Electric Traction➔It refers to the use of electric power for propelling vehicles, especially Mechanism of Train Movement➔Train movement

in movement is governed by the balance between the Coefficient of Adhesion➔ Advanced traction control systems help maximize adhesion by
railway trains, trams, and trolley buses. It has become widely popular due to its efficiency, tractive effort (force exerted by the train to move) and the resisting forces (forces opposing modulating torque based on rail conditions.The coefficient of adhesion (μ) is the ratio of the
cleanliness, and reliability. An ideal traction system should meet several technical and motion). The total tractive effort must be sufficient to overcome all resistances and achieve the maximum usable tractive effort to the adhesive weight (weight on the driven axles):--
operational requirements to ensure smooth, safe, and economical transportation. desired speed and acceleration. μ=Maximum Tractive Effort/Adhesive Weight⋅g ///Where:--μ = Coefficient of adhesion
Requirement ➔1.High Starting Torque-An ideal traction system must provide a high starting 1. Energy Consumption➔Energy is consumed mainly during:-Acceleration//Overcoming (unitless)//g = Acceleration due to gravity (9.81 m/s²)///Importance:--Limits the maximum
torque to overcome the inertia of stationary vehicles. This is essential for heavy loads like trains resistance (rolling, air, mechanical)//Climbing gradients.///Total energy consumption (E) tractive effort without wheel slip.//Influences design of drive systems, motor torque control,
and trams that need significant force to initiate movement.//2.Smooth Acceleration and depends on:--Train mass (m)//Distance (d)//Acceleration and deceleration patterns//Efficiency and braking systems.//Affects acceleration capability and hill-climbing performance.
Braking-Gradual acceleration and deceleration are critical to ensure passenger comfort and of motors and drive systems.//Energy is generally supplied in the form of electricity and Motor Control in Electric Traction➔Multiple motors are used to drive the axles of electric
reduce mechanical stress on the traction system. The ability to control the speed accurately and measured in kWh. Regenerative braking can recover part of the energy during deceleration. locomotives. These can be connected in:-- Series Operation:-Motors connected end-to-
apply smooth regenerative or dynamic braking is desirable.//3.Reliability and Availability- 2. Tractive Effort During Acceleration➔To accelerate a train, tractive effort must overcome end//Same current flows through all motors//Voltage divides between motors.//Application:-
The system must be highly reliable and have minimal downtime. This includes durable inertia. The force required is:--Fa=m⋅a Low-speed conditions or starting phase where torque demand is high.///Parallel Operation:-
components, low maintenance requirements, and the ability to operate under various Where:--Fa= Tractive effort for acceleration (N)//m = Mass of train (kg)//a = Acceleration Each motor is fed with the same voltage//Currents divide according to load.//Application:
environmental conditions.//4.High Adhesion and Tractive Effort-The system should ensure (m/s²) Higher-speed operation, better control over each motor.
high adhesion between wheels and rails, especially under adverse conditions like rain or snow, This component is dominant during the starting phase of the train. Equal Wheel Diameter➔All driving wheels have the same diameter//Motors in series or
to prevent wheel slipping and ensure safety. 3. Tractive Effort on a Gradient➔When a train moves on an incline, additional effort is parallel operate synchronously//Load is equally shared//Efficient and balanced operation
Supply system for electric traction➔It refers to the method and infrastructure used to provide needed to counter gravity:--Fg=m⋅g⋅sin(θ) Unequal Wheel Diameter➔Common due to uneven wear and tear over time//Causes unequal
electrical power to railway locomotives, trams, or metro systems for propulsion. This system is For small angles, sin(θ)≈tan(θ)=gradient/100, so:➔Fg≈m⋅g⋅(gradient/100) mechanical speeds for each motor axle (since speed ∝ wheel radius)
a crucial component in electric rail transport and varies depending on the country, type of Where:--Fg= Tractive effort for gradient (N)//g = Acceleration due to gravity (9.81 Effects in Series Connection:-All motors receive same current but rotate at different
railway service, and power requirements. m/s²)//Gradient is usually given as %, e.g., 1 in 100//This component is zero on level tracks but speeds//One motor may overspeed while another lags, causing unbalanced torque//Can lead to
Types:- 1. Direct Current (DC) Systems:--Voltages commonly used: 600V, 750V, 1.5kV, significant on slopes. mechanical stress and overheating///Effects in Parallel Connection:-Each motor receives
3kV.//Applications: Urban and suburban transport like trams, metro systems, and short- 4. Tractive Effort for Resistance➔Several resistances oppose motion:-Rolling Resistance same voltage//Motors draw different currents due to speed difference//Can cause uneven
distance trains.//Advantages: Simple control systems, better torque characteristics for frequent (Rr): Due to deformation of wheels and track.//Air Resistance (Ra): Increases with square of loading, energy wastage, or motor damage
starts and stops.//Disadvantages: Requires more substations due to higher transmission losses; speed.//Mechanical Resistance (Rm): Due to internal friction in bearings, motors, etc.///Total Effect of Sudden Change in Supply Voltage➔Electric traction systems rely on a stable
limited to short distances.///2. Alternating Current (AC) Systems:--Voltages commonly used: resistance (R) is typically estimated using empirical formulas such as the Davis Equation:- voltage supply to maintain smooth train operation. A sudden change (spike or drop) in voltage
15kV, 25kV (single-phase, 50Hz or 16⅔ Hz in some European countries).--Applications: Long- R=A+Bv+Cv2 /// Where:--v = Speed (km/h)//A = Constant rolling resistance//Bv = Bearing can cause serious performance issues:--Voltage Drop:-Reduced motor torque: Since in DC
distance mainline railways.//Advantages: Lower transmission losses, fewer substations, and mechanical resistance//Cv^2 = Air resistance series motors, torque ∝ (voltage × current), a drop in voltage reduces current and torque.//Speed
economical for long-distance travel.//Disadvantages: Requires complex traction equipment Total Tractive Effort (F_total):➔Ftotal=Fa+Fg+R///This total must be provided by the reduction and sluggish acceleration.//May cause stalling or overheating if motors try to maintain
(transformers, converters) on board. traction motors to ensure smooth operation and adherence to the schedule. speed by drawing more current.///Voltage Surge:-Motors may run at higher speed, risking
Speed-Time Curve➔A speed-time curve is a graph representing the variation of train speed Power Output➔Power is the rate at which work is done or energy is transferred to the driving overspeed damage.//Increased torque could lead to wheel slip, especially on low-adhesion
with respect to time during a journey between two stations. It provides a clear picture of how a wheels (axles). For traction purposes:--Power (P)=F⋅v ///Where:--P = Power (watts or kW)//F tracks.//Could damage insulation and components.//Protective relays and automatic voltage
train accelerates, runs at constant speed, coasts, and brakes. The curve consists of several = Tractive effort (Newtons)//v = Velocity (m/s)///This is the mechanical power output at the regulators are used in modern systems to mitigate these effects.
phases:-Acceleration Period: The train starts from rest and gains speed.///Constant Speed driving axles, provided by the electric motors. Temporary Interruption of Supply➔A temporary interruption means the supply is cut off
(Free Running): The train runs at uniform speed.///Coasting: Power is cut off; the train slows Energy Output➔Energy is the total work done over time:--Energy (E)=P⋅t ///Measured in briefly (seconds to minutes) due to faults, switchovers, or power failure.
