Description : THREE PHASE INDUCTION MOTORS MCQ
Last Answer : 101. Insertion of resistance in the stator of an induction motor (a) increases the load torque (b) decreases the starting torque (c) increases the starting torque (d) none of the above Ans: b
Description : List different starting methods of three phase synchronous motor. Explain any one of them.
Last Answer : Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor.
Description : Why is a capacitor used in a single phase motor and not in three phase motor ?
Last Answer : In 1-phase induction motor capacitor work is generate the auxiliary winding current than excite the main winding to rotor starts rotate. After rotor start rotating about 75% of their speed than auxiliary ... emf to start the motor.so,in 3-phase induction motor is self start induction motor.
Description : Why is a three phase denoted by R, Y, B ?
Last Answer : phase 1 ,R =Red colour cable terminal, phase 2 Y=Yellow colour terminal cable,Phase 3 B=Blue colour cable terminal, N =Neutral. For identification.
Description : State any four advantages of three phase induction motor.
Last Answer : Advantages of three phase induction motor https://youtu.be/27OIOCKN05U
Description : Define balanced and unbalanced load in three phase circuit.
Last Answer : Balanced Load: When all the imedances of 3 phases are equal in magnitude and of same nature then load is said to be balanced. Unbalanced Load: When all the imedances of 3 phases are not equal in magnitude and of different nature then load is said to be unbalanced.
Description : State any four applications of three phase circuits.
Last Answer : The application of three phase circuits are 1. Three phase circuit is used for power transmission over long distances. 2. Three phase circuit can produce rotating magnetic field 3. Three phase ... three phase Motors and Transformers. 4. Three phase circuit is used for power converters circuits.
Description : State advantages of three phase over single phase.
Last Answer : Advantages of 3-phase system over 1-phase system: - 1. More output: For the same size, output of poly-phase machines is always higher than single phase machines. 2. Smaller size: For ... are self- starting: The three phase ac motors are self starting, while single phase induction motor are not.
Description : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is
Last Answer : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent
Description : Consider a circuit with three parallel branches connected across a DC supply. What is the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio of 2 : 3 : 4 respectively? A) 2 : 3 : 4 B) 6 : 4 : 3 C) 4 : 3 : 2 D) None of these
Last Answer : Consider a circuit with three parallel branches connected across a DC supply. What is the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio of 2 : 3 : 4 respectively? A) 2 : 3 : 4 B) 6 : 4 : 3 C) 4 : 3 : 2 D) None of these
Description : When three resistors with unequal values are connected in parallel, _______ A) The current across the resistors is the same B) The voltage drop across the resistors is the same C) The voltage drops across the resistors is proportional to the resistance of each resistor D) None of these
Last Answer : When three resistors with unequal values are connected in parallel, The voltage drop across the resistors is the same
Description : When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is (A) 86.6% (B) 50% (C) 57.7% (D) 73.2%
Last Answer : When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is 73.2%
Description : In a three-phase supply floating neutral is undesirable because it way give rise to?
Last Answer : In a three-phase supply floating neutral is undesirable because it way give rise to unequal line voltages across the load.
Last Answer : Three point starter can be used for both shunt and compound motor.
Last Answer : A three point starter is considered suitable for shunt as well as compound motors.
Description : Three phase synchronous motor will have how many sliprings?
Last Answer : Three phase synchronous motor will have two sliprings.
Description : How is a three phase cage induction motor self starting?
Last Answer : Any type of induction motor is self starting. Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if ... torqe also pulsating. In induction motor this angle theta is not pulsating.so it is self starting
Description : Explain three phase half wave controller or three phase unidirectional controller.
Last Answer : Three phase half wave controller or unidirectional controller:
Description : Explain Three Phase Bidirectional Delta Connected Controller.
Last Answer : Three Phase Bidirectional Delta Connected Controller:
Description : What is mean by plugging in three phase induction motor?
Last Answer : Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.
Description : Explain three phase bridge inverter.
Last Answer : Three phase bridge inverter: Three phase bridge inverter converts DC voltage input to three-phase variable frequency variable voltage output. DC voltage source can be a DC source or output of the rectifier. ... in proper sequence. The switch may be thyristor or IGBT etc.
Description : Explain three phase full wave controller.
Last Answer : Three phase full wave controller: Three phase full wave controller is also called as the three-phase bidirectional controller. Let the load is star connected so at each phase there are antiparallel connected SCRs. ... conduct at the same time and the third phase will be open.
Description : What is a three phase connection?
Last Answer : RYB, 440 volt/phase
Description : what is the difference between four point starter and three point starter?
Last Answer : The shunt connection in four point starter is provided separately form the line where as in three point starter it is connected with line which is the drawback in three point starter.
Description : three phase to single phase cycloconverter
Last Answer : three phase to single phase cycloconverter
Description : how can we reverse the direction of rotation of three phase induction motor ?
Last Answer : The direction of rotation of three phase induction motor can be reversed by plugging i.e by changing any two out of three phases of the supply to the stator of the Induction motor terminal.