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.
****************************************************************************
| 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!!!!!!!******** | |||
