Which of the following 3-phase connection of a transformer causes interference with the neighbouring communication lines: Star-Star
Last Answer : The inductive interference between power and communication line can be minimized by transposition of the power line, transposition of the communication line.
Description : Explain MCB and ELCB with connection diagram supplying single phase load.
Last 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 : 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.
Last 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 the relation between phase and line current, phase and line voltage for Star connection.
Last 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 a three phase connection?
Last Answer : RYB, 440 volt/phase
Description : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is :
Last Answer : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is : 200 V
Description : Two 3-phase transformers cannot be operated in parallel, if their : (A) kVAs are different (B) phase sequences are different (C) % impedances are different (D) voltage ratios are different
Last Answer : Two 3-phase transformers cannot be operated in parallel, if their : phase sequences are different
Description : State the principle of solar cell. What is necessity of series and parallel connection of solar cells.
Last 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 : State necessity of series connection and parallel connection of batteries.
Last 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 : 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
Last 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 : How can I get rid of humming from AUX cable?
Last Answer : answer:You're picking up some combo of 60 Hz AC hum and RFI (radio frequency interference) making its way into the amplifier electronics. Try some of the following: (1) reduce the cable length. Shorter ... are probably not going to work either, & might make things much worse. Hope any of this helps.
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?
Last Answer : It is sunnosoidal sequence.
Description : Damper winding is provided in 3 phase synchronous motors to :
Last Answer : Damper winding is provided in 3 phase synchronous motors to : provide starting torque and prevent hunting
Description : The direction of rotation of an inverter fed 3-phase ac motor is reversed by (A) a mechanical reversing switch (B) reversing the input dc link voltage (C) operating the inverter as a rectifier (D) changing the sequence of switching
Last Answer : The direction of rotation of an inverter fed 3-phase ac motor is reversed by changing the sequence of switching
Description : The sequence components of current of a single-phase load connected to a 3-phase system are (A) equal positive and negative sequence components (B) equal positive, negative and zero sequence components (C) vector sum of sequence currents is zero (D) algebraic sum of sequence currents is zero
Last Answer : The sequence components of current of a single-phase load connected to a 3-phase system are equal positive, negative and zero sequence components
Description : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm
Last Answer : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min 200 rpm
Description : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in (A) voltage notching (B) harmonic distortion (C) voltage sag (D) voltage swell
Last Answer : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in voltage notching
Last Answer : In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at 120°.
Last Answer : A balanced 3-phase system consists of positive sequence currents.
Description : UPS- How to give Connection?
Last Answer : Ans. Means Uninterrupted power supply. To give UPS connection, first normal supply is kept off. Then, loads of essential and non essential are to be segregated. Essential loads are to be brought under single point of control. Then, UPS can be connected.
Description : State functions of ; i) Cable box ii) Guard wire iii) Shackle insulator iv) Stay wire used in service connection
Last 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
Last 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
Last 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 : Compare star and Delta Connection.
Last 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 : What is difference between Star and Delta Connection?
Last 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 : What will happen if transformer in parallel connection have different phase sequence ?
Last Answer : If the phase sequence is in an incorrect manner, in every cycle each pair of phases will get short-circuited.
Description : How different are people really?
Last Answer : On a universal level we are all one, as we are one with every organism, all created “equal” in natures grand design. On a “personal” level we are vastly different in how our nature/nurture/cultural dichotomies show up. Sooo…the usual double edged sword.
Description : Do you find yourself feeling a special bond with certain others on Fluther?
Last Answer : Definitely although I hate to be cliquey. There are some who you just have an affinity for and an ease with. and those with superior intelligence who agree with me
Description : How do I open gaming ports on my Belkin router?
Last Answer : is there a thing called DMZ on the website. under a tab named application & gaming?
