A manufacturing company has privately contracted your company to rewire the mechanical workshop in the building. During a site visit, you observed that the building receives a 400V, 60HZ, star-connected, three-phase supply from the utility. There are also several three-phase equipment in the workshop including bench lathes, drill presses and welding machines that require a 230V three-phase supply. You have decided to utilize three single-phase, dry type transformers to step down the building's incoming supply to a 230V, delta-connected supply for the equipment. All the three-phase machinery can be modelled as an equivalent balanced three-phase star- connected load with a resistance and inductance of 0.52 and 0.16mH respectively per phase. Some preliminary calculations and analysis are required before starting the wiring design. a) Draw a labelled diagram of the entire three phase system clearly showing all known voltages (phase and line values) and the three phase configurations of all components.

A manufacturing company has privately contracted your company to rewire the mechanical workshop in the building. During a site visit, you observed that the building receives a 400V, 60HZ, star-connected, three-phase supply from the utility. There are also several three-phase equipment in the workshop including bench lathes, drill presses and welding machines that require a 230V three-phase supply. You have decided to utilize three single-phase, dry type transformers to step down the building's incoming supply to a 230V, delta-connected supply for the equipment. All the three-phase machinery can be modelled as an equivalent balanced three-phase star- connected load with a resistance and inductance of 0.52 and 0.16mH respectively per phase. Some preliminary calculations and analysis are required before starting the wiring design. a) Draw a labelled diagram of the entire three phase system clearly showing all known voltages (phase and line values) and the three phase configurations of all components.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

See similar textbooks

Similar questions

a)The voltage per winding of 220V/12V, 60 Hz single phase core transformer is 1V. If the maximum flux density in the core is 1.5 T, which of the following is the cross-sectional area of the core in cm²? 0.0030 0.0060 30 25 50 0.0050 0.0025 60 b) The voltage per winding of 220V/12V, 50 Hz single phase core transformer is 2V. If the maximum flux density in the core is 1.5 T, which of the following is the cross-sectional area of the core in cm²? 0.0030 0.0060 30 25 60 0.0050 0.0025 50
Two transformers A and B of ratings 500 KVA and 250 KVA are supplying a load KVA of 750 at e.8 Pflagging, their open circuit voltages are 400 volt and 410 volt respectively. Transformer A has 1% resistance and 5% reactance and transformer B has 1.5% resistance and 4% reactance. Find ( a ) Cross - current in the secondaries on no - load , ( b ) the load shared by each transformer .
A 50Hz, single phase transformer has a ratio of N2:N1 = 0.2. On full-load, the secondary current is 200A. The resistance and reactance of the primary winding are 0.8 ohm and 4 ohm respectively. The corresponding values for the secondary winding are 0.04 ohm and 0.1 ohm. If the secondary is short circuited, what voltage must be applied to the primary to produce full-load current? What will be the copper loss?
A 12 MVA, 132/6.6 kV, transformer having a reactance of 0.15 pu is fed from an infinite bus. The transformer feeds two motor each 6 MVA, 6.6 kV. Each motors has a transient reactance of 0.14 pu and a subtransient reactance of 0.30 pu based on its own rating. A three phase balanced fault occurs at the terminals of one motor as shown in the figure below. Find the subtransient fault current and subtransient current in breaker. M1) 132/6.6 KV СВ 38 CB Infinite Bus M2 Fault
A 10 kVA, single-phase transformer has a turns ratio of 12:1 and is supplied from a 2.4 kV supply. Neglecting losses, determine (a) the full load secondary current, (b) the minimum value of load resistance which can be connected across the secondary winding without the kVA rating being exceeded, and (c) the primary current.
The required no-load voltage ratio in a 150 kVA single-phase 50 Hz core-type, two-winding transformer is 5000/250 V. Calculate the load kVA for maximum efficiency. The full-load I2R loss is 1800 W and the core loss is 1500 W. Round your answer off to the nearest whole number
a single-phase transformer serves a 7.2kw resistive loadlocated 200 ft from the transformer. each conductor from the transformer to load has an impedence of (0.78+j0.052) ohms per 1000ft. if the voltage at the load terminal is 240v, the magnitude of the voltage (v) at the transformer secondary is most nearly:
The equivalent circuit impedances of a 20-kVA, 8000/240-V, 60-Hz transformer are to be determined. The open-circuit test and the short- circuit test were performed on the primary side of the transformer, and the following data were taken: Open-circuit test (on primary) Short-circuit test (on primary) 8000 V V= 489 V I0.214 A 2.5 A P= 400 W P= 240 W Find the impedances of the approximate equivalent circuit referred to the primary side, and sketch the circuit.
Ql-phase step down transformer 1250 KVA, 11000/2200 V, 50 Hz . The resistance /phase and leakage reactance/phase of the primary winding are 0.78 N and 4.80 and the corresponding values for the secondary winding are 0.012 and 0.062 respectively if the primary winding is connected in delta and secondary in star calculate: i)The voltage to be applied at normal frequency to the primary to circulate full-load through it when the secondary is short-circuited Ii) The full load copper loss
2) 9.2Three - 25 KVA single-phase transformers are connected in delta – delta. One of the transformers has been defected. What is the maximum real power that the transformer bank can deliver at a power factor of 0.8?
The nameplate on a 25-MVA, 60-Hz single-phase transformer indicates that it has a voltage rating of 8.0-kV:78-kV. A short-circuit test from the high-voltage side (low-voltage winding shortcircuited) gives readings of 4.53 kV, 321 A, and 77.5 kW. An open-circuit test is conducted fromthe low-voltage side and the corresponding instrument readings are 8.0 kV, 39.6 A, and 86.2 kW. (a) Calculate the equivalent series impedance of the transformer as referred to the high-voltageterminals.(b) Calculate the equivalent series impedance of the transformer as referred to the low-voltageterminals.(c) Making appropriate approximations, draw a T equivalent circuit for the transformer.(d) Determine the efficiency of the transformer if it is supplying rated load (unity power factor)at rated voltage at its low-voltage terminal
Draw the basic circuit of 2 stages cascaded transformers if the apparent power of the last stage is 75 KVA. The voltage of Primary and tertiary exciting windings for each transformer is 220 V, and the voltage of secondary winding is 150 kV.*