Types of Electrical Machines

 

Machine Type	Description	Common Applications
Direct Current (DC) Machines	These machines operate on DC power sources and include:
- DC Motor	Converts electrical energy into mechanical energy, generating rotary motion	Used in electric vehicles, industrial equipment, and appliances
- DC Generator	Converts mechanical energy into electrical energy, producing a DC voltage	Common in older power generation systems and battery charging
Alternating Current (AC) Machines	These machines operate on AC power sources and include:
- Induction Motor	Utilizes electromagnetic induction to rotate a shaft without brushes	Widely used in industrial applications and household appliances
- Synchronous Motor	Runs at a constant speed synchronized with the supply frequency	Common in applications requiring precise control of speed
- Transformer	Transfers electrical energy between two or more windings through electromagnetic induction	Essential for voltage transformation and power distribution
- Alternator (AC Generator)	Converts mechanical energy into AC electrical energy	Used in power generation, including in power plants and engines
- 1-Phase Induction Motor	A single-phase AC motor used in various small appliances and fans	Common in household fans, pumps, and small machinery
- Shaded Pole Motor	A type of single-phase AC motor known for its simplicity and reliability	Used in applications like refrigeration, fans, and small appliances
- Repulsion Motor	Operates using brushes and a commutator, providing high starting torque	Used in high-torque applications, such as elevators and machine tools
- Universal Motor	Operates on both AC and DC power sources, suitable for high-speed applications	Found in small kitchen appliances, power tools, and vacuum cleaners
- Hysteresis Motor	Utilizes the hysteresis effect in magnetic materials for smooth, synchronous rotation	Used in applications like turntables, clocks, and timing devices
Specialized Machines	Machines designed for specific tasks and applications:
- Brushless DC Motor	A DC motor without brushes for improved efficiency and reduced maintenance	Washing machines, compressors, robots, CNC Machine tools
- Stepper Motor	Converts electrical pulses into precise incremental movements	Common in CNC machines, 3D printers, In biomedical applications such as X-ray machines, CT scan,and robotics
- Linear Induction Motor	Creates linear motion without mechanical contact	Applied in high-speed transportation systems and conveyor belts
- Servo Motor	A high-precision motor designed for closed-loop control systems	Computers, Robotics and toys, CD/DVD players, Textile industries Tracking and guidance system Self-balancing recorders, Remote positioning devices, Process controllers, Electromechanical actuators Air-craft control system, Programming device
- Synchronous Reluctance Motor	Utilizes the reluctance effect in magnetic materials for energy-efficient operation	Found in industrial applications, electric vehicles, and wind turbines
- Permanent Magnet Synchronous Motor	Employs permanent magnets in the rotor for efficient, synchronous operation	Used in applications like HVAC systems, robotics, and industrial machinery

Parts of Transformer

 

Part	Function	Material Used
Core	Provides a path for magnetic flux, increasing or decreasing voltage through electromagnetic induction	Laminated iron or steel core
Windings (Primary & Secondary)	Primary winding receives the input voltage, while the secondary winding provides the output voltage	Copper or aluminum wire with insulation
Insulation	Electrically insulates and isolates the windings from the core and each other	Paper, pressboard, varnishes, or plastics
Transformer Tank	Encloses the core and windings, protecting them from environmental factors and providing structural support	Steel, stainless steel, or other suitable materials
Cooling System	Removes excess heat generated during operation to maintain safe operating temperatures	Mineral oil, synthetic oil, or other dielectric fluids
Bushings	Provide electrical insulation and support for the conductors where they enter or exit the transformer tank	Porcelain, polymer, or other insulating materials
Tap Changer	Allows for voltage adjustments by altering the number of turns in the winding	Copper, typically silver-plated, with insulating materials
Gaskets and Seals	Prevent leaks and ensure the transformer tank remains sealed and oil-tight	Rubber, cork, or other sealing materials
Breather	Regulates the air pressure inside the transformer tank as the oil expands or contracts	Silica gel or other desiccant materials
Conservator	Stores excess oil and compensates for oil level changes during temperature variations	Steel or other suitable material for the tank, plus rubber or plastic components for expansion
Nameplate	Provides essential information about the transformer, including its specifications and ratings	Typically made of metal or plastic