down gradually due to resistance.///Braking: The train is decelerated using brakes until it comes kWh, this energy represents the output delivered by the motors to move the train over a given Effects:-Immediate loss of propulsion: Motors stop developing torque.//Loss of braking: In
to rest at the next station.//Speed-time curves help in designing traction systems, calculating distance/time. electric braking systems like regenerative or dynamic braking, braking force disappears.//Can
energy consumption, and planning schedules. Specific Energy Consumption (SEC)➔ is the energy used per unit weight per unit distance:- lead to passenger discomfort or safety hazards, especially on gradients or in tunnels.//System
Simplified Speed-Time Curve➔A simplified speed-time curve approximates the real curve SEC=Energy consumed (kWh)/Train weight (tonnes)×Distance (km)///Influencing Factors:- reboot may be required if onboard controls reset.///Mitigation:-Battery backup systems for
using straight lines and is easier for calculations. It generally includes:-A straight-line Acceleration and Deceleration:-More frequent starts/stops increase energy usage.//Use of critical controls//Automatic restarting circuits//Some high-speed trains use dual power or
acceleration from rest to average speed.//Constant speed segment (if any).//A straight-line regenerative braking reduces net energy consumption.///Speed Profile:-Higher speeds increase energy storage to handle brief outages
deceleration to stop.//This approximation simplifies energy and time analysis while still giving aerodynamic drag exponentially.//Coasting and smooth speed transitions help lower Tractive Effort (TE)➔The force that a locomotive exerts on the rails to pull the train.
practical insights into train performance. SEC.///Gradient of the Track:-Uphill sections demand more power.//Downhill movement can TE=P×1000/v///Where:--TE= Tractive effort (Newtons)//P = Power (kW)//v = Speed (m/s)
Average Speed➔Average Speed =Total distance travelled ÷ Total time taken allow for regenerative energy recovery.///Track Conditions:-Curves and poor rail conditions It’s critical for starting, acceleration, and climbing gradients.///Typical ranges:-Shunting
(excluding stops).//It reflects the actual performance of the train while it's in motion. It's increase rolling resistance.///Train Load:-Heavier trains require more energy, though SEC locomotives: High TE at low speed//Express trains: Lower TE at high speed
influenced by acceleration, deceleration, and speed limits. might reduce due to better load distribution.///Driving Technique & Automation:-Skilled Horsepower (HP)➔1 HP=746 //It is another measure of power, often used in older systems or
Schedule Speed➔Schedule Speed =Total distance travelled ÷ Total time including stops. driving or automated train operation (ATO) systems optimize acceleration and braking, countries like the USA. Power can also be expressed in kilowatts (kW) or megawatts (MW) in
It is less than the average speed, since it includes dwell time at stations. It is a key parameter in improving SEC.///Maintenance Condition:-Poorly maintained bearings, wheels, or motors modern systems.///Power (kW)=TE⋅v/1000//This shows that tractive effort and horsepower are
timetable planning and passenger service efficiency. increase resistance and energy waste. interdependent based on speed.

AC Series Motor for Traction➔Working Principle:-The AC series motor is essentially a Current Collection in Traction Systems➔ Lighting Requirements➔Effective lighting design considers:-Visual comfort (low glare)//
modified version of the DC series motor, adapted to run on single-phase AC. Both the field and Purpose:-To transfer electric power from the supply system (e.g., overhead lines or third rail) Task efficiency (adequate brightness)//Safety (especially in work areas)//Aesthetic appeal
armature windings are connected in series. It operates on the principle that reversing both to the train's onboard equipment efficiently and safely. (interior design harmony)//Energy efficiency (LEDs, controls)
current and magnetic field simultaneously preserves the direction of torque.///Features:-High Types➔(i)Overhead Line System (OHE):-Used in AC and high-speed DC systems//Uses Influencing Factors:-Nature of activity (reading, assembly work, etc.)//Background luminance
starting torque//Speed decreases with increase in load//Similar characteristics to DC series pantograph mounted on the train roof to contact the overhead catenary wire //Uniformity of illumination//Maintenance and longevity//Daylight integration
motor. (ii)Third Rail System:-Common in urban metro or suburban systems//A metallic rail (third
Use in Traction:-AC series motors were widely used in early AC electric locomotives, rail) mounted beside or between tracks carries current//Contact shoe on the train slides over the Illumination Levels➔Measured in lux, the required illumination levels vary by application:-
especially in countries using single-phase 16.7 or 25 Hz AC systems.//Advantages:-Excellent third rail///(iii) Fourth Rail System:-Used in some systems like London Underground// Application Recommended Lux
for starting heavy trains//Simple and robust design//Direct connection to overhead single-phase Separate rail for current supply and return (reduces return current in running rails) General home lighting 100 – 300 lux
supply possible.//Disadvantages:-Requires commutator and brushes, which need Considerations:-Reliable contact to minimize arcing and voltage drop//Weatherproofing in
Office work (writing, reading) 300 – 500 lux
maintenance//Poor power factor//Performance varies with frequency.//Less efficient compared outdoor systems//Wear and maintenance of contact surfaces
to modern motors. Power Electronic Controllers in Traction System➔ Precision assembly work 1000 – 1500 lux
Control Methods➔ Rheostatic Control (Manual/Resistance Control):-External resistances Role:-Power electronics are used to control, convert, and regulate electric power supplied to Hospital operating rooms 1000 – 2000 lux
are added in series with the motor during starting.//As speed increases, resistances are gradually the traction motors, replacing bulky mechanical or resistive systems. Corridors and stairways 100 – 150 lux
cut out.// Energy wasted as heat in resistors; inefficient.///Series-Parallel Control:-Motors are Common Power Electronic Devices:- Street lighting (urban areas) 5 – 20 lux
first connected in series (low voltage, high torque) for starting.//Later switched to parallel (full Device Function Lamp Selection➔Selecting the right lamp (light source) is vital for optimal illumination,
voltage to each motor) for higher speeds.//Common in older locomotives.///Field Control Rectifiers Convert AC to DC (for DC motor systems) energy efficiency, and user comfort. It depends on several factors:
(Field Weakening):-After full speed, field current is reduced to increase speed beyond base Inverters Convert DC to AC (for AC motor systems)
speed.//Reduces torque but increases speed.///Chopper Control (Modern):-Uses high-speed Factors in Lamp Selection➔
Choppers Control DC voltage to motors
switching (semiconductors) to control voltage.//High efficiency and smooth control. Factor Details
