Interlocking Components in Electrical Drives

Interlocking Components in Electrical Drives: Sensing of signals required for speed and current control loops. Sequencing and interlocking operations are explained in the previous section, whereas this section discusses components used in interlocking and sequencing operations, and protection. It should be noted that signals for Interlocking Components in Electrical Drives and sequencing operations must be […]

Electrical Drive Systems

Electrical Drive Systems: Each Electrical Drive Systems is different from other Electrical Drive Systems. However, there are some common features associated with all Electrical Drive Systems. To understand them it is good enough to consider few examples. This approach has been adapted here. Normally, a Electrical Drive Systems receives its incoming ac supply from a […]

Measures for Energy Conservation in Electrical Drives

Measures for Energy Conservation in Electrical Drives: Following Measures for Energy Conservation in Electrical Drives: Use of efficient semiconductor converters. Use of efficient motors. Use of variable speed drives. Energy efficient operation of drives. Improvement of power factor. Using a motor of right rating. Improvement of quality of supply. Use of single- to three-phase semiconductor […]

Power Factor Improvement Methods

Power Factor Improvement Methods: There are many drives which operate at a low power factor. Some of Power Factor Improvement Methods are: An induction motor direct on line. ac-dc diode rectifier and line commutated thyristor converter fed dc motor and variable frequency ac motor drives. ac regulator fed induction motor drives. Induction motor drive with […]

Energy Efficient Operation of Drives

Energy Efficient Operation of Drives: In many Energy Efficient Operation of Drives applications involving constant speed operation, induction motors operate under no load or light load for prolonged periods, such as in pressing machine, conveyors, rock crushers, centrifuges, drill presses, wood saw and, some machine tools. In such applications, saving in energy can be achieved […]

Application of Variable Speed Drives

Application of Variable Speed Drives: Several drives are driven at constant speeds by induction or synchronous motors, although operation of Application of Variable Speed Drives could lead to saving of substantial amount of energy. Such practice was adapted in the past because of nonavailability of efficient methods of speed control of induction and synchronous motors. One […]

Use of Efficient Semiconductor Converters

Use of Efficient Semiconductor Converters: Prior to development of Use of Efficient Semiconductor Converters, inefficient power modulators were employed in several applications. While replacement of these power modulators by the semiconductor converters in appropriate applications brings about substantial amount of energy saving, the cost of replacement can be recovered in a short period ranging from […]

Energy Losses in Electrical Drive System

Energy Losses in Electrical Drive System: Energy conservation in electrical drive is achieved by reduction of losses in its various parts. Typical Energy Losses in Electrical Drive System include the following: 1. Electrical transmission losses: These losses depend on the drive power factor and harmonics in the line current. 2. Conversion losses in the power […]

Diesel Electric Traction System

Diesel Electric Traction System: Because of high initial cost, electric traction is justified only where there is sufficient volume of traffic. Diesel Electric Traction System is preferable where the traffic is limited. Boundary between these two alternatives depends on several factors such as initial cost, running cost, amount of traffic, maintenance etc. Diesel Electric Traction […]

Polyphase AC Motors for Traction Drives

Polyphase AC Motors for Traction Drives: Polyphase AC Motors for Traction Drives – Advantages of ac motors over dc we already know. Because of negligible maintenance, ruggedness and higher power per unit weight or volume, the squirrel-cage induction motor is ideally suitable for traction applications. Because of higher efficiency, and simpler and cheaper inverter, compared […]

DC Traction

DC Traction using Semiconductor Chopper Controlled DC Motors: Chopper control has replaced resistance control in all dc traction schemes, such as 1500 V dc main line and suburban traction, 750 V dc underground traction and electric buses. The chopper control has following additional advantages over the resistance control: Regenerative braking can be carried out almost […]