There is really no advantage, the only purpose of having the variety is for motor manufacturer companies to be able to sell their product to customers if the building's electrical service is of a Delta of Wye configuration.
If you are asking what is the advantage of a motor wound for a Y or Delta configuration over a motor wound for a single phase configuration, then the advantage of the Y or Delta motor is more efficient operation. And in a motor, or in any power application, efficiency is all important.
one windingAnswerA three-phase motor has three phase windings, normally (but not necessarily) connected in delta.
Delta motors should have more starting current than Wye (Star) motors because Delta motors have two windings to take current per phase -- they are wired Phase to Phase. Star motors have only one winding per phase -- they are wired Phase to Neutral.
There is no neutral in a delta connection, because that is the definition of delta, a power configuration where current flows from phase hot to phase hot. The loads are A-B, B-C, and C-A. Contrast this with star, where there is a neutral, and the loads are A-N, B-N, and C-N.
A delta-connected system is described as being a three-phase, three-wire, system, and doesn't have a neutral. But a balanced star (wye) connected load (e.g. a three-phase induction motor) doesn't actually require a neutral.
why three phase induction motor is delta connected
Star and delta connection
One of the three phase contacts in the star contactor could be burned open or just open not allowing the motor to start because of a single phase condition. The time interval between star and delta connections could be small enough that the motor heaters will not catch the single phase condition and trip. When the motor goes into delta (which is now across the line starting) all of the three phase contacts in the contactor close and the motor starts.
If you are asking what is the advantage of a motor wound for a Y or Delta configuration over a motor wound for a single phase configuration, then the advantage of the Y or Delta motor is more efficient operation. And in a motor, or in any power application, efficiency is all important.
one windingAnswerA three-phase motor has three phase windings, normally (but not necessarily) connected in delta.
To shift from a star winding to a delta winding in a three-phase motor, the connections between the windings need to be rearranged. In a star winding, the ends of the windings are connected to a common point (neutral), while in a delta winding, each winding end is connected to the start of the next winding. By physically switching the connections, the motor can be reconfigured from star to delta winding.
The star delta motor starter circuit has to have a control voltage to energize the motor magnetic contractors. A phase failure relay monitors all three phases of the incoming supply lines. The phase failure relay also has auxiliary contacts on it. There are usually two sets of "C" form contacts. The control voltage for the starter circuit must be connected across the normally open (N.O.) contacts of one of these two sets. When the phase monitor is energized these N.O. contacts close supplying the control voltage to the circuitry of the star delta starters. If there is a phase interruption, phase reversal or phase loss, the phase failure relay will de-energize and the N.O. contacts will go back to their de-energized state. If the star delta motor starter is in use at the time, its control circuitry voltage will be lost and the delta motor magnetic contactor will open. The opening of this contactor will disconnect the motor from the failed three phase supply.
Delta motors should have more starting current than Wye (Star) motors because Delta motors have two windings to take current per phase -- they are wired Phase to Phase. Star motors have only one winding per phase -- they are wired Phase to Neutral.
To use a single/one phase motor instead of a three phase motor is possible if you have a three phase power supply as you will only need to tap one of the three phases together with neutral and an earthwire, however to use a three phase motor instead of a single phase will require the provision of three phase power supply.
The three common types of starters used in a three phase circuit are DOL (Direct-On-Line) starter, star-delta starter, and soft starter. DOL starters provide full voltage to the motor upon start, which can cause high inrush current. Star-delta starters initially start the motor in a star configuration to reduce current, then switch to delta for full speed. Soft starters gradually ramp up the voltage to the motor to reduce inrush current and mechanical stress on the motor.
The line current would be the same if the motor were connected in delta. The current can be based on the rule of thumb which says 7 amps must be allowed for a 1-HP single-phase motor on 240 v. A 2.2 kW motor is three times as powerful, and on a three-phase supply of the same voltage (240/415) it would draw 7 amps.
There is no neutral in a delta connection, because that is the definition of delta, a power configuration where current flows from phase hot to phase hot. The loads are A-B, B-C, and C-A. Contrast this with star, where there is a neutral, and the loads are A-N, B-N, and C-N.