Thyristors / IGBTs Act as high-speed electronic switches
Multiple Unit (MU) Control➔MU control allows simultaneous operation of multiple
VFD Controls AC motor speed by varying frequency and voltage Type of Application Indoor (home, office), Outdoor (street, stadium), Industrial, Decorative
locomotives or motor coaches from a single driver's cab.///Features:-Used in EMUs (Electric
Multiple Units), metro trains, and some freight locomotives.//All traction motors in different Applications in Traction:-Smooth speed control of motors (acceleration & deceleration)// Luminous Efficacy Higher lm/W = More efficient (e.g., LED > CFL > Incandescent)
units respond uniformly to throttle and brake commands.///Advantages:-Flexible train Regenerative braking: feeding energy back to the grid//Automatic power factor correction// Lamp Life Longer life reduces maintenance costs (LEDs: ~25,000–50,000 hours)
length//Faster acceleration (motors distributed along train)//Easier handling and control. Improved efficiency and reduced energy consumption///Advantages:-Compact and lightweight Measured in Kelvin (K) — Warm white (2700K), Cool white (4000–
Colour Temperature
Braking of Electric Motors➔Electric braking is used to slow down trains without relying systems//High reliability and low maintenance//Precision control and energy savings// 5000K), Daylight (6500K)
solely on mechanical brakes, improving efficiency and safety. Electric Lighting➔Electric lighting is the art and science of illuminating spaces using electric- Colour Rendering Index Closer to 100 = Better color accuracy (important in retail, design)
Types ➔(i)Regenerative Braking:-Motor acts as a generator.//Converts kinetic energy into powered light sources to ensure visibility, safety, comfort, and efficiency in homes, industries, Initial and Maintenance
streets, and public places. LED lamps are costlier initially but cheaper in long term
electrical energy and returns it to the supply system.//Energy-saving and commonly used in Cost
modern AC/induction systems.///(ii) Dynamic Braking:-Motor acts as a generator, but Key Terms:-Luminous Flux (Φ): Total amount of light emitted by a source, measured in lumens Dimming Capability Needed for mood lighting or energy savings
generated energy is dissipated as heat in onboard resistors.//Used when regenerative braking (lm).//Luminous Intensity (I): Luminous flux per unit solid angle, measured in candela (cd).// Start-up Time Instant (LEDs, Incandescent), Delayed (Mercury, Sodium Vapor)
isn’t possible (e.g., no load on the line).///(iii) Plugging (Reverse Current Braking):-Motor Illuminance (E): Luminous flux falling on a surface per unit area, measured in lux (lx). Environmental Impact Prefer mercury-free and recyclable options (LEDs are eco-friendly)
connections reversed while running → Produces braking torque.//Effective but causes high 1 lux=1 lumen/m2.//Luminance (L): Brightness perceived by the human eye, measured in
current → Used only in emergencies or low-speed applications.///Advantages:-Reduced wear cd/m².//Efficacy: Efficiency of a light source, expressed in lumens per watt (lm/W).//Glare:
Common Types of Lamps➔
on mechanical brakes//Better control, especially on long descents//Can work in combination Discomfort or reduced visibility due to excessive brightness or contrast.
Laws of Illumination➔(i)Inverse Square Law:-The illuminance on a surface is inversely Lamp Type Advantages Disadvantages
with air or disc brakes (blended braking).
proportional to the square of the distance from the light source:- E=I/d2.// Incandescent Cheap, good color rendering Inefficient, short lifespan
Electrolysis Due to Current Through Earth➔
What Is It➔In electric traction systems, particularly DC traction, some return current flows Where:-E = Illuminance (lux)//I = Luminous intensity (cd)//d = Distance from source (m) Fluorescent Efficient, good for offices Contains mercury, flicker, warm-up time
through the earth or metallic structures like rails, pipes, or foundations. This can lead to (ii)Lambert’s Cosine Law:-Illuminance on a surface is directly proportional to the cosine of CFL Compact, efficient Contains mercury, shorter life than LED
electrolysis, a chemical reaction causing corrosion of underground metallic installations. the angle (θ) between the direction of light and the normal to the surface: Highly efficient, long life, instant
LED Higher upfront cost
How It Happens:-Return current ideally flows through rails back to the substation.//However, E=I⋅cosθ/d2 on
due to imperfect insulation, some current leaks into the earth.//This current can dissociate Luminaries➔ luminaire (lighting fixture) is the complete unit consisting of Light source (e.g., Halogen Bright, compact Heat generation, shorter life
metallic ions from structures like water pipes, cable sheaths, or reinforcing steel, leading to lamp or LED)//Reflector/diffuser for directing or scattering light//Housing for mounting and HID (Sodium, Metal Very bright (used for streets,
protection//Ballasts/drivers (for discharge lamps or LEDs) Poor CRI, slow startup, specialized uses
corrosion.///Consequences:-Damage to underground infrastructure//Structural weakening of Halide) stadiums)
bridges or tunnel linings//Safety risks and high maintenance costs.//Mitigation Measures:-Use Types➔(i)Direct: Projects >90% of light downward (e.g., downlights)//(ii)Indirect: Reflects
of electrically insulated rail joints//Impressed current cathodic protection (ICCP) light off ceilings/walls//(iii)Diffused: Uses translucent materials to spread light evenly
systems//Installing dedicated return conductors or booster transformers.
Lamp Maintenance➔Maintaining lighting systems ensures efficiency, safety, and reliability. LED (Light Emitting Diode) Displays➔LEDs emit light when current passes through a (ii)Occupancy Sensors (Motion Detectors):-Function: Detect human presence and control
It involves both preventive and corrective actions. semiconductor material.Common in billboards, digital signages, scoreboards, and outdoor lights accordingly.//Technologies:-PIR (Passive Infrared) – detects heat movement,Ultrasonic
Routine Maintenance Tasks:-(i)Cleaning Fixtures and Lenses:-Dust and dirt reduce light video walls.// Features:-Brightness: Excellent for outdoor use, even in sunlight.//Energy- – detects sound reflections,Dual Technology – combines both for accuracy//Usage: Offices,
output by 20–30%.//Clean regularly with non-abrasive materials..///(ii)Lamp Replacement:- efficient: High lumens per watt.//Color Capability: Full RGB (Red, Green, Blue) for vivid restrooms, corridors, conference rooms//Benefits: Prevents lights being left on in unoccupied
Replace burned-out lamps promptly.//In critical areas, use group replacement for uniform light visuals.//Long Life: ~50,000+ hours.//Applications: Advertising, public information systems, spaces
output.///(iii)Checking Electrical Connections:-Loose or corroded terminals can cause dashboards. Controller Desig➔Lighting controllers are the brain of smart lighting systems, integrating
flickering or failures.///(iv)Inspection of Ballasts/Drivers:-Fluorescent and LED systems use LCD (Liquid Crystal Display)➔Uses liquid crystals and a backlight (often LED) to display sensor inputs with control logic to optimize performance.
