408 volts x 1.73 = 277 volts is the star ( Y ) point of 3 phase 480V. A transformer connected in a Delta configuration is different than a Y or Star configuration. 277 volts is a voltage that is used in industrial plants usually for lighting. The following link will explain the whole star delta connection. http://www.allaboutcircuits.com/vol_2/chpt_10/6.html
The open Delta or V-Connection transformer is an improvement of the 1 three-phase transformer. The open Delta transformer can restore power in a Delta-Delta three-phase bank when one of the three single-phase transformers, which can be individually disconnected and replaced in case of failure, breaks down. The open Delta transformer then allows functionality to be restored, but at a reduced power of 57.7 of the original power.
not necessarily if the power source is delta the y voltages (or phase to ground) may not be predictable there is 3phase delta with one leg grounded there is 3 phase 240 delta with center of one phase grounded for 120/240 single phase for lights primary on these is all 240 delta y would be 0 120 132 240 or 277 depending on that ground point
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 delta motors start as a Y for 3 phase so the windings that normally see 480 volts see 277V a relay switches to delta then it runs as a normal delta motor the reduces the starting current by about 60% for 3 phase
There are various ways in which you can connect a three-phase transformer's primary and secondary windings, or in which you can connect three single-phase transformers to create a three-phase transformer bank. For example: wye-wye, wye-delta, delta-delta, delta-wye, etc.For each connection, there is a natural phase shift between the primary and secondary line voltages. This is called the angular displacement (or 'phase displacement') of the transformer connection.If you wish to parallel two three-phase transformers, or two three-phase transformer banks, then their angular displacements must be the same (there are also other requirements not relevant to this answer).A vector group is a method of specifying a three-phase transformer (or transformer bank) method of connection and its angular displacement. Transformer connections from the same group can be paralleled. Those in different groups cannot
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.
The open Delta or V-Connection transformer is an improvement of the 1 three-phase transformer. The open Delta transformer can restore power in a Delta-Delta three-phase bank when one of the three single-phase transformers, which can be individually disconnected and replaced in case of failure, breaks down. The open Delta transformer then allows functionality to be restored, but at a reduced power of 57.7 of the original power.
not necessarily if the power source is delta the y voltages (or phase to ground) may not be predictable there is 3phase delta with one leg grounded there is 3 phase 240 delta with center of one phase grounded for 120/240 single phase for lights primary on these is all 240 delta y would be 0 120 132 240 or 277 depending on that ground point
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
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.
Amplitude, frequency/period and phase.
Balanced Star (Wye) Connected Systems:Line Voltage = 1.732 x Phase VoltageLine Current = Phase CurrentBalanced Delta Connected Systems:Line Voltage = Phase VoltageLine Current = 1.732 x Phase Current
star delta motors start as a Y for 3 phase so the windings that normally see 480 volts see 277V a relay switches to delta then it runs as a normal delta motor the reduces the starting current by about 60% for 3 phase
There are various ways in which you can connect a three-phase transformer's primary and secondary windings, or in which you can connect three single-phase transformers to create a three-phase transformer bank. For example: wye-wye, wye-delta, delta-delta, delta-wye, etc.For each connection, there is a natural phase shift between the primary and secondary line voltages. This is called the angular displacement (or 'phase displacement') of the transformer connection.If you wish to parallel two three-phase transformers, or two three-phase transformer banks, then their angular displacements must be the same (there are also other requirements not relevant to this answer).A vector group is a method of specifying a three-phase transformer (or transformer bank) method of connection and its angular displacement. Transformer connections from the same group can be paralleled. Those in different groups cannot
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 delta connected appliance can be connected to a 3-phase system by leaving the neutral unconnected. The appliance must be properly earthed.
why three phase induction motor is delta connected