Category: Motor Control

Static Scherbius Drive Circuit Diagram

Static Scherbius Drive Circuit Diagram: A basic scheme of a Static Scherbius Drive Circuit Diagram converter cascade, that is employed for recovery of slip power in electrical form itself, is given in Fig. 11.42. For achieving both subsynchronous and supersynchronous speed control, converters C1 and C2 must be fully-controlled thyristor bridges, one functioning at slip […]

AC Motor Control

AC Motor Control: AC Motor Control – The only way to control the speed of a synchronous motor is to control the input frequency and voltage such as to keep V/f constant. The induction motor, on the other hand, can be controlled by the following means: 1. Stator Voltage Control This is applicable for small […]

DC Motor Control through Choppers

DC Motor Control through Choppers: DC Motor Control through Choppers – For controlling a dc motor operated from dc supply, the dc voltage level must be controlled. Examples can be cited of subway drives, trolley buses or battery-operated vehicles. Conventional methods of converting a fixed-voltage dc source to a variable-voltage dc source are: Resistance Control […]

Three Phase Converters

Three Phase Converters: Large-kW motors are fed from 3-phase supply through three Phase Converters. In a Three Phase Converters, the ripple frequency of the motor terminal voltage is higher than that in the single-phase converter, as a result the filtering requirements for smoothing out the motor current are less and the current is mostly continuous. […]

DC Motor Control through Converters

DC Motor Control through Converters: DC motor control is conveniently and efficiently achieved by phase-controlled converters wherein the ac input voltage is converted to a controlled dc output. The commutation process, the transfer of current from one thyristor to the other, in these converters is the inexpensive natural or line commutation. As, an incoming thyristor is […]

Thyristor Motor Control

Thyristor Motor Control: Thyristor Motor Control – A variety of thyristor control circuitry has been devisd for use in motor control depending upon the type of supply (ac/dc) and the type and size of the motor. For dc motor control, controlled dc power from a constant voltage ac supply is obtained by means of controlled […]

AC DC Converters

AC DC Converters: AC DC Converters – The naturally commutated phase-controlled converter is a common type of controlled power electronic converter which has reigned supreme for the last 30 years. Above a few tens of kW, three-phase rectifiers are used, the most common arrangements being the fully/semi-controlled bridges. Semiconverter systems, including a free-wheeling diode give […]

Power Converters

Power Converters: Power Converters – Since the introduction of the thyristor, the converter technology has progressed through intense technological evolution for the last four decades and has emerged into a multidisciplinary technology. With basic thyristors, the converters can be naturally commutated or force commutated type. In a naturally commutated converter, the circuit has a natural […]

Block Diagram of Electrical Drive System

Block Diagram of Electrical Drive System: Electrical Drives – Invention of thyristor led to emergence of semiconductor drives in early sixties. The improvements in converters and development of new drive-control strategies, such as field oriented (or vector) control of ac drives, sliding-mode control, energy saving strategies, etc. brought about another revolution in drive technology and […]

Comparison of Modern Devices

Comparison of Modern Devices: Comparison of Modern Devices – SITH is the largest power device and SIT is the highest frequency device in the present state of technology. It is not possible to compare exactly since devices with compatible power ratings are not simply available. SIT is a very high frequency high power device, but […]