Parts of Three Phase Induction Motor

 

Part	Function	Material Used
Stator	Generates a rotating magnetic field when supplied with 3-phase AC power	Laminated electrical steel sheets, copper or aluminum windings
Rotor	Responds to the magnetic field, generating torque and causing rotation	Aluminum or copper bars and end rings
Bearings	Support the rotor and reduce friction for smooth rotation	Steel, with components like steel balls or rollers
Frame	Provides structural support for the motor and dissipates heat	Cast iron or aluminum
End Covers	Enclose the motor, protecting internal components	Cast iron, aluminum, or plastic
Cooling Fan	Dissipates heat during operation, maintaining a safe temperature	Plastic or metal
Terminal Box	Houses electrical connections for stator windings	Plastic or metal, with insulation
Shaft	Connects the rotor to external equipment, transmitting mechanical power	Steel, stainless steel, or suitable material
Enclosure	Protects internal components from environmental factors	Cast iron, aluminum, plastic, or other materials
Stator Winding	Consists of insulated copper or aluminum wire coils that generate the magnetic field in the stator	Copper or aluminum wire with insulation
Rotor Winding	Made up of insulated copper or aluminum bars and end rings, responding to the magnetic field in the stator	Copper or aluminum bars with insulation
Eye Bolt	Provides a lifting point for handling and installation of the motor	Steel or other suitable materials for strength and durability
Slip Rings	Electrical components used in slip ring rotors to transfer electrical power and control signals to the rotor	Typically made of brass, copper, or other conductive materials
Carbon Brushes	Brushes that maintain contact with the slip rings, allowing for the transfer of electrical current	Made of carbon or other suitable materials with good conductivity

DC Motor Parts

Component	Function	Typical Materials Used
Stator	Generates a magnetic field	Laminated iron or steel
Rotor	Rotating part of the motor; includes armature and commutator	Armature: Iron or laminated steel Commutator: Copper or copper segments
Armature Windings	Carries current, interacts with the magnetic field, and generates mechanical motion	Copper or aluminum wire
Brushes	Supply electrical current to the armature	Carbon or graphite
Bearing	Supports the rotor shaft and reduces friction	Steel or ceramic
Housing or Frame	Provides structural support and protection for the motor	Aluminum, steel, or plastic
End Caps	Protect internal components and secure bearings	Metal or plastic
Shaft	Transmits mechanical output to external devices or machinery	Steel
Cooling Fan	Provides cooling airflow to maintain an optimal operating temperature	Plastic or metal
Eye Bolt	Provides a point for lifting, suspending, or securely fastening the motor	Steel or other durable materials
Field Pole	Part of the stator that concentrates the magnetic field	Laminated iron or steel
Field Winding	Coils of wire that produce the field magnetic field	Copper or aluminum wire
Yoke	Supports and completes the magnetic circuit in the motor	Iron or steel

Fig Ref: electricaleasy

Behavior of Single Phase Induction Motor

 Single-phase induction motors are not inherently self-starting for several reasons:

Lack of Rotating Magnetic Field: In a three-phase induction motor, a rotating magnetic field is easily created by the three-phase AC power supply, which initiates the rotation of the rotor. However, in a single-phase motor, only a pulsating magnetic field is generated, which does not create the necessary torque to start the motor.

Unbalanced Torque: The pulsating magnetic field in a single-phase motor produces an unbalanced torque on the rotor, causing it to stall or not start at all. This is because the torque produced during one half of the AC cycle opposes the torque during the other half.

Starting Methods: To overcome the lack of self-starting ability, single-phase induction motors often employ auxiliary mechanisms, such as start windings, capacitors, or shaded poles. These methods create a phase shift or additional magnetic fields to help the motor start.