ballasts/drivers which may fail over time.//Replace faulty units to avoid premature lamp images.Suitable for indoor and close-range applications: laptops, control panels, medical Design Features:-
failure.///(v)Monitoring Performance:-Use light meters to check lux levels.//Identify areas equipment.//Features:-High resolution and clarity.//Better for detailed images and text.//Lower Component Function
with degraded illumination for revamping.///(vi)Thermal Management:-Ensure heat sinks or brightness than direct-view LEDs.//Applications: Digital meters, control room screens, CCTV Microcontroller/PLC Core logic processor
ventilation for LEDs are working to prevent overheating. monitors. Sensor Interfaces Inputs from daylight/occupancy sensors
Lighting Schemes➔Lighting schemes refer to the arrangement and distribution of light Beacons➔Beacons are high-visibility warning or signal lights, often flashing or rotating, used
Dimming/Relay Drivers Output to lighting circuits (PWM or switching)
sources to achieve uniform, efficient, and visually comfortable illumination. for:-Emergency signalling//Hazard indication//Aircraft, marine, and railway safety
Common Lighting Schemes:- Types➔ User Interface (UI) Manual overrides, scheduling, touch panels
Scheme Description Type Description Communication Modules IoT/Wi-Fi/Bluetooth/KNX for smart integration
Direct Lighting >90% light directed downward (e.g., factories, workshops) Rotating Beacon Uses motors to rotate light (traditional use) Failsafe Modes Ensure basic lighting under sensor/controller failure
Indirect Lighting >90% light reflected off ceiling (e.g., lobbies, art galleries) Strobe Beacon Intense flashes of light (modern use) Common Control Strategies:-Time-based Scheduling: Lights on/off at preset times//Task
LED Beacon Most energy-efficient, long life, low maintenance
Tuning: Adjust brightness for specific tasks or zones//Personal Control: Users adjust lights via
Semi-direct 60–90% down, rest upward (e.g., classrooms)
apps/switches//Load Shedding: Lights dimmed in response to energy demand
Semi-indirect 60–90% up, rest down (e.g., offices) Applications:-Fire alarms, ambulances, police vehicles//Industrial zones (machine faults)//
Benefits of Lighting Controls & Codes:-
General Diffused Uniform diffusion in all directions (e.g., residential rooms) Aircraft warning lights on tall buildings
Lighting for Surveillance➔To provide adequate illumination for security cameras to Aspect Benefit
Lighting Calculations➔Used to determine the number and type of lamps needed for sufficient Energy Savings 20–50% typical lighting energy reduction
capture clear footage under all lighting conditions.
lighting. The Lumen Method is commonly used for general lighting design.
Types➔(i)White Light (LED Floods):-Broad-spectrum visible light.//Pros: Color footage, Operational Efficiency Less maintenance, longer lamp life
Lumen Method Formula:-Total Lumens Required=E×ACU×MF
visible deterrence.Cons: Can cause glare or overexposure.///(ii)Infrared (IR) LEDs:-Invisible Environmental Impact Lower carbon footprint
Where:-E = Illumination level (lux)//A = Area (m²)//CU = Coefficient of Utilization (depends
to the human eye but visible to IR-enabled cameras.//Pros: Covert surveillance at night.//Cons: User Comfort Adaptive lighting improves productivity and comfort
on room shape and reflectance)//MF = Maintenance Factor (accounts for aging, dirt, etc.)
Only monochrome footage.///(iii)Motion-Activated Lights:-Saves energy.//Startles intruders Electric heating➔ is a process in which electrical energy is converted into heat energy. It is
Interior Lighting Design=➔(i)Industrial/Factory Lighting:-High illuminance (300–750
and focuses camera attention.///(iv)Low-light Illumination (Near-IR and Low-lux Lighting): widely used in domestic, commercial, and industrial applications due to its convenience and
lux) for safety and efficiency//Use LED high bays, fluorescent tubes//Uniform lighting with
For environments where constant lighting isn't feasible.//Works with low-light cameras or efficiency. Electric heating offers a range of benefits such as cleanliness, efficiency, safety, and
minimal glare and shadows//Dust- and moisture-resistant fixtures (IP-rated)
image intensifiers. ease of use, making it a preferred choice in many applications.
(ii)Residential Lighting:-Emphasis on comfort and aesthetics//Use a mix of ambient, task, and
Energy Conservation Codes for Lighting➔To promote efficient energy use in lighting Advantages:-Clean and Pollution-Free -No smoke, ash, or harmful gases are produced.
accent lighting//Color temperature: 2700–3000K (warm white)//Common luminaires: LEDs,
systems through regulations, design practices, and controls. High Efficiency -Almost 100% of electrical energy is converted into heat.//Precise Temp.
pendant lights, recessed fixtures
Key Standards & Codes (India):-ECBC (Energy Conservation Building Code) – by Bureau Control -Accurate temperature regulation with thermostats and sensors.//Safety-No risk of fuel
Exterior Lighting Design➔(i)Flood Lighting:-High-intensity lights used for large areas
of Energy Efficiency (BEE).//National Building Code (NBC) – lighting guidelines for various leakage, explosion, or toxic fumes.//Low Maintenance-Fewer moving parts and no combustion
(stadiums, building facades)//Uses metal halide, LED floodlights//Needs proper aiming and
building types.//LEED/BEE Star Ratings – for energy-efficient buildings means less wear and tear.//Silent Operation-No noise during operation.
shielding to prevent light pollution.///(ii)Street Lighting:-Ensures visibility and safety for
ECBC Lighting Provisions➔Lighting Power Density (LPD): Maximum allowable watts per Heating Methods ➔Electrical heating methods convert electrical energy into heat for various
pedestrians and vehicles//Spacing and pole height optimized for uniformity//Typically uses
square meter for different building zones.-Offices: ~10 W/m²//Retail: ~15–20 W/m² applications. The main types include:- (i)Resistance Heating-Heat is generated due to the
LEDs or high-pressure sodium lamps//Standard illuminance: 10–20 lux for city streets
Use of efficient light sources: LEDs preferred over CFLs, halogens//Mandatory lighting resistance offered by a material to the flow of electric current.//(ii)Induction Heating-Uses
Lighting for Displays & Signaling➔(i)Neon Signs:-Gas-discharge lamps that glow when
controls: Integration of daylight & occupancy sensors//Daylight zone requirements: Lights in electromagnetic induction to heat conductive materials.//(iii)Dielectric Heating-Also known
high voltage is applied//Used in advertisements, signage, decorative displays//Durable and
daylight zones must be automatically dimmed or switched off when natural light is sufficient. as high-frequency or radio-frequency heating, used for non-conductive materials.//(iv)Arc
visible even in daylight//Available in various colors and shapes.///(ii)Display Lighting:-
Lighting Controls➔Lighting controls automate and optimize the use of light based on Heating-Heat is produced by an electric arc between electrodes; used in electric arc furnaces.
Highlights merchandise or art in retail/museum environments////Uses track lighting, spotlights,
occupancy, daylight, time schedules, and user preferences. (v)Infrared Heating-Uses infrared radiation to heat the surface of materials; common in drying
and LED strips//Adjustable and directional fixtures for focused impact.///(iii)Signal Lighting:-
(i)Daylight Sensors (Photocells);-Function: Detect ambient natural light levels.//Working: and curing processes.
