in This rectifier unit is shown clearly at the end of the shaft in Fig. Brushless Excitation System consists of two major parts: Pilot Exciter and Main Exciter. 5.17. Brushless Excitation System is a technology for providing the field current to the Synchronous Generator without using Slip Ring and Carbon Brushes. GTC & Code of Conduct; Imprint; Data Protection; Follow us. If you wish to opt out, please close your SlideShare account. As this method of Excitation i.e. The scheme therefore allows the speed of the wind turbine to be varied to obtain more efficient turbine operation at different wind speeds. The amount of excitation required depends on the load current, load power factor and speed of the machine. If the machine is driven faster than the synchronous speed by an engine or other prime mover, the machine torque reverses and electrical power is deliv- ered by the machine (now acting as a generator) into the connected circuit. As this method of Excitation i.e. Why? Email: In Brushless excitation system PMG (mounted on the main shaft at non driving end) generates 220volts, 400hz ac power. As this method of Excitation i.e. I think, no option for online maintenance. The main and the pilot exciters can be driven either by the main shaft or separately driven by the motor. Industriestrasse 26 Brushless Exciter is normally air cooled. Commentdocument.getElementById("comment").setAttribute( "id", "a42c33a7ca9dbe336d3433d3708f2785" );document.getElementById("a0868ac6d7").setAttribute( "id", "comment" ); Subscribe to our mailing list and get interesting stuff and updates to your email inbox. The pilot exciter is a shaft driven permanent magnetic generator having rotating permanent magnets attached to the shaft and a 3-phase stationary armature, which feeds the main’s exciter through 3-phase full wave phase controlled thyristor bridges. Your email address will not be published. The output of the AVR drives a dc current If through the pole windings of the exciter, which are mounted in a stator frame. The induced voltage in stator winding is nothing but the output voltage of generator. Voltage produced by this source is just a control D. C. signal to drive the field of main excitor. Brushless Excitation System is a technology for providing the field current to the Synchronous Generator without using Slip Ring and Carbon Brushes. Excitation System of a Synchronous Machine, Starting Methods of a Single Phase Induction Motor, Two Wattmeter Method of Power Measurement, Difference Between Physical and Chemical Change, Difference Between Alpha, Beta and Gamma Particles, Difference Between Electrolytes and Nonelectrolytes, Difference Between Electromagnetic Wave and Matter Wave, Difference Between Kinetics and Kinematics, Difference Between Synchronous and Asynchronous Counter, Difference Between Analog and Digital Signals, Difference Between Stationary and Progressive Waves, Difference Between Positive and Negative Feedback. See our User Agreement and Privacy Policy. The voltage regulator receives voltage and reactive current feedback provided by potential and current transformers to provide voltage and reactive current feedback. For each arm of Diode, two fuses are connected as shown in the Schematic diagram of the Brushless Excitation System. 5314 Kleindöttingen, Tel. -Working & Types of UPS Explained. It is claimed that the performance of this system is comparable to a machine using a permanent-magnet exciter. Armature winding of PMG is a stationary part which is mounted on Stator. See the schematic diagram of Brushless Excitation System. Yamnampet, Ghatkesar, Hyderabad - 501301 The permanent magnet exciter produces 400 Hz, 220 V AC supply. The AC excitation system consists of an alternator and thyristor rectifier bridge directly connected to the main alternator shaft. (An Autonomous Institution) You can change your ad preferences anytime. Thus when rotor rotates, the filed flux created by Permanent magnet will also rotate and as Armature is stationary, there will be flux linkage in the Armature winding of PMG and an EMF will be induced across the terminals of Armature of Pilot Exciter. Although some generators are still produced with brushes and sliprings to provide the rotor current as illustrated in Fig. This output is rectified by using rotating rectifiers.This DC current is fed via conductors to the center of the rotor shaft and it is carried by a special lead bar in the hollow shaft area under the bearing journal, which is then applied to the main generator field winding.