# Electrical Circuits and Machines

**Digital electronics** or **digital (electronic) circuits** are electronics that handle digital signals (discrete bands of analog levels). All levels within a band of values represent the same information state. In most cases, the number of these states is **two**, and they are represented by two voltage bands. These correspond to the **false** and **true** values respectively of the Boolean domain.

In contrast, **analog circuits** operate on analog signals whose performance is more subject to manufacturing tolerance, signal attenuation and noise. **Digital techniques are useful** because it is easier to get an electronic device to switch into one of a number of known states than to accurately reproduce a continuous range of values.

Digital electronic circuits are usually made from **large assemblies of** logic gates (often printed on integrated circuits), simple electronic representations of Boolean logic functions.

## Overview

**Electrical Circuits and Machines**

Abbreviation | DE | ||||||
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Course | SE | ||||||

Credits | |||||||

Examination Scheme
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Language | English |

## Table of Contents

## Course Objectives

To analyse AC and DC networks with network simplification techniques. • To gain basic knowledge of transformers and their types. • To conduct experimental procedures on different types of electrical machines. • To understand the constructional details, characteristics, features and application areas ofvarious types of electric motors.

## Course Outcomes

Having successfully completed this course, the student will be able to:

- Analyze basic AC & DC circuit for voltage, current and power by using KVL, KCL, andnetwork theorems. 2. Explain the working principle of different electrical machines. 3. Select proper electrical motor for given application. 4. Design and analyze transformers.

## Syllabus and Notes

### Unit 1: Basic Circuit Analysis and Simplification Techniques

Main Page: Basic Circuit Analysis and Simplification Techniques

- Types, Construction, Transformer on No-load (Transformation ratio, emf equation), impedance transformation, losses in transformer, regulation and efficiency, rating. Auto transformer, coupling transformer, Isolation transformer, C.T. and P.T., Design of single phase transformer for instrument power supply, High frequency transformers.

### Unit 2: Transformer

Main Page: Transformer

- Types, Construction, Transformer on No-load (Transformation ratio, emf equation), impedance transformation, losses in transformer, regulation and efficiency, rating. Auto transformer, coupling transformer, Isolation transformer, C.T. and P.T., Design of single phase transformer for instrument power supply, High frequency transformers.

### Unit 3: DC Machines

Main Page: DC Machines

- Construction of DC Machine, Motoring and generation action, types, EMF equation, Torque equation (Torque-armature current characteristics, Torque-speed characteristics, speed-armature current characteristics), Power flow diagram. Problems on speed, torque & losses. Different methods of speed control, different types of starters for DC shunt motor. Permanent Magnet DC motors, Applications of DC Motors

### Unit 4: AC Motors

Main Page: AC Motors

- Three phase Induction motors, construction and principle of operation, types, slip and torque equation, Torque-slip characteristics, condition for maximum torque & ratios, types of starters, speed control, V/f control, Applications. Synchronous motors: Construction, principle of operation, characteristics (V curves) and applications.

### Unit 5: Special Motors 1

Main Page: Special Motors 1

- BLDC Motor, Construction, principle, characteristics, control circuit, sensors, applications. Construction, principle & applications of Reluctance Motor, Universal Moto

### Unit 6: Special Motors 2

Main Page: Special Motors 2

- Construction, types, principle, Characteristics, control circuit & applications of Stepper Motor and Servo motor. Construction, principle, characteristics, Types and applications of single phase Induction Motor.

**List of Experiments**:

Network Theorems : To verify Thevenin’s and Norton’s theorem ( DC or AC) 2. O.C. And S.C. Test on single phase transformer 3. Polarity test on single phase transformer. 4. Equivalent Circuit of a Single Phase Induction Motor by performing the no- load and blocked rotor tests. 5. Study of BLDC Motor Drive. 6. Speed control of DC motor using armature voltage and field current control method. Measure RPM and plot graph of speed versus armature voltage and field current. 7. Load test on 3-phase induction motor 8. Determination of equivalent circuit parameters of 3-phase induction motor using no load & blocked-rotor test. 9. To plot speed- torque characteristic of three phase induction motor. 10. To study various operating modes of stepper motor.

## Previous Years Questions

- Pattern 2012 and 2015 Question Papers

## Practical/ Oral Exam Questions

## Multiple choice questions

Unit 1 | Unit 2 |

Unit 3 | Unit 4 |

## Assignments

Assignment 1 | Assignment 2 |

Assignment 3 | Assignment 4 |

Assignment 5 | Assignment 6 |

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## References

- UniPune
- Wikipedia
- WikiNote Foundation