PowerPoint Presentation

[Audio] Good morning everyone and welcome. I am very excited to share with you my views about electrical energy utilization and conservation. The topic of this presentation is EE3001- Utilization and Conservation of Electrical Energy Vertical I: Power Engineering. We will be discussing topics such as electric drives, power source, power controllers, control units, motors, sensing units, and loads and their respective functions. So, let's get started!.

[Audio] In this slide, we will explore the fundamentals of electric drives and traction. We will look at the different types of electric motors used for various services, as well as the power transformers, traction generator sets, and traction motors. We will also delve into the characteristic features of traction motors, the various types of systems of railway electrification, electric braking, and how to optimize energy consumption for train movement, as well as traction motor control and track equipment and collection gear..

[Audio] Electric drives are essential components for multiple industrial processes and control systems. They enable precise control of the rotation of the motor shaft, consisting of an electric motor, an energy transfer device and a working machine. Electric drives provide exact motor output and response to controlling inputs, thus facilitating an optimal motion control. As such, they offer effective management and consumption of electrical energy..

[Audio] We will now discuss the block diagram of electric drives and electric motors. Power source is connected to a power converter, and control unit receives an input command as reference. This command dictates the operations of the drive. Motor also has sensing unit to determine speed and torque of movement. Finally, load is driven by the motor or the drive itself. We will cover these components in more detail in the following slides..

[Audio] Understanding the utilization and conservation of electrical energy is an essential part of power engineering. This unit will zero in on two significant components of power engineering, the power source and the power controller or converter. The power source is responsible for providing the essential power for the system to function, whereas the power controller or converter converts the input electrical energy into mechanical energy that can be used for the motor. Furthermore, the controller also helps in controlling the power input to the motor while restraining current during transient operations such as starting or braking. Having detailed knowledge of the utilization and conservation of electrical energy allows us to create more productive systems that help conserve energy and resources..

[Audio] The Control Unit and Sensor Unit are major components of the power converter system, performing the action of controlling the power converter based on the input it is given and the feedback signal it receives from the load. The Control Unit works in tandem with the Sensor Unit to sense the voltage or current signal, providing necessary feedback to ensure the power converter functions under the correct conditions. Additionally, the Sensing Unit is responsible for detecting the current or speed of the motor, as well as protecting and providing closed-loop operation..

[Audio] The electric motor is a critical component of any electrical system. It is mainly responsible for converting the applied energy into mechanical motion. DC motors are used in series, shunt or compound form, and AC motors use slip-ring induction motors. Stepper motors and brushless DC motors are used in special cases. The load, which is a part of the system, is chosen according to the torque and speed characteristics of the system, such as pumps and machines. It's important that the electric motor and load provide compatible torque and speed characteristics for the system as a whole..

[Audio] This slide deals with the classification of electric drives which include DC and AC drives. DC drives use DC motor along with power electronic converters and are mainly used for adjustable speed drives and position control. On the other hand, AC drives can be further classified into induction motor drives and synchronous motor drives and they are lighter than DC drives. Both AC and DC drives are used extensively in various industries, such as manufacturing and transport, to meet the increasing demand for higher efficiency and energy savings. Each drive type has its own advantages and limitations and are utilized based on the application..

[Audio] In the Electrical Drives vertical, one of the key components of a drive is its mode of operation. This slide focuses on the three major modes of operation; Steady State, Acceleration, and Deceleration. In Steady State mode, motor and load torques must be equal in order for the desired speed to be realized. To achieve this, the steady state motor speed torque curve must be appropriately adjusted. Acceleration occurs when load torque is less than motor torque, causing motor torque to exceed the load torque and thus reach the desired speed without exceeding the preset maximum speed. Deceleration involves reducing the speed of the motor, and is achieved when the load torque is greater than the motor torque. This causes the motor torque to drop below the load torque and therefore the motor speed, subsequently reduces. The operation of an electrical drive or motor is contingent on these three modes of operations, so it is important to understand and execute them correctly..

[Audio] Motor operation utilizes acceleration and deceleration modes, which are transient modes, to successfully increase the speed torque. Motor torque must thus exceed the load torque for this to happen. The time taken for a given change in speed is dependent on the motor load system inertia and the difference between the motor and load torque. It is imperative to be aware of the resulting motor current and make sure it does not exceed the rated value, especially if acceleration occurs for an extended period of time..

[Audio] It is essential to not only employ energy resourcefully but also to save it in the present times. When it pertains to motors and power regulates, it is significant that the most current allowed is safe. Furthermore, the drop in source voltage caused by the current should be taken into account and must be within acceptable confines. In specific applications, a motor must initiate without any jerk, enabling it to drive along steadily. To reach this, the starting torque from zero must be able to rise steadily, referred to commonly as soft start..

