What is the appropriate connection for a transformer rated at 4160/7200Y-120/240 when connecting to a 4160 volt 3-phase 4-wire system?

For a transformer rated at 4160/7200Y-120/240 when connecting to a 4160 volt 3-phase 4-wire system, a delta connection is appropriate due to the nature of the system and the requirements of phase voltage and grounding.

When connecting a transformer to a 3-phase system, the configuration—wye or delta—affects how phase voltages are managed and how load balancing occurs. In a wye configuration, the line voltage is √3 times the phase voltage, which can be advantageous in certain situations, particularly in balanced loads and for providing a neutral. However, since the transformer’s primary side is rated for 4160 volts, using a delta connection helps keep the line voltage directly at 4160 volts, which aligns perfectly with the system’s voltage rating.

The delta connection is capable of handling three-phase loads effectively and provides better phase-to-phase voltage stability, which is crucial for larger systems with higher power requirements. It also offers redundancy; if one phase fails, the remaining two still carry the load, ensuring greater reliability in the system.

The other connection options, such as series or parallel, do not apply in this context for three-phase transformer connections. Series is not feasible for three-phase systems