Dear Friends,
Here I attach the MOST IMP Questions for DCMT (DC Machine) subject.
Practice Paper prepared by Aakash Sir.
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Here I attach the MOST IMP Questions for DCMT (DC Machine) subject.
Practice Paper prepared by Aakash Sir.
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ET ROLL NO :____________ GTU Enrollment no:________________ | |||
ELECTRO TUTOR, RAOPURA | |||
PRE GTU EXAM | |||
DIPLOMA ENGINEERING – SEMESTER – III • OCTOBER EXAM 2018 | |||
Subject Code: 3330902 Date: 04-10-2018 | |||
Subject Name: DC MACHINES AND TRANSFORMER | |||
Time: 5.00 PM to 7.30 PM Total Marks: 70 | |||
Instructions: | |||
1. Attempt all questions. | |||
2. Make suitable assumptions wherever necessary. | |||
3. Figures to the right indicates the full marks. | |||
4. Each question carries equal marks (14 marks) | |||
Q.1 | Answer any seven out of ten. | 14 | |
1 | Define (1) Pole Pitch (2) Back Pitch | ||
2 | List the different types of losses occurring in DC motor. | ||
3 | State the application of Auto transformer. | ||
4 | The necessity of commutator in d.c. generator. | ||
5 | Classify the different types of d.c. generator | ||
6 | What is Armature reaction in d.c. generator? | ||
7 | Write the basic principle of d.c. motor. | ||
8 | List the speed control of d.c. shunt motor and d.c. series motor. | ||
9 | Explain the power stages and various losses occurring in D.C. motor. | ||
10 | Explain the need for parallel operation. | ||
Q.2 | (a) | Derive the emf equation for single phase transformer. | 4 |
OR | |||
(a) | Write the equation of torque for DC motor and factors affecting the value of torque for DC motor. | ||
(b) | Explain different losses occurring in the transformer. | 3 | |
OR | |||
(b) | Explain the principle of motor action. | ||
(c) | Write the application of D.C. motor. | 3 | |
OR | |||
(c) | State advantages and disadvantages of Autotransformer | ||
(d) | Explain the construction of welding transformer. | 4 | |
OR | |||
(d) | Draw & explain Speed-current and Speed torque characteristics of a DC Shunt motor. | ||
Q.3 | (a) | Explain Swinburn’s Test of D.C. machine. | 3 |
OR | |||
(a) | Explain the direct loading test of the transformer. | ||
(b) | Explain the O.C & S.C. test to find out the efficiency of the transformer. | 4 | |
OR | |||
(b) | Explain the brake test to find the efficiency for D.C. motor. | ||
(c) | Explain different types of D.C. generators with circuit diagram. | 3 | |
OR | |||
(c) | Explain the difference between the three point starter and four-point starter. | ||
(d) | Draw and explain speed and armature current characteristics of DC series motor. | 4 | |
Q.4 | (a) | Draw and explain the working of three-point DC shunt motor starter and four-point starter. | 7 |
(b) | Explain the starting and running characteristics of the D.C. motor. | 7 | |
Q.5 | (a) | Explain the construction of D.C. machine with neat sketch and function of each part. | 7 |
(b) | Explain necessity and required conditions for parallel operation of two 1- phase transformers. | 7 | |
********BEST OF LUCK!!!!!!!******** | |||
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