---
title: "Synchronous generator constructional diagram"
subject: "Basic Electrical and Electronics Engineering"
chapter: 2
key: "semester_1/basic_electrical_and_electronics_engineering:synchronous-generator-diagram"
source: https://www.bctengineer.com/q/semester_1/basic_electrical_and_electronics_engineering/synchronous-generator-diagram
site: BCT Engineering
---

# Synchronous generator constructional diagram

Basic Electrical and Electronics Engineering · Chapter 2: Electrical Machines

- Asked in: 2081 Baishakh (new course), 3 marks
- Video: [Synchronous Generator (Construction) Main parts of generator (1st year engineering) BEE/EEE](https://www.youtube.com/watch?v=7MUUXkFu6m4) — Gautam Varde
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_1/basic_electrical_and_electronics_engineering/synchronous-generator-diagram
- Whole chapter: https://www.bctengineer.com/md/semester_1/basic_electrical_and_electronics_engineering/chapter-2

## Question

Draw a constructional diagram of synchronous generator mentioning its components.

## Short answer

The stator houses a laminated core with three-phase armature winding. The rotor carries a field winding supplied with DC via slip rings and brushes, producing rotating flux. A prime mover drives the shaft to induce emf.

## Answer

A synchronous generator (alternator) has two main parts, the stator (armature) and the rotor (field).

```text
   Stator frame (cast iron / steel)
  +---------------------------------+
  |  Stator core (laminated steel)  |
  |   +-------------------------+   |
  |   |  armature winding in    |   |
  |   |  slots (3-phase)        |   |
  |   |    +---------------+    |   |
  |   |    | Rotor (field) |    |   |
  |   |    |   N   [shaft] |    |   |
  |   |    |       S       |    |   |
  |   |    +---------------+    |   |
  |   +-------------------------+   |
  +---------------------------------+
    Slip rings + brushes -> DC supply
    (exciter) to field winding
    Prime mover coupled to the shaft
```

**Components:**
1. **Stator frame:** the outer cast-iron or steel body that supports the core and protects the machine.
2. **Stator core:** laminated silicon-steel stampings with slots on the inner surface; the laminations reduce eddy-current loss.
3. **Armature winding:** a three-phase winding placed in the slots, in which the emf is induced and from which the output is taken.
4. **Rotor:** carries the DC field winding; it is either salient-pole (low speed, hydro) or cylindrical (high speed, turbo).
5. **Field winding:** supplied with DC through slip rings and carbon brushes, producing the main flux.
6. **Exciter:** a small DC source (a DC generator on the shaft or a static rectifier) that supplies the field current.
7. **Shaft and bearings:** transmit the prime mover's torque to the rotor.
8. **Air gap and cooling system:** a small air gap separates the rotor and stator, and fans or ducts carry away the heat.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What are the two main parts of a synchronous generator?
   A. Commutator and brushes
   B. Yoke and pole shoe
   C. Primary and secondary windings
   D. Stator (armature) and rotor (field)
   Answer: D. The stator carries the armature winding; the rotor carries the field winding. (Key point: Main parts)

2. How is the rotor field winding supplied?
   A. With DC through slip rings and carbon brushes from an exciter
   B. With AC from the grid directly
   C. Through a commutator
   D. It uses permanent magnets only
   Answer: A. A DC exciter supplies the field via slip rings and brushes to produce the main flux. (Key point: Field excitation)

3. Why is the stator core made of laminated silicon steel, and which rotor suits hydro plants?
   A. To increase eddy currents; cylindrical rotor
   B. To reduce eddy-current loss; salient-pole rotor (low speed)
   C. To reduce copper loss; cylindrical rotor
   D. To raise flux leakage; salient-pole rotor at high speed
   Answer: B. Laminations reduce eddy losses, and low-speed hydro machines use salient-pole rotors while high-speed turbo sets use cylindrical rotors. (Key point: Stator core and rotor types)

## Related in Basic Electrical and Electronics Engineering

- [Synchronous generator working principle](https://www.bctengineer.com/question.md?key=semester_1%2Fbasic_electrical_and_electronics_engineering%3Asynchronous-generator-principle) — Basic Electrical and Electronics Engineering, chapter 2

## Related in other subjects

- [3-phase synchronous generator construction](https://www.bctengineer.com/question.md?key=semester_4%2Felectrical_machine%3Async-generator-construction-working) — Electrical Machine, chapter 6
- [Synchronous generator load characteristics, capacitive load](https://www.bctengineer.com/question.md?key=semester_4%2Felectrical_machines%3Async-gen-load-characteristics-capacitive) — Electrical Machines, chapter 6
- [Armature reaction in synchronous generator](https://www.bctengineer.com/question.md?key=semester_4%2Felectrical_machines%3Aarmature-reaction-sync-gen-loads) — Electrical Machines, chapter 6
- [Armature reaction in synchronous generator](https://www.bctengineer.com/question.md?key=semester_4%2Felectrical_machine%3Aarmature-reaction-sync-generator-loads) — Electrical Machine, chapter 6, asked 2×