Module 1 Flashcards
Are widely used for the
purpose of converting energy
from one form to another.
Rotating Electrical Machines
Takes place between well known Pairs of FORMS OF ENERGY
Energy Conversion Process
7 Types of Energy
Mechanical, Electrical, Sound, Chemical, Light, Heat, Nuclear
This law states that energy can neither be created nor destroyed. It can only be transformed from one form to another.
First Law of Thermodynamics: “Law of Conservation of Energy”
When energy is transformed from one form to another, some of the input energy is turned into a highly disordered form of energy, like heat,
which resulted to energy loss.
Second Law of Thermodynamics: “Law of Increased Entropy”
A device, having a unique purpose, that augments or replaces human or animal effort for the
accomplishment of physical tasks.
Machine
Is a rotary electro-mechanical energy conversion device that converts mechanical energy to
direct current (DC) electrical energy or DC electrical energy to mechanical energy.
DC Machine
Conversion of Energy in Electrical Generator
Mechanical Energy to Electrical Energy
Conversion of Energy in Electrical Motor
Electrical Energy to Mechanical Energy
A machine generates electrical energy for use in
an external circuit.
Electric Generator
A mechanical machine that drives (rotates) the electrical generator
Prime mover
an initial source of motive power (rotation) designed to receive and modify force and motion as supplied by some natural or chemical source and apply them to drive a machinery.
Prime Mover
A machinery that produces
rotational mechanical energy
to drive external physical loads.
Electrical Motor
“Whenever a conductor is placed in a varying magnetic
field, an electromotive force is induced.”
Faraday’s Fist Law of Electromagnetic Induction
the stationary part of the DC generator
Stator
The moving/rotating part of the DC generator
Rotor
– magnets or electromagnets that creates magnetic lines of force to
be cut by the armature conductors.
– always work in pairs
Poles
– houses the entire machine
– where the magnets/poles are mounted.
Yoke
– holds the poles together and spread the flux evenly.
Pole Shoe
Parts of a DC Generator that are under the Stator
Yoke, Pole Shoe, Pole
– a laminated steel core that holds and contains the current carrying
conductors (windings) on its conductor slots.
– also called as the armature core
Core
– copper conductors that are wounded around the core that cuts
the magnetic lines of force.
– also called as the armature conductors
Windings
– coupled/connected to the prime mover that rotates the core.
Shaft
Parts of a DC Generator that are under the Rotor
Core, Windings, Shaft
termination point of the armature
windings and periodically reverses the direction of the
current flow to an external circuit.
Commutator
makes the current change direction every half-rotation.
Split Rings
merely maintains a connection between the moving
rotor and the stationary stator. No commutation
process occurring.
Slip Ring
harvest the current from the rotating
commutator. It always work in pairs.
Carbon Brushes
“The magnitude of the generated voltage is directly proportional to the rate at
which a conductor cuts magnetic lines of force.”
Second Law of Electromagnetic Induction
measuring device that measures
magnetic flux, ∅ of a magnet system or
a single magnet
Flux Meter
An individual piece of wire placed in the slots of
the DC machine.
Conductor
Formed by looping wires or conductors around
the armature.
Turn
Made when one or more turns of wire (single-turn
coil or multi-turn coil) are placed in an almost
similar magnetic position inside the DC machine.
Coil
A part of the coil in each conductor slot.
Coil Side
A type if winding that Forms a loop as it expands around the
armature core.
Lap Winding
A type if winding that Forms a wave as it expands around the
armature core.
Wave winding
Combination of lap and wave coil windings.
Frog-leg winding
➢ In this winding, the coil ends of each
armature coil (start and end) is
connected to adjacent commutator
segments.
➢ The finishing end of one coil is situated
under the same pair of poles of the
starting end of the next coil.
➢ The number parallel paths and brushes
is equal to the number of poles.
➢ This type of winding is used for high-
current and low-voltage rating
generators.
Lap Winding
➢ In this winding, the coil ends of each
armature coil (start and end) is separated
by the distance between two pairs of
poles.
➢ The finishing end of the one coil is
connected to the starting end of the next
armature coil situated under different
pairs of poles.
➢ The number parallel paths and brushes is
always 2.
➢ This type of winding is used for low-
current and high-voltage rating generators.
Wave winding
