Deck 19: Alternate Wye and Delta Connections of Transformers

Question 1

For the primary side of the delta bank, coil current equals ____________________ A.

Answer 1

8.33

Question 2

The delta-wye transformer bank is well adapted for stepping up voltages.

Answer 2

True

Question 3

Another name for the open-wye-open-delta connection is the ____________________.

Answer 3

wye-delta with one transformer missing
wye-delta with 1 transformer missing

Question 4

In an open-wye-open-delta connection, the primary winding is connected to two of the three phase conductors, and the common point is connected to the ____________________.

Question 5

What are the advantages of the three-phase transformer?

Question 6

What is the one disadvantage to the use of a three-phase transformer?

Question 7

The open-wye-open-delta transformer connection is sometimes used to deliver small amounts of three-phase power to a secondary load and deliver larger amounts of single-phase power to the secondary load.

Question 8

____________________ leads are brought out when any wye-connected windings are used in a three-phase transformer.

Question 9

How are the secondary coils connected in an open-wye-open-delta transformer connection?

Question 10

What is the difference between "transformer ratio" and "transformation ratio"?

Question 11

What two types of service are available as a result of the three-phase, four-wire secondary system?

Question 12

Three-phase transformers may only be connected in delta-delta and wye-wye.

Question 13

A transformer connected in ____________________ is the type most often used to step down relatively high transmission line voltages (60,900 volts or more) at the consumer's location.

Question 14

The three single-phase transformers used in a delta-wye connection have different kVA capacities.

Question 15

For the primary side of the delta bank, the line voltage and the coil voltage are the same.