Traffic lights, indicators, and warning lights//Must be high-contrast, fail-safe, and color-
Adjust or turn off electric lights when daylight is adequate.//Applications: Near windows,
coded//Uses LEDs for reliability and brightness
skylights, atriums.///Types:Open-loop: Measures outdoor light only.//Closed-loop: Measures
total light (natural + artificial) in space

Resistance heating ➔is the process of generating heat by passing an electric current through Thermostat Control Circuit➔A thermostat is a device that automatically regulates Arc Furnace➔Construction:-Shell:Steel outer shell lined with refractory material.//
a material that offers resistance to the flow of current. The electrical energy is converted into temperature by switching the heating element ON or OFF. Electrodes:-Usually graphite electrodes inserted through the roof.//In direct arc: electrodes
heat energy according to Joule’s Law. Working Principle:-Most domestic thermostats use a bimetallic strip that bends with contact the charge.//In indirect arc: electrodes form an arc above the charge.//Hinged Roof:-
Direct Resistance Heating➔How it works:-Electric current flows directly through the temperature.When the desired temperature is reached, the strip bends and opens the circuit, Allows charging of scrap or raw material.//Tilting Mechanism:-For pouring molten metal after
material to be heated.//Heat generation//Heat is developed within the material itself due to its cutting off the current.As the appliance cools, the strip returns to its original position and melting.//Power Supply:-Usually three-phase AC, connected to a transformer.
electrical resistance.Examples:-Electric arc furnaces//Resistance welding//Salt bath heating. reconnects the circuit, restarting the heating. Working Principle:-Electric current passes through the electrodes.An arc is struck, generating
Use:-Suitable for conductive materials needing quick and direct heating. Components:-Sensor//Control knob/dial//Switching mechanism (relay/contact) intense heat.The charge melts due to arc heat.Temperature is controlled by adjusting arc length
Indirect Resistance Heating➔How it works:-Electric current passes through a separate Applications:-Used in water heaters, ovens, refrigerators, irons, etc., to prevent overheating and power input.After melting, the furnace is tilted to pour out the molten metal.
heating element (like a coil or rod). The heat generated is then transferred to the material.//Heat and maintain consistent temperature. Applications:-Steel manufacturing (Electric Arc Furnace – EAF).//Melting non-ferrous metals
generation:-Occurs in the resistor, and is transferred by conduction, convection, or radiation. Induction Heating➔Induction heating is a non-contact heating process that uses like copper, aluminum.//Scrap metal recycling.//Production of special alloy steels and
Examples:-Electric ovens//Immersion water heaters//Domestic irons and toasters. electromagnetic induction to heat electrically conductive materials. ferroalloys.//Foundries and metallurgical industries.
Use:-Ideal for heating non-conductive materials or when direct contact with current is not Principle:-Based on Faraday’s Law of Electromagnetic Induction.When an alternating current Dielectric Heating➔Dielectric heating (also called radio-frequency or capacitive heating) is a
desired. (AC) flows through a coil, it produces a changing magnetic field.This magnetic field induces process where non-conductive (insulating) materials are heated using high-frequency
Electric Ovens➔Electric ovens are devices that use resistance heating to generate heat for eddy currents in the conductive material placed within the coil.These eddy currents produce alternating electric fields.
baking, drying, or heat treatment in domestic or industrial settings. resistive (I²R) heating, which heats the material internally. Principle:-When a high-frequency AC voltage (typically 10 kHz to 100 MHz) is applied across
Temperature Range:-Domestic ovens:- ~ 100°C to 300°C//Laboratory/Industrial ovens:- Types➔1.Core-Type Induction Furnace➔ a non-conductive material placed between two electrodes, the polar molecules of the material
~ 300°C to 1200°C, depending on design//High-temperature furnaces (specialized):- Construction:-Has a magnetic core (usually laminated iron) around which the coil is wound. oscillate rapidly.This molecular friction generates internal heat uniformly throughout the
~ Up to 1700°C///Applications:-Cooking and baking (domestic use)//Heat treatment of The metal to be heated forms a closed loop (similar to a transformer secondary winding). material.
metals//Drying and curing of paints, ceramics, etc.//Laboratory experiments Working Principle:-Functions like a transformer, where the primary coil carries AC and Applications in Various Industrial Fields➔
Properties of Resistance Heating Elements➔Resistance heating elements are materials used induces current in the metallic charge.Eddy currents flow in a closed loop of the charge, 1.Textile Industry-Drying of synthetic yarn, fabrics, and threads.//Pre-shrinking of
in electric ovens and heaters to generate heat. The ideal heating element must have the following producing heat due to resistance.///Characteristics:-Efficient for low-frequency operation cloth.//Bonding of synthetic fibers.///2.Plastic and Rubber Industry-Welding and sealing of
properties:-(i)High Electrical Resistivity-Ensures greater heat generation for a given current. (e.g., 50 Hz).//Suitable for ferrous metals like steel and iron.//Used mainly for melting and plastic sheets (e.g., PVC, polyethylene).//Molding and forming of thermoplastics.//Curing of
Example materials: Nichrome, Kanthal.//(ii)High Melting Point-Should withstand high heating scrap metal.///Limitations:-Only suitable for metals that can form a closed magnetic rubber products like belts and hoses.///3.Wood Industry-Gluing and bonding of plywood and
temperatures without melting.//Required especially in industrial and high-temperature ovens.// loop.//Not ideal for high-frequency or non-magnetic materials. veneers.//Drying of timber and laminated boards.//Used in furniture manufacturing for fast
/(iii)Mechanical Strength at High Temperatures-Should not deform or break when heated 2.Coreless Induction Furnace➔Construction:-No iron core; consists of a crucible adhesive setting.///4.Food Industry-Pasteurization and sterilization without affecting taste.//
for long periods.//(iv)Low Temperature Coefficient of Resistance-Resistance should not surrounded by a copper coil.The crucible holds the metal charge to be heated. Dehydration of fruits, vegetables, and grains.//Baking and tempering of frozen food.//
change significantly with temperature changes.//Ensures consistent performance.//(v)Long Working Principle:-An AC current in the coil creates a rapidly changing magnetic field, which 5.Medical and Pharmaceutical Industry-Sterilization of medical tools and packaging.//
Life and Reliability-Should withstand multiple heating and cooling cycles without induces eddy currents directly in the metal.These eddy currents cause the metal to heat and Drying of pharmaceutical powders and tablets.6.Electronic Industry-Preheating of electronic
degradation. eventually melt.///Characteristics:-Operates at higher frequencies (typically several components for soldering.//Bonding of circuit boards.
Common Materials for Heating Elements➔Nichrome (Ni-Cr alloy): Widely used in kHz).//Provides uniform heating and stirring due to magnetic forces.//Suitable for both ferrous Infra-Red (IR) Heating➔Infra-red heating uses electromagnetic radiation in the infra-red
domestic appliances.//Kanthal (Fe-Cr-Al alloy): Suitable for higher temperatures.//Silicon and non-ferrous metals (e.g., aluminum, copper, brass)///Applications:-Widely used in spectrum (0.75 to 1000 μm) to transfer heat without direct contact.
