Delta connection Ph3:3 1g Hand control of excitation is difficult so use is made of an automatic voltage regulator (AVR). The AVR consists basically of a circuit fed from the alternator output voltage which detects small changes in voltage and feeds a signal o an amplifier which changes the excitation to corrected the voltage. Stabilising features are also incorporated in the circuits to avoid hunting"(constant voltage fluctuations)or overcorrecting. Various designs of AvR are in use which can be broadly divided into classes such as carbon pile types, magnetic amplifiers, electronIc types, etc The statically excited alternator has a static excitation system instead of a d.c.exciter This type of alternator will more readily accept the sudden loading by direct on-line starting of large squirrel cage motors. The static excitation sy stem uses transformers and rectifiers to provide series and shunt components for the alternator field, that is, it is compounded. Brushes and sliprings are used to transfer the current to the field coils which are mounted on the rotor. The terminal voltage from the alternator thus gives the extra excitation to give a steady voltage under any load condition. The careful matching of components provides a system which functions as a If regulator of voltage. Certain practical electrical problems and the compensation necessary for speed variation require that a voltage regulator is also built into the system The brushless high speed alternator was also developed to eliminate d.c. exciters with their associated commutators and brushgear. the alternator and exciter rotors are on a common shaft which also carries the rectifiers. The exciter output is fed to the rectifiers and then through conductors in the hollow shaft to the alternator field coils. An automatic voltage regulator is used with this type of alternator From "Introduction to Marine Engineering",D. A. Taylor, 1983)Delta connection Fig. 3 Star and delta three-phase connections Hand control of excitation is difficult so use is made of an automatic voltage regulator (AVR). The AVR consists basically of a circuit fed from the alternator output voltage which detects small changes in voltage and feeds a signal o an amplifier which change s the excitation to corrected the voltage. Stabilising features are also incorporated in the circuits to avoid “hunting”(constant voltage fluctuations) or overcorrecting. Various designs of AVR are in use which can be broadly divided into classes such as carbon pile types, magnetic amplifiers, electronic types, etc. The statically excited alternator has a static excitation system instead of a d. c. exciter. This type of alternator will more readily accept the sudden loading by direct on-line starting of large squirrel cage motors. The static excitation system uses transformers and rectifiers to provide series and shunt components for the alternator field, that is, it is compounded. Brushes and sliprings are used to transfer the current to the field coils which are mounted on the rotor. The terminal voltage from the alternator thus gives the extra excitation to give a steady voltage under any load condition. The careful matching of components provides a system which functions as a self regulator of voltage. Certain practical electrical problems and the compensation necessary for speed variation require that a voltage regulator is also built into the system. The brushless high speed alternator was also developed to eliminate d.c. exciters with their associated commutators and brushgear. The alternator and exciter rotors are on a common shaft, which also carries the rectifiers. The exciter output is fed to the rectifiers and then through conductors in the hollow shaft to the alternator field coils. An automatic voltage regulator is used with this type of alternator. (From “Introduction to Marine Engineering ”, D. A. Taylor, 1983.) Star connection