Transformers, Ch 4, 5

Front 1

The nameplate provides technical information used to safely:

Back 1

Store, transport, install, maintain, and inventory the unit.

Front 2

When to use the nameplate.

Back 2

1. Prior to installation

2. Ensure primary voltage is chosen

3. Ensure secondary voltage is chosen

4. Ensure impedances are +/- 10%

5. Weight for rigging purposes.

Front 3

Where is the nameplate located on overhead transformers?

Back 3

Lower mounting bracket

Front 4

Where is the nameplate on underground transformers?

Back 4

Inside the door or on the face

Front 5

Always check the nameplate to determine _______ before installation.

Back 5

Proper voltage.

Front 6

Most useful info on a nameplate of a transformer?

Back 6

Voltage ratings, kVA, serial number, polarity, impedance, schematic.

Front 7

Always verify the ________ with an approved voltmeter before connecting the customers load.

Back 7

Secondary voltage

Front 8

The input voltage rating is also the ______.

Back 8

Primary voltage rating

Front 9

The output voltage rating is also the _______.

Back 9

secondary voltage rating

Front 10

The primary coil rating is always the _______ of the two primary voltages listed on the transformer.

Back 10

smaller

Front 11

The book says for an average size home of 6000 watts, what size transformer would be used?

Back 11

10kVA

Front 12

The serial number is used for inventory and:

Back 12

tracking purposes

Front 13

Additive transformers will have x1 on the _____ and subtractive will have x1 on the ______.

Back 13

right, left

Front 14

What is impedance?

Back 14

the opposition of current flow caused by resistance and inductive reactance.

Front 15

If a transformer is 98% efficient, the impedance is ____%.

Back 15

2%

Front 16

A schematic shows the primary and secondary ____________.

Back 16

coils and their relationship.

Front 17

Always verify the _________ voltage with an approved voltmeter before connecting the customer's load.

Back 17

secondary

Front 18

Transformer manufacturers most commonly comply with what standard when designating winding voltage ratings.

Back 18

ANSI Standard C57.12.00

Front 19

When interpreting the coil rating of a transformer, the ________ number is the voltage that needs to be impressed on the primary coil for proper operation

Back 19

smaller

Front 20

When interpreting the coil rating of a transformer, the ________ number referes to the voltage of the system.

Back 20

larger

Front 21

What type of connection is used for phase to phase only?

Back 21

Delta

Front 22

What type of connection is used for phase to ground?

Back 22

WYE

Front 23

The dual voltage switch should only be operated when the transformer is:

Back 23

de-energized

Front 24

How does a dual voltage switch utilize a dual rating on their primary coil.

Back 24

The switch changes the primary coil turns ratio

Front 25

What can be used in-leu of a high-cost voltage regulator to maintain secondary voltage along the line.

Back 25

transformers with tap changers.

Front 26

Taps on transformers must be adjusted when the transformer is ______.

Back 26

de-energized.

Front 27

Depending on the manufacturer, each tap raises or lowers the secondary voltage by___% or ____%

Back 27

2.5% or 4.5%

Front 28

The tap changer is a no load manual switch that is connected to the _______ _______ and increases or decreases the turns ratio of the transformer with each tap setting.

Back 28

primary coil

Front 29

If a tap is raised, the number of turns of the primary coil is ____________, which maintains the output voltage as the primary voltage drops.

Back 29

reduced

Front 30

Polarity is the:

Back 30

direction of current flow

Front 31

additive transformers will have x1 on the _______.

Back 31

right

Front 32

Subtractive transfomers will have the x1 on the ______.

Back 32

left

Front 33

Testing the ________ of a transformer prior to installation is always recommended.

Back 33

integrity

Front 34

Various test can be performed on transformer, which include:

Back 34

continuity testing,

insulation testing,

turns-ratio testing

Front 35

if continuity is proven between the primary and secondary coils, the transformer is ________ and should not be used

Back 35

defective

Front 36

an audible sound should not be heard between the ________________ of a transformer

Back 36

primary and secondary windings

Front 37

What is a TLC meter?

Back 37

transformer last check, used to verify transformers do not have shorted or open windings prior to energizing.

Front 38

What is a megger?

Back 38

a device used for trouble shooting and to test insulation, in electrical cables, wires, or networks