Carbide & Molybdenum Disilicide: Used in high-temp industrial furnaces. foundries, metal casting, and alloy production. Principle:-IR heaters emit radiation that is absorbed by the surface of the object, converting
Domestic Water Heaters➔A domestic water heater is an appliance that uses electric resistance Electric Arc Heating➔Electric arc heating is a process in which heat is generated by an light energy to heat.Works similarly to how the sun heats the earth.
heating to raise the temperature of water for household use. electric arc struck between two electrodes, or between an electrode and the charge (material to Applications:-Paint drying in automobiles and furniture.//Plastic thermoforming and sealing.//
Types:-(i)Storage Water Heaters (Geysers):-Heats and stores water in an insulated tank.// be heated).The arc produces intense heat (~3000–3500°C), sufficient to melt metals. Textile drying and printing.//Baking and grilling in food processing.//Medical therapy for pain
Typical capacity: 10–25 liters.//(ii)Instant Water Heaters:-Heats water instantly without Types➔1.Direct Arc Heating:- relief and muscle relaxation.//Curing of coatings, inks, and adhesives.
storage.//Compact and energy-efficient for small usage. Principle:-The arc is struck directly between the electrode and the charge (metal).//Heat Microwave Heating➔Microwave heating uses electromagnetic waves in the frequency range
Temperature Range:-Typically 40°C to 75°C, depending on the setting. Transfer:-Heat is produced within the charge.///Features:-More efficient heat transfer.//Used of 300 MHz to 300 GHz to heat materials, primarily non-metallic ones.
Working Principle:-Electric current flows through a resistance heating element (usually when conductive materials are to be melted.///Applications:-Used in electric arc furnaces for Principle:-Works on dielectric heating.//Microwaves cause polar molecules (like water) in the
nichrome), which heats the surrounding water.A thermostat controls the water temperature to steel melting and metal refining. material to rotate rapidly, generating internal friction and heat.
avoid overheating. 2.Indirect Arc Heating➔ Applications:-Food processing: cooking, baking, thawing, sterilizing.//Rubber and plastic
Heating Appliances➔1.Electric Irons-Use resistance heating elements to heat a flat metal Principle:-The arc is formed between two electrodes, and the charge is heated indirectly by industries: preheating and vulcanizing.//Chemical and pharmaceutical industries: drying and
base.//Equipped with a thermostat for temperature regulation.//2.Electric Kettles-Boil water radiation from the arc.//Heat Transfer:-Heat is transferred via radiation and convection, not by synthesis.
rapidly using a concealed heating element.//Automatic shut-off using a bimetallic direct contact.///Features:-Suitable for non-conductive or heat-sensitive materials.//Lower Simple Design Problems of Resistance Heating Elements➔
thermostat.//3.Room Heaters-Use wire coils or ceramic plates to generate heat and blow hot efficiency compared to direct arc heating.///Applications:-Used in heating ceramics, refractory Factors in Design:-Required Power Output (W)//Voltage Supply (V)//Material Resistivity (ρ)//
air.//Fan-forced and oil-filled types are common.//4.Toasters & Ovens-Convert electric energy materials, and slag processing. Operating Temperature//Element Dimensions: length (L) and cross-sectional area (A)
into heat via coils.//Use radiant heat to cook or toast food.
Electric Welding➔Electric welding is a process of joining two metal pieces by applying heat Welding Equipment Used➔Common Components: Power Supply Required for Arc Welding➔Types of Power Supply:-
produced from an electric arc or resistance, often combined with pressure and/or filler material (i)Welding Transformer-Steps down voltage and supplies high current.//(ii)Electrodes-Copper Direct Current (DC) Supply:-Polarity:DCSP (Straight Polarity): Electrode negative, work
to form a strong joint.///Advantages :-Strong and Permanent Joints-Produces joints with high alloy electrodes (in spot, seam, projection welding)//Flat or contoured dies (in butt welding)// positive → deeper penetration.//DCRP (Reverse Polarity): Electrode positive, work negative →
mechanical strength.//High Speed and Efficiency-Faster than traditional methods like riveting (iii)Control Unit-Controls time, pressure, and current.//(iv)Pressure Mechanism-Pneumatic or better cleaning action.///Advantages:-Stable arc//Better control on thin metals//Suitable for all
or bolting.//Portable and Flexible-Can be done on-site with portable equipment.//Economical- hydraulic systems apply pressure on the workpieces.//(v)Cooling System-Circulates water to positions
Requires fewer materials and less labor compared to mechanical joining.//Cleaner Process-No cool electrodes and equipment. Alternating Current (AC) Supply:-Frequency: Usually 50 Hz or 60 Hz///Advantages:-
need for holes or extra fittings, and minimal material wastage. Principle of Arc Production➔Electric arc is formed when a high current flows across a gap Cheaper equipment//Simpler design//Suitable for thicker materials
Electric Welding Methods➔ between two electrodes (or electrode and workpiece) through the ionized air (plasma). Power Source Requirements:-Output Voltage: 20 – 100 V (depending on arc type)
Electric welding is mainly divided into two categories: Requires:-A power source (AC or DC)//Electrodes to establish and maintain the arc.// Current Range: 30 – 600 A (based on electrode size and material)
1.Arc Welding➔Arc welding is a fusion welding process that uses an electric arc to melt and Heat generated by the arc can reach 3500–4000°C, enough to melt most metals. Equipment Used:-Welding transformer (for AC)//Welding generator or rectifier (for DC)//
join metals at the welding point.///Principle: Heat is generated by an electric arc between an Electric Arc Welding➔A welding process that uses an electric arc to melt the base metal and Inverter welding machines (compact, efficient, both AC/DC)
electrode and the workpiece.///Types:-(i)Shielded Metal Arc Welding (SMAW): Manual filler material, forming a strong joint upon cooling. Advantages of Using Coated Electrodes➔Coated electrodes (used in SMAW / stick welding)
method using coated electrodes.//(ii)Gas Metal Arc Welding (GMAW / MIG): Uses a Characteristics:-High temperature for melting metals.//Bright visible light (UV & IR radiation are metal rods with a flux coating that improves welding performance.
continuous wire and shielding gas.//(iii)Gas Tungsten Arc Welding (GTAW / TIG): Uses a non- hazard).//Stable arc ensures smooth weld bead.//Sound (buzzing) due to ionization and arc (i)Arc Stability-Flux stabilizes the arc, making it easier to strike and maintain.//(ii)Shielding
consumable tungsten electrode.//(iv)Submerged Arc Welding (SAW): Uses granular flux to noise.//Easily controllable current and arc length. Gas Formation-When flux burns, it produces gas (like CO₂) that protects the molten metal
protect the arc. Types➔ from oxidation and contamination.//(iii)Slag Formation-Flux forms a slag layer on the weld
2.Resistance Welding➔Resistance welding is a process that joins metals by applying pressure 1.Carbon Arc Welding (CAW)➔ Carbon Arc Welding is a welding process in which an bead, protecting it as it cools and improving the weld quality.//(iv)Alloying Elements-Coating
and passing electric current through the metal pieces to generate heat due to electrical electric arc is struck between a non-consumable carbon (graphite) electrode and the workpiece can add alloying elements to improve weld metal properties (like strength or corrosion
resistance.///Principle: Heat is generated by the resistance to electric current at the contact to produce heat for welding.///Working Principle:-A carbon electrode, connected to the power resistance).//(v)Deoxidation-Coating contains substances that remove impurities from the weld
surface of the workpieces.///Types:- (i)Spot Welding: Used for joining thin metal sheets at small source, is held close to the metal workpiece.When the electrode touches and then is slightly pool.
spots.//(ii)Seam Welding: Similar to spot welding, but in a continuous line.// withdrawn, an electric arc forms.The arc produces intense heat (about 3500°C) that melts the Comparison Between AC and DC Arc Welding➔
(iii)Projection Welding: Uses small projections to localize heating.(iv)Flash Butt Welding: metal surface.Filler metal may or may not be added manually to the molten pool. Feature AC Welding DC Welding
Involves flashing and pressing the ends together. Advantages:-Simpler and cheaper than metal arc welding.//Good for welding non-ferrous Power Source Transformer Generator, rectifier, or inverter
Spot Welding➔ Spot welding is a type of resistance welding where two or more overlapping metals like aluminum and copper.///Disadvantages:-Carbon electrode may burn away quickly./ Arc Stability Less stable, especially for thin metals More stable and smooth
metal sheets are joined by applying pressure and passing electric current through small localized Produces a lot of smoke and carbon deposits.///Applications:-Welding of aluminum and Cost Cheaper setup Costlier due to complex equipment
spots.///Principle: Heat is generated at small contact spots by passing a high current for a short copper.//Repair work and brazing.