Description : 72 Harmonics in transformer result in A. Increased core losses B. Increased I2R losses C. Magnetic interference with communication circuits D. All of the above
Last Answer : D. All of the above
Description : The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : (A) 34.64 kVA (B) 75 kVA (C) 20 kVA (D) None of the above
Last Answer : The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : 34.64 kVA
Description : A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is (A) 216 V (B) 226 V (C) 234 V (D) 236 V
Last Answer : A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is 226 V
Description : Which type of connection is used in distribution transformer?
Last Answer : Distribution transformers are connected in delta-star. This arrangement requires 3 conductors in the high voltage side and 4 in the low voltage side, as well as it provides the star point conductor as a neutral point. This can serve single phase as well as three phase loads.
Description : What will happen if transformer in parallel connection have different percentage impedance or X/R ratio ?
Last Answer : A difference in the ratio of the reactance value to resistance value of the per unit impedance results in a different phase angle of the currents carried by the two paralleled transformers; one ... of the combined output. Hence, the real power will not be proportionally shared by the transformers.
Description : What will happen if transformer in parallel connection have different voltage ratio?
Last Answer : Two transformers in Parallel should have the same primary and secondary voltage ratings. Any error in the voltage ratio would cause heavy circulating currents to flow between the transformers. ... in overloading of one transformer. This circulating current will result in increased copper losses.
Description : What will happen if transformer in parallel connection have opposite polarity?
Last Answer : Connecting transformers with wrong polarity can result in circulating currents or short circuits
Description : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?
Last Answer : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ? Δ-Δ connection
Last Answer : Transformer noise is generated due to vibration of core and winding this is because of magnetostriction and magnetomotive force.
Description : What is the supply rated o/p if two single phase transformer connect to give three phase o/p from a three phase I/p?
Last Answer : A. Each transformer is only capable of supplying 86.6%of its o/p rating
Description : How to connect two single phase transformer to give three phase o/p from a three phase I/p ?
Last Answer : A. They would have to connect in an open-delta.
Description : Can a Single Phase Transformer be used on a Three Phase source?
Last Answer : A. Any single phase transformer can be used on a three phase source by connecting the primary leads to any two wires of a three phase system, regardless of whether the source is three phase 3-wire or three phase 4 wire. The transformer output will be single phase.
Description : What are the various types of three phase transformer connections?
Last Answer : The most common types of transformer connections are, i. Star-Star (Y-Y) ii. Delta-Delta(∆-∆) iii. Star-Delta (Y-∆) iv. Delta-Star (∆-Y) v. Open Delta (V-V) vi. Scott Connection (T-T)
Description : What are the advantages of three phase transformer over three single phase transformer?
Last Answer : 1.Saving in iron material 2. Small size 3. Less transformer oil 4. Economical 5. Higher efficiency
Description : What are the advantages of three single phase transformer over three phase transformer?
Last Answer : 1. Continuity of supply 2. Less Installation of cost 3. Easy transportation 4.Stand by function 5.Unbalanced load supply
Description : What is single and three phase transformer?
Last Answer : The transformer which works on single phase is called single phase transformer. The transformer which works on three phase is called three phase transformer.
Description : 6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary
Last Answer : C. In phase with each other
Last Answer : Yes. Any single phase transformer can be used on a three phase source by connecting the primary leads to any two wires of a three phase system, regardless of whether the source is three phase 3-wire or three phase 4-wire. The transformer output will be single phase.
Description : Single phase transformer
Last Answer : Single phase Transformer Transformer
Description : Explain construction and working of single phase Auto transformer.
Last Answer : Construction of single phase auto transformer: (i) It has only one winding wound on a laminated circular magnetic core. (ii) The core is made of silicon steel stampings. (iii) The two terminals of the ... help of handle. 5) The same transformer can be used as step-up or step down auto-transformer
Description : Explain construction and working principle of single phase transformer.
Last Answer : A single phase transformers is an electrical device that accepts single-phase AC power and outputs single-phase AC. PRINCIPLE... The single-phase transformer works on the principle of ... and secondary windings. Thin steel laminations shall be employed to prevent power losses from the core.