The armature winding of alternator have a six out put terminal, in which three terminal short (make neutral point) and remaining three gives output which are possible only in star connection. So we are connected in star
Alternators are connected primarily in star to achieve the following motives:br /Lesser stress on a rel='nofollow' href="https://www.dieselgeneratortech.com/generator-sets/How-to-Test-The-Insulation-Level-of-Diesel-Generator-Sets.html"insulation/a and Copper saving: Voltage per phase is less for a given line voltage which reduces insulation requirement and this also reduces the number of turns hence copper is also saved.br /Easy protection: Neutral grounding is necessary to allow zero sequence currents to flow to the ground in case of a fault.br /Elimination of harmonics: Star connection facilitates a neutral connection which is instrumental in eliminating triple harmonics.br /No circulating currents: In star connection we don't have circulating parasitic currents like in delta which lead to heating losses.
Since the induced emf in the phase winding of an alternator is directly proportional to the number of turns, a star connected alternator will require lesser number of turns than a delta connected alternator for the same line voltage.
Alternator is connected in star because We know that in star connection Iphase =I line current So current produce in phase( armature winding ) is equal to line Current but in delta connection root 3 I phase =I line current so current line is more than phase cuttent
1. If there is fault current by neutal we can reduce that. As in delta there is no neutralbr /2. Insulation required will be less. As per phase voltage is decreased by root3br /3. Suppression of harmonics..
1.There is a neutral point available to let the current flow through it under unbalance or fault condition 2.In star connection V phase = √3 V line and I line= I phase
In star connection there is a neutral availability if there is any problem . And another one is it reduces the high voltage values.