Exam Details
| Subject | Electrical Machines-I | |
| Paper | ||
| Exam / Course | Diploma -VIEP-Electrical Engineering (DELVI)/Advanced Level Certificate Course In Electrical Engineering (ACELVI) | |
| Department | School of Engineering & Technology (SOET) | |
| Organization | indira gandhi national open university | |
| Position | ||
| Exam Date | June, 2015 | |
| City, State | new delhi, |
Question Paper
1. Attempt all the parts.
Back emf of a DC motor is proportional to
Speed
Flux
Both and
Neither nor
Brushes in a DC machine are made of
Asphalt
Graphite
Diamond
Copper
In a DC shunt motor, if flux decreases
speed increases.
speed decreases
speed remains same
None of the above
Temperature rise can be determined in the transformer by
Open circuit test
Short circuit test
Load test
Sumpner test
The hysteresis loss in the transformer core
remains constant with load changing
is proportional to frequency
depends on thickness of core
depends on secondary current
Scott connection is used for
two phase to single phase conversion
three phase to two phase conversion
three phase to twelve phase conversion
parallel operation of transformers
Interpoles are used in
DC machines
Induction motor
Transformer
Speed control
Derive the equation for induced emf of a DC machine.
A shunt generator gives full load output of 30 kW at a terminal voltage of 200 V. The armature and field resistances are 0·05 ohm and 50 ohm respectively. Calculate the generated emf.
What are the different tests conducted on a DC machine? Explain Swinburne test.
Why are starters needed in a DC machine? Explain 3-point starter with a neat diagram.
A 460 V series motor runs at 500 rpm taking a current of 40 A. Calculate the speed and percentage change in torque, if the load is reduced and motor takes 30 A. Total resistance of the armature and field circuit is 0·8 ohm.
What are the applications of DC series, DC shunt and compound motors?
Obtain the equivalent circuit of a single phase transformer referred to primary side. Define the parameters involved.
What are the advantages and disadvantages of auto transformers compared to two winding transformers?
In a transformer, the core loss is 100 W at 40 Hz and 72 W at 30 Hz. Find the hysteresis and eddy current losses at 50Hz.
What are the differences between Power and Distribution transformers
Draw the connection diagram and phasor diagram for the following three-phase transformer configurations
Delta -Delta
Star -Delta
Explain the phenomenon of inrush current in transformers.
8. Write short notes on any four of the following:
Lap and Wave type armature winding
Compounded DC generators
Losses in transformer
Ward-Leonard method of speed control
DC motor characteristics
Tap changing transformer
No-load current
Back emf of a DC motor is proportional to
Speed
Flux
Both and
Neither nor
Brushes in a DC machine are made of
Asphalt
Graphite
Diamond
Copper
In a DC shunt motor, if flux decreases
speed increases.
speed decreases
speed remains same
None of the above
Temperature rise can be determined in the transformer by
Open circuit test
Short circuit test
Load test
Sumpner test
The hysteresis loss in the transformer core
remains constant with load changing
is proportional to frequency
depends on thickness of core
depends on secondary current
Scott connection is used for
two phase to single phase conversion
three phase to two phase conversion
three phase to twelve phase conversion
parallel operation of transformers
Interpoles are used in
DC machines
Induction motor
Transformer
Speed control
Derive the equation for induced emf of a DC machine.
A shunt generator gives full load output of 30 kW at a terminal voltage of 200 V. The armature and field resistances are 0·05 ohm and 50 ohm respectively. Calculate the generated emf.
What are the different tests conducted on a DC machine? Explain Swinburne test.
Why are starters needed in a DC machine? Explain 3-point starter with a neat diagram.
A 460 V series motor runs at 500 rpm taking a current of 40 A. Calculate the speed and percentage change in torque, if the load is reduced and motor takes 30 A. Total resistance of the armature and field circuit is 0·8 ohm.
What are the applications of DC series, DC shunt and compound motors?
Obtain the equivalent circuit of a single phase transformer referred to primary side. Define the parameters involved.
What are the advantages and disadvantages of auto transformers compared to two winding transformers?
In a transformer, the core loss is 100 W at 40 Hz and 72 W at 30 Hz. Find the hysteresis and eddy current losses at 50Hz.
What are the differences between Power and Distribution transformers
Draw the connection diagram and phasor diagram for the following three-phase transformer configurations
Delta -Delta
Star -Delta
Explain the phenomenon of inrush current in transformers.
8. Write short notes on any four of the following:
Lap and Wave type armature winding
Compounded DC generators
Losses in transformer
Ward-Leonard method of speed control
DC motor characteristics
Tap changing transformer
No-load current
Other Question Papers
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Subjects
- Basics of Electrical Engineering
- C - Programming
- Computer Applications In P.S.
- Control Systems
- Digital Control System
- Digital Control System Design
- Dynamics System Simulation
- Electrical Circuit Theory
- Electrical Engineering Material
- Electrical Installation and System
- E l e c t r i c a l M a c h i n e T h e o r y I I
- Electrical Machines-I
- Electrical Measurements And Instruments
- Electrical Power Transmission and Distribution
- Energy Audit
- Flexible Ac Transmission System
- Industrial Drives and Controls
- Mechatronics
- Power Generation System
- Power Plant Economics And Centering
- Power System Reliability
- Principles of Computer Architecture
- Special Electrical Machines
- Switchgear And Protection
- Utilization Of Electrical Engineering