Delmar's Standard Textbook of Electricity (MindTap Course List)
6th Edition
ISBN: 9781285852706
Author: Stephen L. Herman
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 29, Problem 1RQ
How many transformers are needed to make an open-delta connection?
Expert Solution & Answer
To determine
The number of transformers needed to make an open delta connection.
Answer to Problem 1RQ
Two transformers are needed to make an open delta connection.
Explanation of Solution
The open delta connection is used when the amount of three-phase power needed is not excessive. From the figure it can be seen that the open-delta transformer connection can be made with only two transformers. The total output power is 86.6% of the sum of the power rating of the two transformers when an open-delta connection is used.
Want to see more full solutions like this?
Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
How many types of winding in distribution transformers? What is the impact of each type on calculations zero sequence impedance ?
Why is zero sequence impedance important in Zigzag transformers and grounding transformers ?
Mention the types of iron cores in the transformers and the effect of the shape of the iron core in the calculation zero sequence impedance in transformers?
Chapter 29 Solutions
Delmar's Standard Textbook of Electricity (MindTap Course List)
Ch. 29 - How many transformers are needed to make an...Ch. 29 - Two transformers rated at 100 kVA each are...Ch. 29 - How does the NEC specify that the high leg of a...Ch. 29 - An open-delta three-phase transformer system has...Ch. 29 - If a single-phase load is connected across the two...Ch. 29 - A three-phase transformer connection has a...Ch. 29 - A three-phase transformer connection has a...Ch. 29 - A three-phase transformer bank has the secondary...Ch. 29 - A three-phase transformer bank has the primary and...Ch. 29 - Referring to the transformer connection in...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- What two types of chime transformers for Class 2 systems are listed by UL? ___________________________ ___________________________arrow_forwardWhat is the maximum volt-ampere rating of transformers supplying Class 2 systems? ___________arrow_forwardFor large power transformers rated more than 500 kVA, the winding resistances, which are small compared with the leakage reactances, can often be neglected. (a) True (b) Falsearrow_forward
- In per-unit equivalent circuits of practical three-phase transformers, under balanced thr-phase operation, in which of the following connect ions would a phase-shifting transformer come up? (a) Y-Y (b) Y- (c) -arrow_forwardThree single-phase two-winding transformers, each rated 3kVA,220/110volts,60Hz, with a 0.10 per-unit leakage reactance, are connected as a three-phase extended autotransformer bank, as shown in Figure 3.36(c). The low-voltage winding has a 110 volt rating. (a) Draw the positive-sequence phasor diagram and show that the high-voltage winding has a 479.5 volt rating. (b) A three-phase load connected to the low-voltage terminals absorbs 6 kW at 110 volts and at 0.8 power factor lagging. Draw the per-unit impedance diagram and calculate the voltage and current at the high-voltage terminals. Assume positive-sequence operation.arrow_forwardConsider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of three identical single-phase transformers, each specified by X1=0.24 (on the low-voltage side), negligible resistance and magnetizing current, and turns ratio =N2/N1=10. The transformer bank is delivering 100 MW at 0.8 p.f. lagging to a substation bus whose voltage is 230 kV. (a) Determine the primary current magnitude, primary voltage (line-to-line) magnitude, and the three-phase complex power supplied by the generator. Choose the line-to-neutral voltage at the bus, Va as the reference Account for the phase shift, and assume positive-sequence operation. (b) Find the phase shift between the primary and secondary voltages.arrow_forward
- What should be the focus of transformer preventive maintenance efforts?arrow_forwardThe ratings of a three-phase, three-winding transformer are Primary: Y connected, 66kV,15MVA Secondary: Y connected, 13.2kV,10MVA Tertiary: connected, 2.3kV,5MVA Neglecting resistances and exciting current, the leakage reactances are: XPS=0.09 per unit on a 15-MVA,66-kV base XPT=0.08 per unit on a 15-MVA,66-kV base XST=0.05 per unit on a 10-MVA,13.2-kV base Determine the per-unit reactances of the per-phase equivalent circuit using a base of 15 MVA and 66 kV for the primary.arrow_forwardIn order to avoid difficulties with third-harmonic exciting current, which three-phase transformer connection is seldom used for step-up transformers between a generator and a transmission line in power systems. (a) Y- (b) -Y (c) Y-Yarrow_forward
- Equipment ratings for the five-bus power system shown in Figure 7.15 are as follows: Generator G1:    50 MVA, 12kV, X=0.2 per unit Generator G2: 100 MVA, 15 kV, X=0.2 per unit Transformer T1: 50 MVA, 10 kV Y/138kVY,X=0.10 per unit Transformer T2: 100 MVA, 15 kV /138kVY,X=0.10 per unit Each 138-kV line: X1=40 A three-phase short circuit occurs at bus 5, where the prefault voltage is 15 kV. Prefault load current is neglected. (a) Draw the positive-sequence reactance diagram in unit on a 100-MVA, 15-kV base in the zone of generator G2. Determine (b) the Thévenin equivalent at the fault, (c) the subtransient fault current in per unit and in kA rms, and (d) contributions to the fault from generator G2 and from transformer T2.arrow_forwardWhat are two transform boundaries?arrow_forward3_ In Back To Back Test on Two Similar Single Phase transformers. What will be the current in the primary windings? i) When secondaries are not loaded ? ii) When secondaries are loaded ?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Delmar's Standard Textbook Of ElectricityElectrical EngineeringISBN:9781337900348Author:Stephen L. HermanPublisher:Cengage Learning
Power System Analysis and Design (MindTap Course ...Electrical EngineeringISBN:9781305632134Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. SarmaPublisher:Cengage Learning
EBK ELECTRICAL WIRING RESIDENTIALElectrical EngineeringISBN:9781337516549Author:SimmonsPublisher:CENGAGE LEARNING - CONSIGNMENT
Delmar's Standard Textbook Of Electricity
Electrical Engineering
ISBN:9781337900348
Author:Stephen L. Herman
Publisher:Cengage Learning
Power System Analysis and Design (MindTap Course ...
Electrical Engineering
ISBN:9781305632134
Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma
Publisher:Cengage Learning
EBK ELECTRICAL WIRING RESIDENTIAL
Electrical Engineering
ISBN:9781337516549
Author:Simmons
Publisher:CENGAGE LEARNING - CONSIGNMENT
TRANSFORMERS - What They Are, How They Work, How Electricians Size Them; Author: Electrician U;https://www.youtube.com/watch?v=tXPy4OE7ApE;License: Standard Youtube License