23 July 2013

SELECTIING MOTORS FOR YOUR PROJECTS FROM DIFFERENT MOTOR TYPES



If you want your project to have some form of movements, linking a motor to some mechanism is one effective way of achieving the purpose. Whether it is to rotate a platform, or to swing a door, or to manipulate a lever, a motor can be the power source to operate the mechanism. However, you have to select the correct type of motor to match the job. Using the wrong motor would result in under-performance and in the worse case, the project ending in a complete failure. The following is an introduction to the different types of motor and their applications.

1. DC Motor
   This is the most common type of small battery operated motor that can be used for a variety of projects. The main advantage is their small size and they do not require complicated control. It can be connected directly to the rated battery voltage for simple functions. Straight from the box, a typical DC motor spins in excess of 15,000 rpm (revolution per minute), which is way too fast for most applications. To be useful, it must be geared down to the appropriate speed. Another reason for gearing down a DC Motor is to increase the tuning torque (turning power) which is required to do useful work. 

Applications:
Because of their small sizes and easy control, DC motors find many uses in modern appliances. They can be found cooling power supplies and CPUs in PCs and operating CD ROM drives. Printers use a few of them in each unit to feed paper to the print head. As a result, they can be found easily in used equipment and modified to for use in a project. However, it is important to note that DC motors are not very precise in their operations. Their speed can vary quite a bit even under the same operating condition. This is especially the case when they are under load.

Motor Selection When selecting a DC motor, ask yourself the following questions:

What is the load it is expected to bear? This is the turning torque of the motor and is measured in kg.cm. If the expected load is higher than the motor’s rating, it would heat up very quickly when in use and will soon breakdown. This is a very common cause of motor failure in projects. Always cater for some extra allowance in your selecting the power rating. For example, if your project requires 3kg.cm force, then choose a unit that gives 6kg.cm force. This would prevent motor failure in the event of the mechanism becoming jammed, which is quite common in the development stages.
What speed is the motor expected to turn at? Motor speed is measured in rpm. In applications where the speed is an important factor, it would have to be reduced by a series of gears. Some motors are sold with gear box with user-selectable ratios. These allow the user to select the gear ratio by interchanging the positions of the gears to arrive at a suitable speed for the output shaft. Further speed refinement can be done with an electronic speed controller.

DC Motor Control:

Some kind of control circuit is required if you need the motor to do more than just spinning. An example is when a motor is used to slide a tray open and close. The motor will need to turn in one direction to open the tray and stop. This is followed by turning in the opposite direction to close the tray. The control circuit would have to accept a signal to turn the motor in one direction and reverses it when a second signal is received to close the tray. The example cited above is relatively easy.
It can be accomplished by means of some switches connected together. For more complicated movements, an intelligent controller would be required. These may include movements that return the output shaft to the original position or one that requires several stops in one revolution.

2. AC Motor

   AC motors are complicated electrical equipment. They are mentioned here just so that you know that there is such a type of motor. Unlike DC motors, they cannot be powered by batteries and requires special connections to enable them to work properly. The most commonly available AC motor in small size is the synchronous motor. It spins at a constant rpm and are found in electric clocks (not battery-operated quartz).

Applications

These days, AC motors are found mostly in heavy industries like machine tools and equipment that require continuous operation like the compressor in refrigerators. Invariably, these tend to be large. Occasionally they may be used in places where speed is not an important factor. A new generation of AC (synchronous) motor has found its way into hobby uses. They provide very high speed power for electric model airplanes.
Because of mass production, they have become quite economical although the complicated electronic controllers are still expensive. AC motors are not useful for most projects unless there is a specific requirement.

3. Servo motor

   These are, strictly speaking not designed as motors like in the above categories. Servos were first used as escapement control to move valves
   and levers in mechanical systems. Ocean-going oil tankers make extensive use of servos to transfer crude oil to and from their bulk tanks. They have a built-in DC motor with reduction gears to increase their operating torque. An electronic circuit controls the movement of the motor precisely. All these are housed in a single casing making servo very compact and easy to use. For application in small projects, hobby servo is an ideal source of power.(photo - servos, inside).


