Fundamentals of Electrical Drives

CSI Squirrel Cage Induction Motor Drive: Performance and operation of CSI induction motor drive is already explained . Figure 10.23 shows details of the traction drive of CSI Squirrel Cage Induction Motor Drive. In a multistage converter ac is converted into dc with sequence control to improve converter power factor and to reduce harmonics produced […]

Load Commutated Inverter Fed Synchronous Motor Drive: Load Commutated Inverter Fed Synchronous Motor Drive is shown in Fig. 10.22. The inverter is a current source inverter employing thyristors T1 – T6. The commutation of inverter thyristor is done by the voltages induced in armature of the synchronous motor. A chopper is used to obtain a variable dc

PWM VSI Induction Motor Drive: PWM VSI Induction Motor Drive for traction is shown in Fig. 10.21. A pulsewidth modulated voltage source inverter converts dc into variable frequency and variable voltage ac, which is then fed to induction motors. Each motor coach of a suburban train may employ a single inverter feeding several squirrel-cage motors

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 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

Semiconductor Converter Controlled Drives: These are now widely used both in ac and dc tractions involving dc and ac motors, and the conventional drives have all become outdated, and will be phased out in near future. The Semiconductor Converter Controlled Drives have several advantages. Some of their common advantages are listed below: High efficiency. Low

Conventional DC and AC Traction Drives: The commonly used Conventional DC and AC Traction Drives are The dc Traction Drives Employing Resistance Control: The dc traction drives employing resistance control are: 1500 V dc traction on Bombay-Igatpuri-Pune section for main line and Bombay suburban 750 V dc traction in underground trains at Calcutta. 550 V

Traction Motors: Motors Employed in Traction : Earlier, dc series motor was widely used in Traction Motors. It has high starting torque and capability for high torque overloads. With an increase in torque, the flux also increases; therefore, for the same increase in torque, the increase in motor current is less compared to other motors.

Features of Traction Drives: Various Features of Traction Drives are: 1. Large torque is required during start and acceleration in order to accelerate the heavy mass. 2. The motor is subjected to torque overloads during acceleration and when negotiating up gradients. 3. Because of economic reasons single phase supply is used in ac traction. Indian

Traction Drive Rating and Energy Consumption: Traction Drive Rating and Energy Consumption – The speed-time curve of Fig. I0.6(a) is reproduced in Fig. 10.9. For simplification in calculations, it is approximated by a trapezoidal curve having constant values for acceleration and deceleration. As the area beneath curve represents distance covered, the area of trapezoidal curve