Motor Control

Single Phase Bridge Inverter: A serious disadvantage of the half-Bridge Inverter of Fig. 11.46 is that it requires a 3-wire dc supply. This is overcome by the commonly employed Single Phase Bridge Inverter circuit of Fig. 11.48(a) which needs four thyristors and four free-wheeling diodes. The sequence of thyristor gating and the output waveforms are shown […]

Single Phase Half Bridge Inverter | R Load | RL Load | RLC Load: Figure 11.46(a) gives the circuit configuration of a Single Phase Half Bridge Inverter. It has two thyristors and two free-wheeling diodes. Each thyristor is gated at frequency f = 1/T of the ac supply desired. The gating signals of the two

Phase Control of Three Phase Induction Motor: Figure 11.44 shows the schematic representation of Phase Control of Three Phase Induction Motor. Two thyristors are connected in antiparallel in each line. The firing sequence of the thyristors for all modes of operation is 1, 3′, 2, 1′, 3 and 2′ as shown in Fig. 11.45. The

Static Kramer Drive: The Static Kramer drive system which consists of variable-speed drive system shown in Fig. 11.43 consists of a slipring induction motor and a rectifier-fed dc motor. The machines are connected electrically in cascade. The slip power recovery takes place through the rectifier and the auxiliary dc motor. Torque supplied to the load

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

Induction Motor Speed Control Methods: 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 Speed Control, on the other hand, can be controlled by the following means: Stator Voltage Control Frequency Control Slip Control 1. Stator

Basic Principle of Chopper Circuit: A Basic Principle of Chopper Circuit is essentially a thyristor switch in series with the load as shown in Fig. 11.27(a). A shunting diode is provided across the load for free-wheeling the load current when the thyristor is off. The thyristor shown enclosed by a dotted square can be turned-on

Three Phase Semi Converter feeding Separately Excited DC Motor: Large-kW motors are fed from 3-phase supply through three Phase Converters. In a three Phase Semi Converter, 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

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