Applications

Hobby servos can be used as they are or with modification. Ordinarily, they are the power houses that push and pull the elevators and ailerons of model airplanes. In recent years, they are used in robotic controls. Modified servos were first used as wheel motors because of their compact size, high power and easy control. A pair of continuous turning servos can easily power a 5 kg mobile robot. There are now purpose-made units for robotic applications. These have higher power output and very precise displacement control. Many find applications in moving limbs and sensors. Hobby servos can be linked to levers or cranks to effect useful movements in a project.(photo – door mech, mobile robot, brat).

Servo Selection

As in DC motor, servos come with different power rating. They range from 1.5 to12 kg.cm, varying also in physical size and battery consumption. Servos are more tolerant to overload because of the built-in reduction gears and sometimes current-limiting capability. The end result of using an underpowered servo is a stalled movement, usually without serious damage to the servo. It is still advisable to use a higher power servo motor for any application to cater for friction and mechanical losses due to sloppy linkages. Servo Control Servo can only be controlled by a servo controller designed for the purpose. 

The use of other types of controller can result in a damaged servo. There is a three-wire cable attached to all hobby servos. This cable must be connected to the controller in the right direction. The standard unmodified servo can move its output disc within limits, usually 100 degrees. The disc can be set to move between different angles and external linkages can be attached to the servo output to activate other mechanisms. Modified servos have their internal mechanical stops removed so that the motor can spin without restriction. In this case, the controller only controls the rotational speed. This is usually within a very limited range.

4. Stepper Motor

   Of all the motors considered so far, the stepper motor offers the greatest precision in term of displacement. However, they are inherently slow and bulky (and heavy) for the same power rating. A series of magnetic windings are placed around the casing (stator) at regular interval. Permanent magnets are attached on the rotor (the central spinning part) with no external electrical contact. The rotor therefore is freewheeling. Electric current is passed through the stator windings sequentially to cause the rotor to spin or to displace a specific angle and hold its position. A stepper motor with an appropriate controller can be expensive. You may want to consider the cost effective before deciding on using one.(photo – stepper, small and big).

Applications:

The stepper motor is the motor of choice in controlling the position of print heads in printers and laser sensor in CD ROM drives. These applications require very precise positioning of mechanical parts within a system. Except in the special areas of robotics, stepper motors are not very useful for general project because of their low torque and complicated control set-up.(photo – CD ROM, printer)


Stepper Motor Control

Special electronic controllers are used to control the movement of steppers. Depending on the motor used, the unit angle of displacement, speed and total displacement can be controlled. Steppers have the unique equality of holding a rotor position without damaged.












