# What is a three phase connection?

What is a three phase connection?

RYB, 440 volt/phase

## Related questions

Description : Explain MCB and ELCB with connection diagram supplying single phase load.

Answer : OR OR Explanation: * MCB provides short circuit protection. * MCB provides overload protection * ELCB provides earth fault protection. * MCB is in series with ... occurs, the ELCB cuts off the power within the time of 0.1 sec. automatically to protect the personnel.

Description : Write the relation between phase and line current, phase and line voltage for Star connection.

Answer : Line voltage is equal to root three times of phase voltage and line and phase currents are equal in star connection

Description :

What is mean by plugging in three phase induction motor?

Answer : Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.

Description : What is difference between Star and Delta Connection?

Answer : Star is        1. Open ckt       2. At center point present  neutral   Delta is     1.   Closed ckt 2.      Neutral not present in this case

Description : List different starting methods of three phase synchronous motor. Explain any one of them.

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 : Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.

Description : Explain the need and steps to conduct the reduced voltage running up test on the three phase induction motor.

Description : Why is a capacitor used in a single phase motor and not in three phase motor ?

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 ?

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.

Description : Define balanced and unbalanced load in three phase circuit.

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.

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 : Draw the waveform of three phase AC supply voltage.

Description : State advantages of three phase over single phase.

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

Answer : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent

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%

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?

Answer : In a three-phase supply floating neutral is undesirable because it way give rise to unequal line voltages across the load.

Description :

Three phase synchronous motor will have how many sliprings?

Answer : Three phase synchronous motor will have two sliprings.

Description :

How is a three phase cage induction motor self starting?

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 power relations in three phase circuit.

Description : Explain three phase half wave controller or three phase unidirectional controller.

Answer : Three phase half wave controller or unidirectional controller:

Description : Explain Three Phase Bidirectional Delta Connected Controller.

Answer : Three Phase Bidirectional Delta Connected Controller:

Description : Explain three phase bridge inverter.

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.

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 : three phase to single phase cycloconverter

Answer : three phase to single phase cycloconverter

Description : how can we reverse the direction of rotation of three phase induction motor ?

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.

Description : Explain with the neat circuit diagram only the scott connection scheme for conversion of three phase supply to two phase supply. Name one application of the same.

Answer : Three-phase to Two-phase Transformation (Scott Connection of Transformers): Working: i) Scott connection can be used for three-phase to two-phase conversion using two single-phase transformers ... a 3-phase system with a two-phase system with the flow of power in either direction.

Description : Write short notes on 3 phase AC system.

Description : Which of the following 3-phase connection of a transformer causes interference with the neighbouring communication lines:  (A) Delta-Star (B) Star-Delta (C) Delta-Delta (D) Star-Star

Answer : Which of the following 3-phase connection of a transformer causes interference with the neighbouring communication lines: Star-Star

Description : What is the voltage in 3 phase line?

Answer : between 430 to 440 v

Description : State the principle of solar cell. What is necessity of series and parallel connection of solar cells.

Answer : Principle of solar cell:-  Working:- Solar cell operates on principle of Photo-voltaic effect Solar cell works in following steps:  The solar cell is composed of a P-type ... of Voltage & Current rating it is necessity of connecting series and parallel connection of solar cells.

Description : number of windings of a coil in a stator of ac motor for ey slot ac motor

Description :

State functions of ; i) Cable box ii) Guard wire iii) Shackle insulator iv) Stay wire used in service connection

Answer : i) Function of Cable box: To hold and inspect incoming and outgoing terminals  ii) Function of Guard wire : A grounded conductor placed beneath an overhead transmission line in order to ground ... in service connection: To give mechanical Support to pole, line and prevent leakage current if any

Description : Why underground service connections are service connections are costly than overhead service connection

Answer : Reason: Underground service connection is given by underground cable. This cable is costly than bare conductor. Sometimes cable trench is required for cable laying, which requires additional cost. So underground service connections are costly than overhead service connection.

Description : Define service connection and state types connection and state types of overhead service connection

Answer : Service Connection:- It is the input conductor or wire which is carried out from supply company (authorities) pole to consumers' main board or premises. Types of overhead service ...  1. Overhead service connection with Bare conductor 2. Overhead service connection with weather proof cable

Description : State necessity of series connection and parallel connection of batteries.

Answer : Necessity of series connection of batteries: 1. The batteries are available with some specific terminal voltages. e. g. 6V, 12V, 24V, 48V etc. 2. If we want to have some terminal voltage other than ... batteries of capacities I1, I2, I3, I4 . are connected in parallel, all having identical emfs.

Description : Compare star and Delta Connection.

Answer : Compare Star and Delta connected system:  Star connected system Delta connected system   In STAR connection, the starting or finishing ends (Similar ends) of three coils are connected together to form the ... VPH Line Current is √3 times of Phase Current. i.e. IL = √3 IPH

Description : Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

Answer : Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

Description :

Answer : Direction of rotation of a split phase motor can be reversed by reversing the connection of either running winding or starting winding.

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

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 : What are three ways you can increase the strength of an electromagnet?

Description : what is the difference between four point starter and three point starter?

Answer : The only difference is in the NO VOLT COIL connection in the starter, in three point starter NVC is connected to the field whereas in four point starter it is connected separately. The advantage of using ... (for above rated speed) and lead to DEENERGISE the NVC leading to turning off of the motor.

Description : For a balanced three phase star connected load for which line voltage is 230V and per phase resistance and reactance is 6 Ohm and 8 Ohm respectively. Calculate: 1) phase voltage 2) line current 3) power factor 4) total power absorbed

Description : Define phase sequence of three phase supply with waveforms. What is normal phase sequence? Which 3 standard colours are used to denote the phase sequence?

Answer : It  is  sunnosoidal  sequence.

Description :

Answer : In case one phase of a three-phase synchronous motor is short-circuited the motor will not start.

Description : speed control methods of three phase induction motor?

Answer : Speed control of three phase induction motor

Description : List three important characteristics of an electric circuit.

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

Answer : When three resistors with unequal values are connected in parallel, The voltage drop across the resistors is the same

Description :

Answer : Three point starter can be used for both shunt and compound motor.

Description :

Answer : A three point starter is considered suitable for shunt as well as compound motors.

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