Electrical Laws

Ohm's Law Coulomb's Law Kirchoff's Law Faraday's Law Ampere's Law Joule's Law Lenz's Law Biot Savart Law

Electrical Theorems

Thevenin Theorem Nortons Theorem Super Position Theorem Reciprocity Theorem Compensation Theorem Maximum Power Transfer Millmans Theorem Tellegans Theorem

Electrical Rules

Flemings Left Hand Rule Flemings Right Hand Rule Cork Screw Rule

Electrical Network

Network Terminologies

Electrical Terms

Electrical Terms Materials Capacitors Resistors Inductor Self Inductance Mutual Inductance Magnetic Flux Magnetic Characteristics EMF MMF Permeability Sources Reluctance Torque

Electrical Transformer

Transformers How Transformer Works Transformer Classifications Types Transformers Core Type Transformers Ideal Transformers Parallel Operation Transformer Cooling Transformer Forces Transformer Losses Transformer Testing Transformer Bushing Transformer Windings

Types of Transformer

Auto Transformer Current Transformer Potential Transformer Rectifier Transformer Converter Transformer

AC Motor

Stator and Rotor Three Phase Induction Motor Induction Motor Transformer

AC Generator

AC Generators Alternator Stator Construction Alternator Rotor Construction Alternator - Parallel Operation Synchronizing AC Alternator Losses in Alternator

DC Motors

DC Motors Commutator Braking of Electric Motors Dynamic Rheostatic Braking Regenerative Braking Plugging Braking Speed Control DC Motor Losses DC Motors

Types Of DC Motor

DC Motors Types DC Series Motors DC Shunt Motors DC Compound Motor Brushless DC Motors Permanent Magnet DC Motor

Starter For DC Motors

Starters DC Motors

DC Generator

DC Generator Types DC Generators Sparking DC Generators Why Generator Overloading Losses DC Generators

Parallel Operation

PO - DC Generator Series DC Generator Shunt DC Generator Compound DC Generator
The ones who are crazy enough to think they can change the world are the ones who do.
- Steve Jobs
NEXT

Losses in DC Machines

In all machines, the whole of input energy does not get convertered into output energy. A portion of the input energy gets lost in the machine. DC motor is not exceptional in this case.

I2R loss in the armature winding

Every winding consist of resistance, when the current flow in the armature winding some parts of the energy is get lost (Ia2Ra loss) in the form of heat due to resistance in it, where Ia is the armature current and Ra is the resistance of the armature circuit. when load on the machine changes, as a result armature current too change. Thus Ia2Ra is called the variable loss as this loss varies with the variation of load on the motor.

Core loss or Iron loss in the armature

Core loss or iron loss consist of both hysteresis loss and eddy current loss. The core of any electrical device or machine is made of magnetic material like iron and is subjected to variation in magnetic flux. When a DC machine is given with supply, the armature rotates and comes under North poles and South poles alternately. Hysteresis loss occurs due to the alternate magnetization of the magnetic material. Hysteresis loss depends upon

  • Flux density
  • Frequency of variation of flux
  • Volume of core material

On the other hand, eddy current loss is due to the presence of circulating current in the core material. Emf will induced in the armature core when it rotate in the magnetic field. This EMF causes a circulating current in the winding of the armature and dissipated in the form of heat. Eddy current loss depends upon

  • Flux density
  • Frequency of alternation of flux
  • Thickness of laminations used for winding
  • Volume of core material

Loss in the field windings

When the current flow in the field winding, some parts of energy is dissipated in the form of heat as in armature winding. Field winding loss = VIf, where V is the applied voltage and If is the field current.

Friction and windage losses

Due to rotation of the armature, air-friction loss which is also called windage loss, take place. Frictional loss occurs due to brush and commutator rubbing and loss due to bearing friction.

NEXT

Related to Losses in DC Machines

Most visited

Report Us

We may make mistakes(spelling, program bug, typing mistake and etc.), So we have this container to collect mistakes. We highly respect your findings.

Report

Programming

Electrical

Interview

© Copyright 2019