NLC FINAL TRANSFORMER

Which of these statements about a wye-wye bank is true?

• The “lighter” transformer is larger in KVA than the other two

• The industry standard is to leave the x2 idle when connecting the coils in parallel

• Each of the three transformer provides one hot leg to deliver three-phase power

• When connecting wye-wye, you must float the wye point

Which piece of test equipment checks the transformer coil for insulation damage?

• Turns ratio tester ( TTR)

• Continuity test

• Transformer last check

• Megger

System - 12,000

Nameplate - HV 12,000/20,800Y ---LV 120/240

KVA - 15 and 25

Service - 120/240 - 3 phase

If connected properly, what will the voltage be between lighter x1 and power x1?

• 120 volts

• 416 volts

• 208 volts

• 240 volts

The phase current is 1.73 times higher than a coil current in a _____ connection bank

• Wye

• Delta

• Y

• Neutral

Which arrow is pointing at the pressure relief valve?

• A

• B

• C

• D

Which of these definitions best explains impedance?

• The direction of current flow through the two coils

• It is the process by which oil circulates, cooling the core/coil assembly

• Expressed in percentage, it is the comparison of the number of turns between the windings

• Total opposition to current flow, caused by the transformer itself

Which of these connections is the correct one?

• A

• B

• C

• D

The system voltage is 1.73 times higher than the coil voltage in a ___ system

• Wye

• Delta

• Neutral

• Phased

If connected correctly, using transformers of different______ will work electrically but can cause

confusion for lineworkers who may need to work on the transformer bank in the future.

• Polarity

• Circuit voltages

• Kva ratings

• Transformer voltage ratings

System - 12,000

Nameplate - HV 12,000/20,800Y ---LV 120/240

KVA - 15 and 25

Service - 120/240 - 3 phase

Where will the x2 on the "power" transformer connect?

• Leave idle

• System neutral ( N)

• Conductor ( P)

• Conductor ( H)