Find the turns ratio of three single-phase transformers connected to form a three-phase system with characteristics given below: Primary side connection: Delta Primary side line voltage: 139kV Secondary side connection: Star Secondary side line voltage: 6kV Answer: Question 19 A three-phase induction machine running at rated load has the following characteristics: Supply Voltage: {V}V Supply frequency: 50HZ Number of poles: 4 Rotor speed: 1421 rpm Calculate the slip speed of the induction motor in rpm.

Find the turns ratio of three single-phase transformers connected to form a three-phase system with characteristics given below: Primary side connection: Delta Primary side line voltage: 139kV Secondary side connection: Star Secondary side line voltage: 6kV Answer: Question 19 A three-phase induction machine running at rated load has the following characteristics: Supply Voltage: {V}V Supply frequency: 50HZ Number of poles: 4 Rotor speed: 1421 rpm Calculate the slip speed of the induction motor in rpm.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.43P: Three single-phase transformers, each rated 10MVA,66.4/12.5kV,60Hz, with an equivalent series...

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An infinite bus, which is a constant voltage source, is connected to the primary of the three-winding transformer of Problem 3.53. A 7.5-MVA,13.2-kV synchronous motor with a sub transient reactance of 0.2 per unit is connected to the transformer secondary. A5-MW,2.3-kV three-phase resistive load is connected to the tertiary Choosing a base of 66 kV and 15 MVA in the primary, draw the impedance diagram of the system showing per-unit impedances. Neglect transformer exciting current, phase shifts, and all resistances except the resistive load.
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How many transformers are needed to make an open-delta connection?
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(a) An ideal single-phase two-winding transformer with turns ratio at=N1/N2 is connected with a series impedance Z2 across winding 2. If one wants to replace Z2, with a series impedance Z1 across winding 1 and keep the terminal behavior of the two circuits to be identical, find Z1 in terms of Z2. (b) Would the above result be true if instead of a series impedance there is a shunt impedance? (c) Can one refer a ladder network on the secondary (2) side to the primary (1) side simply by multiplying every impedance byat2 ?
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