In star connection when two phase is short,it work as single phase system. In delta when one phase is open ,it work as a single phase.
An open delta connection is a delta connection with one phase removed, but still supplied with three line conductors. An open wye is a wye connection with one phase removed, supplying a three line conductors and a neutral conductor. An open-delta/open-wye is a method of providing a reduced-load three-phase supply using just two single-phase transformers, rather than the preferred method of using three single-phase transformers.
A star connection is where the three phase nonpolarities are tied to a single point, and very often grounded. A delta connection is where the nonpolarity of one phase is tied to the polarity of another phase, forming a greek delta shape. If measuring from polarity to nonpolarity on a single phase, in the star formation you are looking at L-N voltages; in the delta connection, you are looking at L-L voltages (L-N voltages * square root of three).
To terminate a 3 wire wye motor to a 3 phase delta connection you need a 3 phase transformer to convert from delta to wye. Do not lift the common neutral connections inside the motor and rewire for delta, because the voltages will be wrong.
Star and delta connection
Line current = 1.732 x Phase CurrentCommentOnly for balanced loads.
normally delta connection wired in 3 phase induction motor. during starting wiring is in Star and after running normal speed changeover to delta .beacause starting time its phase voltage equals less root3 times of line voltage ,line current and phase current equals. in Delta phase voltage and line voltage equals, and phase current equals root3 times line current
the connection here meant for the connection of windings in three core or limbs of a transformer. it might be delta or star connected.
A delta connected appliance can be connected to a 3-phase system by leaving the neutral unconnected. The appliance must be properly earthed.
The star connection has three phase terminal leads and one neutral lead. In case of delta connection it has got three phase terminal leads. the star connection is generally represented by Mercedes symbol with neutral line drawn from the mid point. The delta is represented like a triangle symbol with noneutral line shown.
The power of all three phases can be transmitted on three conductors.A star connection, as opposed to a delta, provides a grounding reference. Also, for ground faults on the secondary (assuming no delta third winding, or source third winding) will be a direct ratio similar to phase faults, instead of 57%. Another reason is to avoid the inherent phase shift involved in a delta/star configured transformer.Another AnswerA 'star-connected' secondary is the standard European connection for a three-phase distribution transformer, as it provides a line voltage of 400 V together with a phase voltage (i.e. line to neutral) of 230 V.
Show digram 3 phase motor 110 and 220
One must check the design of the transformer windings. STAR - Delta or Star to star or Delta - star or Delta Delta. Wiring must be done accordingly.