Math
Connections
Open Delta
Misc
Misc
100

A wye-delta transformer has a primary line voltage of 7200v and a secondary line voltage of 480v, what is the turns ratio?

8.66:1

100

A wye-delta transformer has its_____connected as a wye and its_____ connected as a delta

Primary,secondary

100

In open delta with single-phase loads, the higher leg must be identified by 

using orange wire and tagging

100
Closing the ___ permits more power to be supplied for the operation of three-phase loads

delta

100

What functions are performed by dialectic oil?

provides cooling, acts as an insulator, prevents moisture formation

200
A wye connected secondary has a phase voltage of 277.14v, what is the line voltage?

480v

200

a wye-delta transformer has its_____ connected as a delta and its_____ connected as a wye

primary, secondary

200

When using an open delta with a center-tapped transformer, one wire is the high leg. The high leg is the one that 

has the highest voltage

200
What type of connection involves the use of two transformers to supply three-phase power?

T connection

200

In a T connection, how much is it preferred for the teaser transformer to contain?

86.6%

300

A delta-wye transformer has a turns ratio of 9:1, the primary line voltage is 3600v, what is the secondary line voltage?

692.8v

300
In three phase transformer connections, the primary leads are labeled with the letter __ and the secondary leads are labeled with the letter __?

H;X

300

An open delta connection is made by using ___ single phase transformers.

Two
300
What connection is used primarily for grounding purposes? 

Zig-zag connection

300

What is used to convert three-phase power into two-phase power using two-single phase transformers?

Scott connection

400

A wye-delta transformer has a primary voltage of 7200v and a secondary voltage of 360v, what is the turns ratio?

11.55:1

400

If three-phase transformation is needed and a three-phase transformer of the proper size and turns ratio is not available, three single-phase transformers can be connected to form a __

Three-phase bank
400

An open delta transformer is assembled from two 50 kVA transformer. The output power of the open delta is__

86.6 kVA

400
Which connection is mainly used to establish a neutral point for the grounding of fault currents?

Zig-Zag connection

400

Which connection is often used with rectifiers to produce a smoother DC output voltage?

Six-phase connection

500
A wye-delta transformer has a secondary phase voltage of 480v, a Delta connected load has a resistance of 12 ohms in each leg, what is the current in each load leg?

40A

500
When connecting three transformers for three-phase use with a delta secondary, a voltage test should be done before closing the secondary. The correct voltage reading is ___
Zero volts
500

an open delta transformer is assembled from two 150 kVA transformers. The output power of the open delta is __ 

259.8 kVA

500
In a T connection, the main transformer must contain a center or what percentage tap for both primary and secondary windings? 

50%

500
When making the T connection, the main transformer is connected directly across the ___ 

Power line

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