In star-connection motor speed is slow due to 1/√3 of the voltage. In delta-connection motor speed is high because each phase gets the total of the line voltage. Phase voltage. Phase voltage is low as 1/√3 times the line voltage. Phase voltage is equal to the line voltage. Number of turns.
Phase current and line current for star connection is equal to each other. Line current is √three times of phase current for delta connections. Speed as starters. Star connected motors are usually slower as they get 1/√3 rd of the voltage. Delta connected motors are usually faster as they get the full line voltage. Here you can learn the fundamentals and operation of star-delta starters. When an induction motor is started directly online, it tends to draw a starting current ranging between 6 to 10 times its normal full load current. It can result in voltage sags. A star-delta starter can help to reduce this starting current by 33%. Three-phase Wye(Y) Connection. Initially, we explored the idea of three-phase power systems by connecting three voltage sources together in what is commonly known as the “Y” (or “star”) configuration. This configuration of voltage sources is characterized by a common connection point joining one side of each source. (Figure below) An example delta-wye transformer schematic. A delta-wye transformer is a type of three-phase electric power transformer design that employs delta-connected windings on its primary and wye/star connected windings on its secondary. A neutral wire can be provided on wye output side. It can be a single three-phase transformer, or built from three Star provided low torque while Delta provides high torque. Star winding is required to detect ground fault currents in the power system.To balance mechanical forces in generator stator, otherwise, it may fly away on faults.Delta stabilized voltages on system faults, trap third harmonics and close zero sequence currents during earth faults Dst5XNo.