Test 2-2

Kilovolt amp being drawn off a transformer can be found by multiplying secondary voltage times secondary amperage and then dividing by

1000

The transformer ratio is 10 to one the secondary voltage is 120 V in the primary voltage is

1200 V

The most common dual voltage distribution transformer is rated at

14,400x7200 120-240

While inspecting a transformer prior to installation if there is a slash between the primary voltages the transformer should have __________ primary bushing and is suitable for a delta primary connection

2

The secondary amperage available on a 25 kVA transformer at 120 V is

208 amps

A spot load check on a transformer finds a lead with 110 V and 105 amps, B lead with 114 V and 95 A what is the exact kVA being taken off the transformer

22KVA

A transformer that is energized but under no load can draw as much as __________ of the current taken in by loaded transformer of the same size

5%

If a load test was done on a transformer and the load on A conductor was the same as the load on B conductor the condition would be referred to as

A balanced load

An isolation link or current limiting fuse in an underground transformer is

Another name for the replaceable fuse

If two transformers are connected in parallel and a primary fuse blows on one of the transformers the other transformer will

Backfeed the one with a blown fuse

If you hold a CSP's handle in the C position on a permanent fault the secondary breaker will

Close

Medium and large size transformers use _______ type wire for a more compact and solidly built coil which also provides better conductivity for the heat to flow out of the windings

Compacted round copper

The initials CSP on a transformer means

Completely self protected

If you have installed several 120 V security lots and need the total capacity of the transformer you should

Connect the coils in parallel

The strength of a electromagnetic field in a transformer is dependent on the ease of which the core is magnetized, the amount of current flowing and the _____________?

Construction material used to build the frame and internal supports of the transformer

A typical distribution transformer consist of a

Core and coil assembly

To vector a three phase system it is essential to establish a ________ of the phases

Fixed reference

The voltage level that can flash over the outside of equipment such as an insulator is called the ___________ level

Flashover insulation

KVA rating of a transformer represents _________?

Full load output

When using test instruments the main reason for the increase in the use of digital electronic technology is

Greater measuring capability

One problem with small three phase voltage unbalances is that they cause

Hi current unbalances

When paralleling two transformers the __________ of the two transformers must be within 107.5% to 92.5% of each other

Impedance

As the temperature drops below 30°C a transformer kVA rating __________?

Increases by 1% for each degree

The four internal parts of a distribution transformer are primary windings, secondary windings, iron core, and

Insulation

Industry standards for electrical transformers call for the H1 terminal to be located on the

Left side when facing the secondary

The purpose of forming a loop in the transformer lead and inserting the lead into the top of the terminal is the

Looping creates greater clearance from the tank to make connections

The length of a vector line is proportional to the

Magnitude

A test instrument that is used to test for insulation breakdown is the

Megohmeter

A transformer change is the voltage and current from one level to another because of the

Number of turns in each coil

The electrical worker installing the transformer should check the tap change your position before it is put into service unless otherwise instructed the tap setting must always be placed

On full winding (100%)

If a transformer is equipped with a taps changer it must never be

Operated while the transformer is energized

The main reason meter fuses blow (when the meter has fuses) is

Overcurrent

Lockout tag out is normally removed by the __________ other than in an emergency situation

Person who installed it

Graphical illustrations using vectors can easily show the following transformer qualities. Transformer output voltages have a magnitude, direction, phase sequence, and __________?

Phase angle

You can get 480 V out of two 120/240 V transformers by

Removing the grounding straps connecting the secondary in series and paralleling the primary side

When performing a polarity test on a single phase transformer the voltmeter rating on a subtractive transformer will be the _______ source voltage

Same

A voltage indicator may not detect the presence of voltage in a wire that is

Shielded

When working on a CSP transformer it is highly recommended that before work is performed on a deenergize secondary

The primary lead be taken off the line

A transformer equipped with tap changes the ____________ of the secondary output

Turns ratio

A ________ reduces the risk of violent transformer failure when it is in series with the cut out

Voltage limiting fuse

The electrical worker who is familiar with the vector ________ can plot any three phase system in 30° increments

Wheel

The most common use of a dual voltage transformer is

When I utility has two different distribution voltages

With a CSP transformer the primary fuse link _______?

Will not deenergize the primary lead from the transformer to the line

The H2 terminal on a single bushing transformer is solidly connected to the

X2 terminal

Primary voltage can be determined by multiplying transformer turns ratio by the

secondary output voltage