Polarity Control Not available Available (DCSP or DCRP)
time.//Electrodes: Two copper alloy electrodes press the metal sheets together. 2.Metal Arc Welding (MAW) / Shielded Metal Arc Welding (SMAW)➔ Metal Arc Welding
Applications:-Automobile body manufacturing//Sheet metal fabrication//Home appliances (also called Shielded Metal Arc Welding or SMAW) is a welding process where an electric arc Electrode Limited to AC-rated electrodes Can use both AC and DC electrodes
(refrigerators, washing machines) is struck between a consumable metal electrode and the workpiece to melt and join metals. Maintenance Lower Higher
Projection Welding➔Projection welding is a resistance welding process where the current and Working Principle:-A coated consumable electrode is used as both the filler and arc conductor. Applications Thick metals, general fabrication Precise work, non-ferrous metals, thin sheets
pressure are concentrated on small raised sections (projections) on one or both of the When the electrode touches the metal and is withdrawn slightly, an electric arc forms.The Welding Control Circuits➔Welding control circuits regulate current, voltage, time, and
workpieces. This focuses the heat generation and weld formation at those points./// intense heat (~3500°C) melts the electrode tip and the base metal, forming a molten weld pool. pressure during the welding process to improve quality and consistency.
Principle: Uses small projections (raised sections) on the workpiece to localize heat The electrode coating vaporizes, producing a protective gas shield to prevent oxidation.The Common Components:-Timer: Controls welding duration (esp. in spot welding)//Current
generation.///Features:-Multiple spots can be welded at once.//Requires lower current than spot molten metal solidifies to form a strong weld.///Advantages:-Simple and inexpensive process.// Controller: Adjusts output current as needed//Contactor or Relay: Switches power on/off
welding.///Applications:-Nut and bolt welding//Automotive parts//Electrical components Portable and versatile.//Good for outdoor and fieldwork.//Strong and reliable welds. safely//SCR/Thyristor Control: Inverter-based control for smooth current regulation//
Seam Welding➔Seam welding is a type of resistance welding that produces a continuous or Applications:-Structural steel fabrication.//Shipbuilding and pipeline welding.//Repair and Feedback System: Maintains consistent welding output//These control circuits are crucial in
intermittent weld along a joint by using rotating wheel electrodes that roll over the overlapping maintenance work. automated welding systems.
metal sheets.///Principle: Similar to spot welding, but uses rotating wheel-shaped electrodes to 3.Hydrogen Arc Welding➔Hydrogen Arc Welding is a welding process where an electric arc Welding of Aluminum and Copper➔Challenges:-High thermal conductivity → rapid heat
make a continuous weld seam. is maintained between two tungsten electrodes in an atmosphere of hydrogen gas, which acts loss//Oxide layers on surface → requires cleaning//Aluminum: Forms refractory oxide (Al₂O₃)
Types:- (i)Intermittent seam//(ii)Continuous seam as a shielding and reducing environment.///Working Principle:-An arc is struck between two //Copper: Requires high heat input
Applications:-Fuel tanks//Oil drums//Leak-proof containers non-consumable tungsten electrodes.The welding is done in a hydrogen atmosphere to prevent Suitable Methods:-
Butt Welding➔Butt welding is a resistance welding process where two metal pieces are joined oxidation and contamination.Hydrogen gas dissociates under heat, releasing atomic hydrogen Metal Welding Method Notes
end-to-end (butt joint) by applying pressure and passing electric current to heat and fuse the which recombines on the metal surface, releasing heat and cleaning the weld area.The heat Aluminum TIG (GTAW), MIG AC TIG for oxide cleaning, inert gas shielding
surfaces.///Principle: Ends of two components are heated by resistance and then pressed generated by the arc and recombination of hydrogen melts the base metal to form the weld.
Copper TIG, Oxy-acetylene, MIG High current needed, pre-heating often used
together. Advantages:-Produces high-quality, clean welds.//Reducing atmosphere prevents oxidation
Types:- (i)Flash butt welding//(ii)Upset butt welding and contamination.///Applications:-Welding of stainless steel, titanium, and other corrosion-
Applications:-Railway tracks//Rods and wire joints//Pipe and tube joining resistant alloys.//Joining thin sheets and precision components.

TIG Welding (Tungsten Inert Gas Welding)➔Also known as: GTAW – Gas Tungsten Arc Process of Electro-deposition➔Electro-deposition is the process of coating a metal object Galvanizing➔Principle:-Galvanizing is the process of coating iron or steel with a layer of
Welding///Features:-Uses a non-consumable tungsten electrode//Separate filler rod is added with another metal using an electric current in an electrolyte solution. The goal is often to zinc to prevent rusting.Zinc acts as a sacrificial anode, protecting the base metal even if the
manually (optional)//Shielding gas (argon or helium) protects the weld area from improve appearance, corrosion resistance, or mechanical properties. coating is scratched.This protection works by electrochemical means, known as cathodic
contamination.//Produces clean, precise, high-quality welds.///Advantages:-Ideal for thin 1.Cleaning (Surface Preparation):-Proper cleaning is essential to ensure good adhesion of the protection./// Process (Hot Dip Galvanizing):-Clean the iron surface//Dip into molten zinc
metals//Suitable for non-ferrous metals (aluminum, copper, titanium)//No spatter and minimal deposited metal.//Degreasing: Removes oil and grease using solvents or alkaline cleaners.// (~450°C)//Cool and solidify the coating///Applications:-Steel structures (bridges, poles)//
cleanup//Superior control over the welding process./// Limitations:-Slower process//Requires Acid Pickling: Removes rust or oxide layers using dilute acid (e.g., HCl).//Water Rinsing: To Roofing sheets and pipes//Fencing wires//Automotive parts//Hardware tools
skilled operator//Not ideal for thick or large welds.///Applications:-Aerospace and aircraft wash off any chemical residues after each step./// 2.Operation / Electroplating Setup:- Anodising➔Principle:-Anodising is an electrochemical process to form a thick oxide layer on
parts//Stainless steel and aluminum structures//High-precision industries Workpiece (cathode): The object to be plated (negative terminal).//Anode: Usually a rod or plate the surface of metals like aluminum.The metal becomes the anode in an electrolytic cell.Oxygen
MIG Welding (Metal Inert Gas Welding)➔Also known as: GMAW – Gas Metal Arc Welding of the metal to be deposited (positive terminal).//Electrolyte: A solution containing metal ions released at the anode reacts with the metal to form a protective and decorative oxide film.///
Features:-Uses a consumable wire electrode that melts and joins the metal//Wire is (e.g., CuSO₄ for copper).//Power Supply: Provides DC current to drive the electrochemical Process:-Use dilute sulfuric acid as the electrolyte//Apply DC current with aluminum as
automatically fed through a spool//Shielding gas (CO₂, argon, or mix) protects the weld pool// reaction.///3.Deposition of Metals:-When current flows, metal ions from the electrolyte are anode//The oxide layer thickens and can be dyed for color.///Applications:-Aluminum window
Suitable for high-speed, continuous welding.///Advantages:-Easy to learn and use//Faster reduced at the cathode and get deposited as a metallic layer.At the same time, anode metal frames, cookware//Aircraft and automotive parts//Corrosion and wear protection
welding speed – ideal for production//Suitable for thicker materials.///Limitations:-More dissolves to replenish metal ions in the solution. Factors influencing deposition:-Current Manufacture of Chemicals by Electrolytic Process➔
spatter than TIG//Not as clean or precise as TIG//Sensitive to wind (not ideal for outdoor use) density//Time//Solution temperature//Metal concentration and pH.///4.Polishing:-Done after Electrolysis is widely used in the chemical industry to produce important compounds.
