitable?
Therefore, the stator voltage control method is suitable for applications where the load torque decreases with the speed, as in the case of a fan load. By the stator voltage control method, the speed of the motor can be varied within a small range.
Which of the following is the disadvantages of rotor resistance control?
The major disadvantage of the rotor resistance control method is that the efficiency is low because of the additional losses present in the resistors connected within the rotor circuit. The efficiency is greatly reduced at low speeds because of the higher value of the slip.
What is VFD and its advantages and disadvantages?
Advantages of a Variable Frequency Drives – The main reason/advantage for implementing a VFD into a system is to save money by reducing the overall system energy being consumed. … Disadvantages of Variable Frequency Drives – VFD’s, though useful in making a system more efficient also bring with them some disadvantages.
What are the disadvantages of DC drives?
Disadvantages of DC motors
- High initial cost.
- Increased operation and maintenance cost due to the presence of commutator and brush gear.
- Cannot operate in explosive and hazard conditions due to sparking occur at brush (risk in commutation failure)
What is the function of a stator?
The stator is the coil of wire housed inside the engine case. A magnet on a shaft spins within the stator, creating alternating current (AC). That current travels along fairly heavy gauge wire through the case and into the rectifier/regulator which converts it to DC power, and at a consistent output.
What is stator current control?
Constant stator current control for three-phase induction motor drive with fixed exciting current. … And one of windings of induction motor is used to detect air gap flux, it corrects stator current to achieve fixed exciting current.
Which one of the following methods of speed control Cannot be applied for controlling the speed of a three phase squirrel cage induction motor?
The rotor connections are not brought out at the outside, it is short-circuited inside of the motor. So that it is not possible to connect external resistances to rotor conductors, thus we don’t have control over the speed of induction motor in squirrel cage type.
How is the speed of a 3 phase induction motor controlled by its stator voltage control?
Induction motors are constant speed motors, hence if we desire to use these motors for variable speed applications, the speed can be vary by using AC power controllers. As the torque is directly proportional to the square of the voltage, the torque can be varied with stator voltage, so, in turn, the speed.