Transformer Connections

What are two common ways of connecting loads and transformers in 3-phase systems? (select all that apply)

• delta

• wye

• delta-delta

• delta-wye

The majority of dwellings are wired with what type of service with what available voltages?

• 3-phase, 4-wire, 480/277

• 3-phase, 4-wire, 120/208

• 1-phase, 3-wire, 120/240

• 1-phase, 2-wire, 120

In a 3-phase, wye-connected system, the voltage values must be added vectorially because the coils are set 120 electrical degrees apart. In such an arrangement, the phase-to-phase voltage is obtained by multiplying the phase-to-neutral voltage by what multiplier? (select all that apply)

• 0.58

• 3.14

• 1.73

•  $\sqrt{3}$  

The delta wiring configuration places each winding across the phase to phase source voltage. Therefore, the voltage across the winding will be equal to what value?

• the winding voltage multiplied by 125%

• zero

• the line voltage multiplied by 1.73

• the line voltage

The transformer depicted in this photo is comprised of which of the following?

• A three-phase coil

• Three single-phase coils

• An oil-immersed coil

• One single-phase coil

What type of connection if often used for distribution where a four-wire secondary distribution circuit is required?

• Wye-Wye

• Wye-Delta

• Delta-Wye

• Delta-Delta

A 3-phase connection that has one end of each coil connected together and the other end of each coil left open for external connections is known as what?

• Delta

• Wye

• Flying V

• Auto

A 3-phase connection method that has the wire from the ends of each coil connected end-to-end to form a closed loop is know as what?

• Wye

• Delta

• Flying V

• Auto