Applications:-Automotive industry//Structural steelwork//Industrial fabrication and repair plating to smoothen the surface using abrasives or fine polishing wheels.//Removes surface Examples:-
Electrolytic Processes➔Electrolytic processes involve the chemical decomposition of an irregularities, scratches, or dullness.//Ensures an even, attractive finish.///5.Buffing:-Final Chemical Electrolyte Product Formed
electrolyte by the passage of electric current. It is a key process in industries like metal refining, glossy finish is achieved using a buffing wheel and polishing compounds.//Enhances shine and Caustic soda (NaOH) Brine (NaCl solution) NaOH, Cl₂, H₂
electroplating, and battery manufacturing. reflectivity of the plated surface.//Often used for decorative finishes like chrome or silver
Chlorine gas (Cl₂) Brine Chlorine
Need for Electro-deposition:-Electro-deposition is the process of depositing a metal coating plating.
on an object using an electric current. Equipment and Accessories for Electroplating➔ Hydrogen gas (H₂) Water or brine Hydrogen
Why Electro-deposition is Needed➔Corrosion Protection-Coating metal (e.g., zinc on iron) 1.Electrolytic Tank:-Made of plastic, rubber-lined steel, or glass to resist corrosion.//Holds the Aluminum (Al) Molten bauxite (Al₂O₃) in cryolite Pure aluminum
to prevent rust.//Improved Appearance-Decorative finishes using gold, silver, chrome, etc.// electrolyte solution in which electro-deposition takes place.///2.Power Supply (DC Source):- Sodium metal (Na) Molten NaCl Sodium
Repair of Worn Parts-Depositing material to rebuild worn mechanical parts.//Electrical Supplies direct current (DC), typically 6–12 volts.//Constant voltage or current-controlled Copper refining CuSO₄ Pure copper
Conductivity-Depositing conductive metals (like copper) for electronics.//Hardness and sources are used depending on the process.///3.Electrodes:-Cathode (workpiece): The item to
Wear Resistance-Adding hard metals to improve surface durability.//Cost Saving-Using a be plated (negative terminal).//Anode: Either soluble (metal to be deposited) or inert (platinum, Electrolysis Process➔Principle:-Electrolysis is the chemical decomposition of a compound
cheaper base metal and coating it with an expensive metal layer (like gold or silver). graphite).///4.Electrolyte (Plating Bath):-A solution containing metal salts (e.g., CuSO₄ for (electrolyte) by passing an electric current through it.
Laws of Electrolysis➔Stated by Michael Faraday, the laws govern the relationship between copper plating).//May also include additives for leveling, brightness, and pH control.///5.Anode Key Points:-Anode: Positive electrode (oxidation occurs)//Cathode: Negative electrode
electric current and amount of substance deposited. and Cathode Holders:-Fixtures to hold and suspend the anode and cathode in the (reduction occurs)//Ions in solution move to oppositely charged electrodes
Faraday's First Law:-"The mass (m) of a substance deposited or liberated at an electrode is electrolyte.//Ensure good electrical contact and uniform positioning.///6.Agitation System:- Applications:-Metal extraction (Al, Na, Mg)//Electroplating//Purification of metals//
directly proportional to the quantity of electricity (Q) passed through the electrolyte." Helps maintain uniform ion concentration around electrodes.//Can be mechanical stirrers or air Manufacture of chemicals (e.g., NaOH, Cl₂, H₂)
Formula:-m=Z⋅Q=Z⋅I⋅t.////Where:-m = mass of substance deposited (grams)//Z = bubbling systems.///7.Heating and Cooling System:-Used to control electrolyte temperature,
electrochemical equivalent (ECE)//I = current (amperes)//t = time (seconds) which affects deposition rate and quality.//Heating coils, thermostats, or chillers may be
Faraday's Second Law:-"When the same quantity of electricity is passed through different included.
electrolytes, the mass of substances deposited is proportional to their chemical equivalent Factors Affecting Electro-deposition➔
weights."///Formula:-m1/E1=m2/E2 1.Current Density:-Higher current → faster deposition but may cause rough surfaces.//Must
Where:-m = mass of substance deposited//E = equivalent weight = (Atomic mass / Valency) be optimized for uniform coating and adhesion.///2.Electrolyte Composition:-The type and
Electroplating on Non-conducting Materials➔Principle:-Non-conductive materials (like concentration of metal salts and additives influence deposition quality.///3.Temperature of
plastics, ceramics) cannot be electroplated directly.They must first be made conductive by Electrolyte:-Higher temperature generally increases ion mobility, improving plating speed.//
applying a thin conductive layer.///Steps:-Cleaning and etching the surface//Sensitizing with Excessive temperature may cause burnt or uneven deposits.///4.pH of Solution:-pH affects the
stannous chloride (SnCl₂)//Activating with palladium chloride (PdCl₂)//Electroless plating of stability and conductivity of the solution.//Needs to be maintained within a specific range for
a thin metal layer//Followed by normal electroplating each metal.///5.Time of Plating:-Longer time results in thicker coating.//Over-plating may lead
Applications:-Decorative chrome plating on plastic car parts//Printed Circuit Boards (PCBs)// to brittle or flaky deposits.///6.Agitation:-Stirring or moving the solution/workpiece improves
Fashion accessories//Lightweight metallic finishes ion availability at the electrode surface.//Prevents localized concentration drops and ensures
even plating.///7.Electrode Distance:-The spacing between anode and cathode affects
resistance and plating uniformity.//Too close → high current, overheating; too far → slow
deposition.///8.Surface Preparation:-Dirty or oxidized surfaces result in poor adhesion or
flaking of metal.//Proper cleaning is crucial before plating.