22 July 2013

MAJOR and MINI PROJECT IDEAS FOR ECE and ELECTRICAL STUDENTS


Process Control, Instrumentation and Fuzzy Logic Projects

  • Power Distribution Management System using WAP
  • Virtual instrumentation for temperature controlled loop
  • Pc based attendance cum visitor management system
  • Micro controller based Boiler Management System
  • Priority Indicators in Alarm Annunciators
  • Multi Channel Voltage Scanner with SCADA
  • Micro controller based Position Control for Stepper Motor
  • PC Based Programmable Temperature Controller for Furnaces
  • PC Based Programmable Temperature Controller for Cement Plant
  • Temperature and Humidity Measurement System for Agricultural Applications
  • Wireless Parameter monitoring on Irrigation systems
  • Micro controller Based Multichannel PID Controller for temperature
  • Micro controller based Dedicated PID Controller for Temperature
  • PC Based Pollution Tester for Vehicles with WEB CAM Interface
  • PC Based Pollution Tester for Vehicles with CO Analyzer
  • Fuzzy logic based DC-DC Converter using 8 bit Microcontroller
  • Application of Fuzzy Logic in intelligent Traffic Control System
  • Automatic Control of Bottle Filling System using PLC with Conveyor Mode
  • Control of Boiler Turbine Unit Based on Fuzzy Logic System
  • Development of man machine interface using SCADA Package
  • Fuzzy logic based Speed Control of AC Motor Using Microcontroller
  • Implementation of Vehicle Collision Avoidance System Using Fuzzy Logic
  •  Ultrasonic based Distance Monitoring and Fuzzy based Collision Avoidance
  • PLC based Automatic Boiler Management
  • Intelligent guided vehicle for collision prevention
  • Fuzzy Logic based Collision Prevention for vehicles
  • Intelligent Application of Fuzzy Logic in Automatic Train Speed Control System
  • Fuzzy logic based Traffic Control System - A Replacement strategy
  • Automatic Temperature Control using Fuzzy Logic
  • Automatic Valve Control using Motors with Fuzzy Logic in Process stations
  • Brightness Control System by Lamp Dim / Bright Illumination inside city areas
  • Automated weigh load cell / Commercial weighing system
  • Automatic anesthesia controller using infusion pump with heart beat rate
  • Automatic Toll Gate Opening / closing with vehicle details logging
  • Batch weighing & automation system using conveyors
  • Fault Identification (Annunciator) using Embedded System
  • Categorized Alarm Annunciator using Embedded System with controls
  • Categorized Alarm Annunciator with Voice using Embedded System with controls
  • Multi-Parameter Measurement System and Control with Graphs
  • Best operating point tracking/Positioning of the solar cell power supply system
  • Smart Solar Tracking System for Optimal Power Generation
  • Solar power for automatic water heating
  • Solar energy for Electrical Applications
  • DAS and Remote Control through Internet
  • SALVO RTOS Based Data Acquisition System and control with PC Interface
  • SUN SAIL - Tracking Elliptical Path Of The Sun
  • Solar Air Heating System
  •  Solar Water Heating System
  • Automated car parking system
  • PC based electronic weighing scale with set point
  • Bluetooth Enabled Advanced Data monitoring and control using Hitech C
  • PLC for bottle filling station with conveyors
  • Embedded System Based Automatic Furnace Control for Improvement Of Hardness On Materials
  • Design of Digital Cryogenic Temperature Controller
  • Micro controller Based Standalone Temperature Measurement System
  • Micro controller Based Ultrasonic Pulse Detector
  • Pc Based Flow Control and Level Measurement in Petrol Bunks
  • Pc as a PID Controller
  • Smart solar tracking for optimal power generation
  • Pc based Wireless Weather monitoring System