External Assistance: Single-phase motors may require manual assistance like giving the rotor a push to initiate rotation during startup. Once the motor starts rotating, it can continue to run on its own due to the interaction of the rotor and the alternating magnetic field.

In summary, single-phase induction motors lack the balanced rotating magnetic field necessary for self-starting, and they typically require additional components or mechanisms to overcome this limitation and initiate rotation.

Single Phase Induction Motor

The "Double-Field Revolving Theory" is a concept used to explain the operation of single-phase induction motors. This theory helps in understanding how these motors can produce a revolving magnetic field and the resulting rotation of the rotor. Here's a simplified explanation of the theory: Single-Phase Supply: Single-phase induction motors are connected to a single-phase AC power supply, which produces a pulsating magnetic field. Split-Phase Windings: In a single-phase motor, two windings are used – the main winding (or running winding) and the auxiliary winding (or starting winding), which are physically displaced by an angle of 90 degrees from each other. Revolving Magnetic Field: When AC voltage is applied to these windings, it produces two magnetic fields that are 90 degrees out of phase. This results in a magnetic field that appears to rotate in space, despite the fact that the supply voltage is not three-phase. Starting Torque: The rotating magnetic field induces currents in the rotor, creating a starting torque. The auxiliary winding, often connected in series with a capacitor, provides the phase shift needed to create this torque. Rotor Movement: As the rotor is subjected to the rotating magnetic field, it starts to follow the field's rotation and begins to turn. Once the rotor reaches a sufficient speed, the starting winding may be disconnected or de-energized, and the motor continues to run using the main winding alone. In summary, the Double-Field Revolving Theory explains how a single-phase induction motor effectively generates a revolving magnetic field by using two windings with a phase difference. This revolving magnetic field initiates the rotation of the rotor, allowing the motor to start and operate on a single-phase power supply.

Indian EV eco system

 

India's EV Policy The NITI Aayog, India's policy think-tank, has given several suggestions to the Government of India with respect to EVs. Accordingly, the following policy has been enacted: Reduce primary oil consumption in transportation. Facilitate customer adoption of electric and clean energy vehicles. Encourage cutting edge technology in India through adoption, adaptation, and research and development. Improve transportation used by the common man for personal and goods transportation. Reduce pollution in cities. Create EV manufacturing capacity that is of global scale and competitiveness. Facilitate employment growth in a sun-rise sector Government adopted the Faster Adoption and Manufacturing of Hybrid and EV (FAME) scheme in 2015, with an allocation of Rs. 895cr, which provided subsidies for e-2Ws, e-3Ws, hybrid and e-cars and buses. The FAME II scheme, which came into effect from April 2019, had a proposed spending of Rs. 10,000cr. It was to be used for upfront incentives on the purchase of EVs (to the extent of Rs. 8,600cr and for supporting deployment of charging infrastructure (Rs. 1,000cr).

Source: Department of Heavy Industries, Ministry of Heavy Industries and Public Enterprises, Government of India

The EV Ecosystem

Source: Avendus Capital Pvt Ltd

Policy: The FAME II policy is India's first step towards boosting EV penetration in India, though a lot needs to be done. The Government has taken baby steps by introducing e-buses for public transport in some cities. EVs for private use will go up once there are incentives, subsidies and other such measures. Batteries: Battery cost is nearly 40% of the cost of the vehicle, hence reducing the same is key to increasing EV adoption. Raw materials for battery manufacturing - mainly Lithium and Cobalt - are not available in India, hence raw material dependency will continue (currently India imports crude). Currently Indian companies only assemble imported battery packs, do not manufacture batteries.

Source: Times of India

OEM: Most OEMs are focused on specific sub-segment of the automobile space. 2Ws have seen the most momentum, given that nearly 79% of Indian auto market (by volumes) comprises of 2Ws. E-3Ws have started by way of e-Rickshaws while e-4Ws are gaining prominence in shared mobility.