[Audio] It is essential to understand how to decelerate the motor to secure the needed deceleration. In some cases, only reducing the motor torque to zero works, yet in other circumstances, additional mechanical brakes might be required to reduce the speed of the motor and achieve the desired deceleration. This is important to ensure the effective utilization and preservation of electrical energy..

[Audio] Electric drives are essential to our daily life, with uses ranging from industrial to domestic. Electric drives are the force behind pumps, fans, motors, transport, and solar powered vehicles. They are found in lathe machines, shears, frequency converters, air compressors, refrigeration and air conditioning, and belt conveyors, to name a few. In sum, electric drives are a foundation for a variety of mechanical systems..

[Audio] Electrical drives offer great flexibility in operation and offer a wide range of torque, speed and power variations. They are also suitable for use in hazardous and radioactive environments. They can operate in all four quadrants of speed-torque mode, can be started instantly and can be fully loaded immediately. The control gear needed for speed control is generally simple and easy to use, making them even more beneficial..

[Audio] Selection of an electric motor for an electrical drive requires careful consideration of many factors. Key aspects include the steady-state requirements like the nature of speed torque characteristics, speed regulation, speed range, efficiency, duty cycle, and type of operation. Additionally, transient operation requirements like values of acceleration and deceleration, starting, braking and reversing performance must also be considered. Furthermore, requirements related to the power source like type of source and its capacity, the magnitude of voltage, voltage fluctuations, power factor and harmonics are key points for selection of the appropriate motor. All these must be taken into account to make an informed decision..

[Audio] Consideration of capital and running costs, maintenance needs and life, as well as space and weight restrictions depending on the application, is essential for efficient utilization and conservation of electrical energy. Moreover, the environment and location should be taken into account when selecting the appropriate equipment. Ultimately, the system reliability must be evaluated..

[Audio] Electric power is used to pull vehicles over a surface, commonly railways or roads. This power can come from overhead wires, third rails, storage batteries or diesel generators on the vehicles themselves. Electric traction is a popular choice in trains, tramcars, trolley buses and hybrid vehicles due to its efficiency and cost-effectiveness for long distances. As electric traction systems become more advanced, they will remain a major part of the transportation world..

[Audio] We will be discussing the advantages of electric traction. It is free from smoke and flue gases, making it suitable for underground and tubular railways. Electric locomotives can be started quickly with no loss of time. Maintenance costs for electric traction are half of steam traction and require less time. Electric motors have a very high starting torque, providing a highly accelerated start. Traffic handling capacity of electric locomotives is almost double that of steam locomotives. The high traffic handling capacity and fast start times also require less terminal space. Electric traction makes use of regenerative braking, which is more efficient than mechanical brakes, as it feeds back 80% of electrical energy to the supply..

[Audio] I am going to discuss the advantages of using electric locomotives. Electric locomotion has multiple benefits such as a lower center of gravity due to its low height making them more suitable to take curvy turns at higher speeds. Utilizing electric locomotives is also beneficial as it cuts down the need for high grade coal, that is scarce in India, as electricity for the locomotives is usually generated from low grade coal used in thermal power stations or hydro-electric power stations. Also, electric traction has a higher coefficient of adhesion compared to unbalanced forces produced by reciprocating masses, which reduces the weight to power ratio of locomotives. Moreover, electric traction has a high power-to-weight ratio and encourages rural electrification. To summarize, electric locomotives have multiple advantages..

[Audio] Electric traction is a valuable and efficient form of transport, however it comes with some disadvantages. Firstly, due to the overhead infrastructure required, it has a high capital cost, so it is not financially viable unless there is a large demand. Secondly, a power failure may cause a short disruption to the service. Thirdly, it is only possible to use electric traction in locations that have been electrified. In addition, electric traction is dependent on electric routes and power lines can interfere with communication lines that are close by. Lastly, in order to prevent corrosion of underground pipes, a negative booster needs to be installed in the electric traction system..

[Audio] Power transformers are a static device that transfers energy between two circuits without altering the frequency. Working on alternating current (AC), they are based on the principle of mutual induction. Generating power at a lower voltage level is cost-effective, but the transmission of power in this manner significantly increases line losses. Using a power transformer assists in balancing the voltage level and consequently decrease line losses..

[Audio] Electrical power transformers enable us to convert low-level power to a higher voltage level for efficient power transmission, reducing I2R losses and lowering the capital cost of the system while improving the voltage regulation of the system. However, it is imperative to step down the high voltage power to the desired level at the receiving end. Clearly, electrical power transformers are integral to power transmission..