21 July 2013

ELECTRICAL ENGINEERING PROJECT TOPICS FOR ENGINEERING STUDENTS-2013


  • Embedded PIC MC based Electronic Trivector Meter
  • Embedded PIC Microcontroller Based Power Multimeter
  • Embedded PIC Microcontroller Based Motor Protection System
  • Energy Management System for Pulse Output Meters
  • AC Power line Monitoring motor generator application
  • Speed Control of AC Motor
  • Speed Control of DC Motor with Field and Armature Control
  • DC Drive using IGBT
  • AC Drive using IGBT
  • Maximum Demand Indicator / Controller for Industries
  • Power Factor Correction Using Multiple Capacitor Banks
  • Electricity Billing Automation
  • Prepaid Electricity Billing Automation
  • Digital Tri Vector Meter
  • Multiple starters with overload protection
  • Multiple starters with overload protection with AI
  • Multiple starters with overload protection with WAP
  • Hybrid SCADA for Power station Substation Monitoring & Automation
  • Embedded System based POSI-CAST controller for Dc-Dc Buck Convertor.
  • Novel ZVT- PWM Converters with active snubbers
  • Active resonant snubbers for high frequency PWM converters
  • A ZVT-PWM Single stage PFC Converter with active snubber
  • Electrical Station Variables Reader/Controller with True Graph and SCADA
  • Electrical Station Variable Reader/Controller with True Graph
  • Remote On/Off Controller for AC Motors with Parameter Monitoring
  • Remote Switching System for home appliances
  • Power Sharing of Transformers with WAP
  • Power Sharing of Transformers with auto protection
  • Computer Keyboard as a dual controller for switching Electrical devices
  • Energy Saving In 1- Phase Induction Motor using A.C Chopper
  • Harmonic Reduction using Capacitor Clamped Multilevel Inverter
  • Harmonic Reduction using Diode Clamped Multilevel Inverter
  • High Frequency Zero Voltage Switching Resonant Converter
  • Integral Cycle Controlled Inverter fed Induction Motor Drive
  • L-Type High Frequency Quasi Resonant Zero Current Switch
  • Micro Controller based Transformer Protection Third Harmonic Auxiliary Commutated Current Source Inverter
  • Thyristor Switched Capacitor scheme for fast changing industrial loads
  • Two input full bridge DC-to-DC converter for selective Harmonic elimination.
  • Two input Full Bridge Inverter with improved output waveform
  • Closed Loop Speed Controller for DC Motor using Microcontroller
  • Design of a Microcontroller-Controlled Personal Static Var Compensator (PSVC)
  • Fuzzy Logic Based Faults Identification System for a Three-Phase Induction Motor PID controller for real time dc motor speed control
  • Sensor field oriented control of 1 phase induction motor using microcontroller
  • Programmable Single Phase Motor Overload Automatic Preventer
  • Speed Control of DC / Induction Motor using PID / Fuzzy Controller
  • Dual control of Electrical devices through Computer Keyboard and H/W
  • Centralized Powerhouse Automation using WAP
  • Slip Ring Induction motor Drive with slip Recovery using IGBT
  • DC motor Starter using MOSFET
  • Microcontroller Based Oil Temp/IND/CON
  • 3 Phase AC Motor Drive using IGBT
  • Two / Four Quadrent chopper in Indian Military
  • Multi Channel Voltage Scanner with SCADA
  • Micro controller based Position Control for Stepper Motor
  • WEB-SCADA
  • Speed Control of AC / DC / induction Motor with RF Technology
  • Electric Power Generation using Footstep Method 
  • Embedded Micro controller based Grid Synchronization 
  • Energy Management Control System with WAP 
  • Home Automation Using X-10 Protocol 
  • Bi Directional VF Control of Single Phase AC Motors 
  • Frequency Actuated Load Shedding with substation monitoring
  • Management of sub-transmission and distribution system in power Systems 
  • Mobile - Half Bridge Configuration Based High Voltage Generation of 10KVA_1KHZ 
  • Vector Controlled Drive for Energy Saving in Air Conditioning system 
  • High Performance AC Supply with Low Harmonic Distortion for multiphase AC Machines 
  • Enhancement of power system performance using STATCOM
  • Management of sub-transmission and distribution system in power 
  • systems
  • Remote data monitoring using WAP Information Gateway
  • Vector Controlled Device For Energy Saving Air Conditioning System
  • Fuzzy Logic Based Differential Relay For Power Transformer Protection 
  • Single Phase to 3 Phase Converter For Driving 3 Phase Motor using Single Phase
  • Embedded System based Automatic Furnace control for improvement of Hardness on materials.
  • Distributed Multi area Power systems load flow monitoring
  • SCADA Based Temperature Measurement & Control System
  • SCADA for instrumentation with Artificial intelligence Control
  • Intelligent Briefcase with digital code lock and shock generator during unauthorized access
  • Digital Timer with Thumbwheel setting with On and Off delay type
  • Digital Counter using Proximity Sensor
  • Digital Energy meter using Embedded Controller
  • Digital Energy meter with voice annunciation
  • Digital RPM Indicator using Proximity or Magnetic Pick up
  • Digital Frequency indicator
  • Digital Voltmeter using Embedded System
  • Digital Ammeter using Embedded System
  • Cyclic Timer using Embedded system
  • Remote Digital RPM Indicator using Proximity or Magnetic Pick up with SCADA




15 July 2013

Simple Count Down Timer Using LCD



                   Countdown Timer Using LCD

A countdown timer is a down counter that counts from a specified time to zero. It is used in many devices such as washing machine, televisions, microwave ovens, etc. This countdown timer has three states: the running state where it counts down, the pause state where it displays the paused time and the reset state to set the countdown.

