Bissoy.com
Doctors Medicines MCQs Q&A

Consider the following statements regarding parallel connection of 3-phase transformers: 1. The secondaries of all transformers must have the same phase sequence. 2. The phase displacement between primary and secondary line voltages must be the same for all transformers which are to be operated in parallel. 3. The primaries of all transformers must have the same magnitude of line voltage. Which of the above statements are correct?

Consider the following statements regarding parallel connection of 3-phase transformers: 1. The secondaries of all transformers must have the same phase sequence. 2. The phase displacement between primary and secondary line voltages must be the same for all transformers which are to be operated in parallel. 3. The primaries of all transformers must have the same magnitude of line voltage. Which of the above statements are correct? Correct Answer 1, 2 and 3

Necessary conditions for parallel operation of transformers:

  1. Voltage ratings mentioned on the nameplate of the transformers to be connected in parallel must be the same means the primaries of all the transformed must have the same magnitude of line voltage.
  2. The transformers must be connected in parallel with the correct polarity.
  3. The phase sequence of the secondaries of all transformers to be connected in parallel must be the same.
  4. As a part of the phase sequence matching the phase displacement between primary and secondary line voltages must be the same for all transformers. This condition can be fulfilled if all transformers belong to the same phasor group.

 

Desirable condition for parallel operation of transformers:

  • The voltage ratios of the transformer to be connected in parallel should be the same to avoid circulating currents.
  • All the transformers should share the common load proportional to their kVA ratings.
  • The (X /R) ratio of transformers should be equal to avoid the operation of transformers at different power factors.