Source: Trade Brains

Grid: There are two major issues that grids have to address Ability to handle peak load Grid composition must be ideally dependent on renewable generation rather than coal dependent generation. Charging Infrastructure: India will need to simultaneously develop home charging and public charging infrastructure to boost EV adoption. The government has been pushing for EVs through introduction of Fame I & II policy with a major focus on charging infrastructure. The government, under FAME II policy approved setting up of 1633 fast charging stations and 1003 slow charging stations across 62 cities, 24 states and union territories in Jnuary 2020. FAME I added 314 charging stations in India, FAME II 2,867

Source: FADA

Customers: EV adoption in India is highest in the public transport (buses) and shared mobility. E-2Ws have been the next ones to begin adopt since cost differential between ICE 2Ws and EV 2Ws is lower than 4Ws. Lithium ion price reduction - the biggest enabler While demand for Lithium is expected to increase with growing EV adoption, prices, surprisingly have continued to fall continuously. Over the past ten years (2010 - 2020), Lithium prices have dropped 88%. This is due to the following reasons: Annual supply of Lithium is expected to grow from 2,15,000 tonnes in 2019 to 7,15,000 tonnes in 2025. This will be led by new supply from Argentina, Australia and Chile. Three new mines are set to come up in North America in next couple of years, taking its share in global supply to 5% by 2025. New mines and increased production have brought a glut of material to market, hammering lithium prices.

Volume Weighted average of lithium ion battery price (USD) Lithium production to triple between 2019 and 2025 Lithium Reserves by country (In Million Metric Tons)

While lower Lithium prices is music to ears of Auto OEMs, it is bad news for miners of the metal. Lower prices means that investments into mining may become less profitable, reducing the pace of new investments. The pandemic reduced demand for EVs, hereby depressing prices further. However, the free fall in Lithium prices is expected to get arrested by 2022. Several global companies have delayed or postponed expansion plans due to depressed demand currently. Some examples of postponed projects are: Chile's SQM, the world's second-largest Lithium producer, postponed key expansion at its Atacama salt flat operations from the end of 2020 to late 2021. Australian company Wesfarmers delayed its investment decision on the Mount Holland project in Western Australia by a year, to early 2021. World leader Albemarle postponed its project to buy 1,25,000 tonnes of processing capacity. It also revised a deal to buy into Australia's Mineral Resources' (ASX: MIN) Wodgina lithium mine and said it would delay building 75,000 tonnes of processing capacity at Kemerton, also in Australia. (Source: Mining.com) China's Tianqi Lithium Corp., the country's top producer of the battery metal, also postponed commissioning the first phase of its flagship plant in Kwinana, as it struggles to pay back debt. (Source: Mining.com) Reference: Research and Ranking -Prashant Gorakhnath Patil

ELECTRIC VEHICLE

  Most of us, like many other inventions, had not heard about cars powered by electricity before. If one would tell us about electric vehicles becoming the future of mobility probably a decade ago, we perhaps would not believe it. However, it's turned into a reality now. E-vehicles are sitting in the driver's seat and driving the Automobile sector towards growth.

Vehicle electrification: a brief history

Electric Vehicles or EVs, as they are commonly called, are vehicles which run on electric power, either partly or fully. EVs are environment-friendly and have low running costs due to lesser moving parts.

Surprisingly, the concept of EVs is older than Internal Combustion Engines (ICEs). Scottish inventor Robert Anderson created the first electric carriage in the 1830s. Its battery wasn't rechargeable and required replacement every time it ran out. However, electric-powered continued to be in use in USA and some parts of Europe. New York had a fleet of electric taxis in the 19th century and battery swapping stations.

With the advent of ICEs, a major roadblock of frequent battery charging / swapping was removed and ICEs gained popularity world over. Thereafter, there was sporadic research on EVs whenever crude oil flared or geo-political tensions mounted. However, for a large part, ICEs rules the roost.

