What is the effect of unbalanced the voltage on the operation of the induction motor?
A small amount of voltage unbalance may increase the current an excessive amount. The effect on the motor can be severe and the motor may overheat to the point of burnout.
Why is an induction motor very sensitive to unbalance in supply voltage?
Large induction motor is very sensitive to unbalance in supply voltage. The negative sequence component, which comes into picture because of the unbalance in the supply, is particularly troublesome. This is because the motor offers very small impedance to the negative sequence currents.
When an unbalanced supply given to an induction motor it will cause effect on?
Unbalanced 3-phase voltage supply to an induction motor causes excessive heating of. (a) rotor.
Which of the following is an adverse effect of voltage unbalance in case of an induction motor?
The effects of voltage unbalance on the motor such as, unbalanced currents, temperature rise, increased losses, output power and torque reduction, pulsation torques and speed reduction, has been studied by several authors,  – .
What are the effects of unbalanced voltage?
Voltage unbalances will cause extra power loss, reduce system efficiency, reduce motor life cycle, etc. Also some abnormal functioning and maintenance conditions also cause voltage imbalance and result in negative impacts on equipment and systems.
What negative effects can unbalanced three-phase line voltages have on the operation of a motor?
Vibration of Motor: The negative-sequence voltage caused by voltage imbalance produces opposite torque and leads to motor vibration and noise. Severe voltage imbalance may even result in motor collapse. Reduce Motor Life: Heat generated by Unbalance Voltage may also reduce the Motor life.
Why do motors have an unbalanced current?
Causes of unbalance
– With continuous operation, motor’s physical environment cause degradation of rotor and stator windings. This degradation is usually different in different phases, affecting both, the magnitude and phase angel of current waveform.
When an unbalanced supply given to an induction motor it will cause effect on MCQ?
Explanation: Unbalanced supply will cause most heating of rotor winding than any other part. Explanation: All the possibilities can happen if one of the phase is removed. 7.
What is unbalance voltage?
Voltage unbalance occurs when the RMS line voltages on a poly-phase system are unequal. Voltages are seldom perfectly balanced between phases, but when this unbalance becomes excessive, it can create problems for poly-phase motors.
What is the maximum voltage unbalance of a 3 phase motor?
Voltage unbalance exceeding more than 2 percent in three-phase systems can cause current unbalance among the windings. These, in turn, can cause an increase in winding temperature and an overheating problem that can be harmful to the motor.
On what factors does the speed of an induction motor depends?
From the above expression, the speed of an induction motor is depends upon the the supply frequency and the number of poles.
What is special about reluctance motor?
The rotor does not have any windings. It generates torque through magnetic reluctance. Reluctance motor subtypes include synchronous, variable, switched and variable stepping. Reluctance motors can deliver high power density at low cost, making them attractive for many applications.
What are the adverse effect of unbalanced current in three-phase transformer?
The long-term running with three- phase unbalance of the distribution system shall lead to a series of problems, such as increase of transformer loss, reduction of output of the transformer, reduction of the active output of the motor, increase of loss of the distribution line, damage of electric equipment of the user, …
What is the effect of unbalanced load in three-phase system?
In most cases an unbalanced loading of the three phases causes voltage imbalance. These could be single or two phase loads that are not equally split over all phases, for example boilers, heaters, air conditioning, welding and single phase power supplies for computers or servers etc.
What causes phase unbalance?
A phase unbalance may be caused by unstable utility supply, unbalanced transformer bank, unevenly distributed single-phase loads on the same power system, or unidentified single-phase to ground faults.