I have developed this count down timer as part of my another project.This  count down timer count from 99 to zero. This can be used as count down timer in hours or minutes or seconds by adjusting the delay value.For count down in minutes delay value will be 6000.Also the maximum value of count down can be change in program.The reset switch will reset the count down timer.Main parts of the project are microcontroller AT89C51and LCD,5v Regulated power supply.


Microcontroller AT89C51:

Microcontroller AT89C51 is at the heart of the circuit. It is a low power, high performance, 8-bit microcontroller with 4 kB of flash programmable and erasable read-only memory (PEROM) used as on-chip program memory, 128 bytes of RAM used as internal data memory, 32 individually programmable input/output (I/O) lines divided into four 8-bit ports, two 16-bit programmable timers/counters, a five-vector two-level interrupt architecture, on-chip oscillator and clock circuitry. A 11.0592MHz crystal (XTAL1) is used to provide basic clock frequency for the microcontroller. Capacitor C3 and resistor R3 form the power-on reset circuit, while push-to-on switch S20 is used for manual reset.


Liquid Crystal Display (LCD):

Liquid crystal display a type of display used in digital watches and many portable computers.LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

The liquid crystals can be manipulated through an applied electric voltage so that light is allowed to pass or is blocked. By carefully controlling where and what wavelength (color) of light is allowed to pass, the LCD monitor is able to display images. A back light provides LCD monitor’s brightness.Other advances have allowed LCD’s to greatly reduce liquid crystal cell response times. Response time is basically the amount of time it takes for a pixel to “change colors”. In reality response time is the amount of time it takes a liquid crystal cell to go from being active to inactive. Here the LCD is used at both the Transmitter as well as the receiver side. The input which we give to the microcontroller is displayed on the LCD of the transmitter side and the message sent is received at the receiver side which displays at the receiver end of the LCD and the corresponding operation is performed.

They make complicated equipment easier to operate. LCDs come in many shapes and sizes but the most common is the 16 character x 4 line display with no backlight. It requires only 11 connections – eight bits for data (which can be reduced to four if necessary) and three control lines (we have only used two here). It runs off a 5V DC supply and only needs about 1mA of current. The display contrast can be varied by changing the voltage into pin 3 of the display.

 Power Supply Unit

The power supply unit is used to provide constant 5 V dc supply to the peripherals. The 230 V ac is converted into 9 V ac by using a transformer and then a bridge rectifier rectifies it to a 9 V dc with ac ripples. This is then filtered by electrolytic capacitors used across the rectifier output. LM7805 regulator is employed to obtain a constant 5 V dc at the output.

 Count Down Timer Using LCD Program


#include<reg51.h>
#define cmdport P3
#define dataport P2
sbit rs = cmdport^0;  //register select pin
sbit rw = cmdport^1;  // read write pin
sbit e = cmdport^6;  //enable pin
void delay(unsigned int msec)  // Function to provide time delay in msec.
{
int i,j ;
for(i=0;i<msec;i++)
for(j=0;j<1275;j++);
}
void lcdcmd(unsigned char item)  //Function to send command to LCD
{
dataport = item;
rs= 0;
rw=0;
e=1;
delay(1);
e=0;
}
void lcddata(unsigned char disp)  //Function to send data to LCD
{
dataport = disp;
rs= 1;
rw=0;
e=1;
delay(1);
e=0;
}          
void main() 
{  
  while(1)
  {
    unsigned int i,s,test_final;
    lcdcmd(0x38);  // for using 8-bit 2 row mode of LCD
     delay(100);
      lcdcmd(0x0E);  // turn display ON for cursor blinking
       delay(100); 
        lcdcmd(0x80);
                    
                   delay(25);
          for(i=99;i>0;i--)
                     {     
                           lcdcmd(0x01);       
                                test_final=i;               
                  s=test_final/100;
                   test_final=test_final%100;
                   if(s!=0)
                                         {
                   lcddata(s+48);
                                         delay(250);
                                         }
                   else
                                         {                           
                            s=test_final/10;
                            test_final=test_final%10;
                            lcddata(s+48);
                             lcddata(test_final+48);
                            lcddata(0);
                                                                   delay(250);
                                                }                                   
                     }
   }
               
}       


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