It was not until the turn of the century that EV development found serious interest from companies and Governments. Companies such as Toyota (Prius), Nissan (LEAF) and Tesla (Model S) took the EV chapter ahead and "glamorized" EVs. Here's a look at the EV evolution:

The EV Journey

    Source: Research Gate

India's Affair With EVs is Older Than You May Think

Source: Electricvehicle.com

Source: Wikipedia.org

Most of you would have first heard of Electric vehicles when Reva was launched in 2001. REVA which stands for "Revolutionary Electric Vehicle Alternative", was launched by a Bengaluru based automaker RECC (Reva Electric Car Company) founded by Chetan Maini. It was a joint venture between (JV) between the Maini Group of Bengaluru and Amerigon Electric Vehicle Technologies (AEVT Inc,) of the US. In 2010, RECC was acquired by Mahindra & Mahindra.

However,the first EV to launch in India was Lovebird in 1993. Loverbird was manufactured by the Eddy Electric. The vehicle was first uncovered at the Delhi Auto Expo. The vehicle managed to impress the Indian government at the launch and soon received a green signal from the authorities.

But a two-seater Loverbird, didn't receive as much love as expected from the Indian car buyers. Due to a slew of problems like, the battery used in the car at that time would take 8 hours to charge and the power failures and deficiency on the part of proper electric supply, sales volume didn't ever cross a three-digit figure. Following the low sales number, the government soon withdrew subsidy for buying EVs. This made EVs heavy on Indian consumers' pockets.

Fast Forward A Few Years Later
India is charged to achieve the status of a global hotspot for electric mobility. The Indian automobile industry currently ranks 5th in the world and is set to become the 3rd largest by 2030. The requirement of mobility is going to change drastically in the near future catering to over 1.3 billion population. The past modes of transport and infrastructure will not be able to serve the needs.

Considering this aspect, the government is working towards developing a mobility option which Shared, Connected and Electric as one report by Innovation Norway quotes.

Under the Make In India programme, the manufacturing of e-vehicles and auto parts is expected to increase the share of manufacturing in GDP to 25% by 2022. Currintly 82% of India's oil demand is sufficed by imports from oil rich country. Adoption of EVs, as per several estimates, is projec

Moreover, the price of electricity as fuel could fall as low as Rs. 1.1/Km, helping an electric vehicle owner save up to Rs. 20,000 for every 5,000km traversed.

Why EVs - advantages

So why has the world started looking at EVs as the technology of the future? Aren't we happy driving petrol/diesel driven vehicles? Ma be not. Following are some reasons:

1. Climate change - Effects of fossil fuels such as global warming, mass extinction of species and growing weather calamities have forced lawmakers across the global to look at cleaner alternatives.


2. Import bill - Countries such as India don't have any significant crude reserves and have to import the fossil fuel for their energy requirements. India incurred a crude import bill of $101bn in FY20 requiring to import 82% of its total crude needs. Hence, there is growing interest in technologies that look away from crude oil dependency - electric vehicles being one of them.


3. Pollution level - According to WHO, India is home to 14 of the world's 20 most polluted cities. A major reason for high pollution levels is fuel emissions.


4. Advancing renewable energy technology - Over the past few years, strong advancements in wind and solar energy have brought down the cost of these form of energies. This has stirred interest in EVs.


5. Low maintenance - While an IC vehicle has hundreds of moving parts, an EV has less than 30. This means less wear and tear and low cost of ownership.


6. Quieter operation - EVs make much lower noise compared to conventional vehicles since there's lower friction between moving parts. In fact, EVs are so silent that some OEMs add false sounds to make them safe for pedestrians!


7. Incentives for buyers - Governments in India (State and Central) are looking at ways to incentivize buyers to go in for EVs. They are offering lower vehicle tax, tax incentives, buyback.

Reference: Research And Ranking

-Prashant Gorakhnath Patil