Related Questions

At an Electronic Data processing unit, five out of the eight program sets P,Q,R,S,T,U,V and W are to be operated daily. On any one day, except for the first day of a month, only three of the program sets must be the ones that were operated on the previous day. The program operating must also satisfy the following conditions: 1. If program P is to be operated on a day, V can’t be operated on that day. 2. If Q is to be operated on a day, T must be one of the programs to be operated after Q. 3. If R is to be operated on a day, V must be one of the programs to be operated after R. 4. The last program to be operated on any day must be either S or U. If the program sets R and W are to be operated on the first day, which of the following could be the other program on that day?
When a 1-phase transformer is connected in parallel, there are four conditions for proper parallel operation, but when two or 3-phase transformer paralleling is done, there are two additional points along with those four conditions applied for 1-phase. Statement 1 - The phase sequence must be the same. Statement 2 - The phase shift between primary and secondary voltages must be the same for all transformers connected in parallel. From the above two Statements (s), which is/are the correct conditions in this regard?
A three-phase transformer consists of transformers either combined or separated on one core. The primaries and the secondaries can be connected in star or delta independently, Which of these is a part of the three-phase transformer connections and is used to perform a three-phase conversion?
The conditions regarding selection from a list of suitable candidates to be called for interview after a written examination for appointment of management-level persons to a multi-national company providing accounting services and sales are mentioned below. Candidates: a) Must have a Bachelor's degree in Basic Science with 65% or more marks or BE with 55% or more marks. b) Must have passed the examination with 70% or more marks. c) Age must be between 25 to 30 years as of 1/4/18. d) Must have 3 years of experience in an Accounting Institution and must have a Diploma in Accounting with 60% or more marks. e) Must be currently getting CTC of Rs. 6 lakh or more per annum. If the candidate: 1) If he fulfills all the other conditions other than A above, he will be designated as Junior Accountant. 2) If he fulfills all the other conditions other than (d) and (e) above, he can be designated as Trainee-Accountant. If he fulfills all the above conditions including 5 years of experience, he can be designated as a Senior Accountant. He can be designated as Manager (Accounts) if he fulfills all the above criteria including educational qualifications of CA/ ICWA/ MBA (Finance). Study all the above information and answer the following question. Varun has passed the CA exam and has a bachelor's degree in basic science and a diploma in accountancy, having scored 75% or more in the written examination during his entire career and also in the written examination. His age is 27 years and with 4 years of experience in Accountancy, he has a CTC salary of 18 lakhs per annum. To which of the following positions can he be referred? Select from the given options.
The following are the conditions for selecting list of a suitable candidates to be called for interview after the written test for the recruitment is conducted/ organized for management-level persons of a multi-national company. For providing accounting services and sales the candidates must (a) be holding a graduation in basic science with 65% or above or B. E degree with 55% and above marks (b) have passed the written test with 70% or above marks (c) the age must be in the group 25 to 30 years as on 1/4/18 (d) have experience in an accounting firms for three years and diploma in accounting with 60% or above marks (e) be presently drawing CTC of 6 Lakhs per annum and above In case the applicant who satisfies all other terms above except 1) at (a) above, then be referred as Junior Accountant 2) at (d) & (e) above then be referred as Trainee-Accountant Satisfying all the above with experience of 5 years then be referred as senior-Accountant Satisfying all the above criteria (a-e) with CA/ ICWA / MBA (Finance) then be refereed as manager (Accounts) Read all the above information and answer the following question Shravani has passed H. SC with 72% of marks. She has done diploma in accountancy with 62% of marks. She was working with an organization in the field of accounting in the field of accounting from 4 years and was drawing CTC of 6.5 Lakhs presently. She is 28yrs as on July 2018. She may referred for the position of:
The following are the conditions for selecting list of a suitable candidates to be called for interview after the written test for the recruitment is conducted/organized for management - level persons for a multi - national company. For providing accounting services and sales the candidate must (a) be holding a graduation in basic science with 65% or above or B.E. degree with 55% and above marks (b) have passed the written test with 70% or above marks (c) the age must be in the group 25 to 30 years as on 1/4/18 (d) have experience in an accounting firms for three years and diploma in accounting with 60% or above marks (e)  be presently drawing CTC of 6 Lakhs per annum and above In case the applicant who satisfies all other terms above except 1) at (a) above, then be referred as Junior Accountant 2) at (d) & (e) above then be referred as Trainee - Accountant Satisfying all the above with experience of 5 years then the referred as senior-Accountant Satisfying all the above criteria (a - e) with CA/ICWA/MBA (Finance) then be referred as manager (Accounts) Read all the above information and answer the following question Praveen has done his Masters in physics. He has no experience in accounting neither diploma. He is ready to be on training for accounting after joining. For which position he may be referred
The following are the conditions for selecting a list of suitable candidates to be called for interview after the written test for the recruitment is conducted/ organized for management-level persons for a multi-national company. For providing accounting services and sales the candidate must (a) beholding graduation in basic science with 65% or above or B.E. degree with 55% and above marks (b) have passed the written test with 70% or above marks (c) the age must be in the group 25 to 30 years as on 1/4/18 (d) have experience in an accounting firm for three years and a diploma in accounting with 60% or above marks e) be presently drawing CTC 6 lakhs per annum and above In case the applicant who satisfies all other terms above except 1) at (a) above, then be referred to as Junior Accountant 2) at (d) & (e) above then be referred to as Trainee-Accountant Satisfying all the above with experience of 5 years then be referred to as senior-Accountant Satisfying all the above criteria (a-e) with CA/ICWA/MBA (Finance) then be referred to as manager (Accounts) Read all the above information and answer the following question   Praveen has done his Masters in physics. He has no experience in accounting neither diploma. He is ready to be on training for accounting after joining. For which position he may be referred.
The following are the conditions for selecting list of a suitable candidates to be called for interview after the written test for the recruitment is conducted/ organized for management-level persons of a multi-national company. For providing accounting services and sales the candidate must (a) be holding a graduation in basic science with 65% or above or B.E degree with 55% and above marks (b) have passed the written test with 70% or above marks (c) the age must be in the group 25 to 30 yrs as on 1/4/18 (d) have experience in an accounting firms for three yrs and diploma in accounting with 60% or above marks (e) be presently drawing CTC of 6 Lakhs per annum and above In case the applicant who satisfies all other terms above except 1) at (a) above, then be referred as Junior Accountant 2) at (d) & (e) above then be referred as Trainee-Accountant Satisfying all the above with experience of 5 yrs then be referred as senior-Accountant Satisfying all the above criteria (a-e) with CA/ ICWA/ MBA (Finance) then be refereed as manager (Accounts) Read all the above information and answer the following question: Radha Mohan has done her graduation in physics with 58% of marks. She has passed the written examination with 76% of marks. She is 27 yrs as on June 2018. She has the experience in the accounting company for four years with salary of 7 Lakhs per annum. She also has passed diploma in accounting with 61% of marks. She may be referred for the position of:
In context of a three phase transformer, what is the angle difference between the phase voltages in primary and secondary sides if the primary side is connected in star and secondary side is connected in delta connection?
Consider the following statements regarding parallel operation of transformer’s 1. Transformers must be operated at same frequency 2. Transformers must have equal voltage ratings Which of the following statements is/are correct?