2-2

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

The initials CSP on a transformer mean ?

Completely self protected

If you have installed several 120-volt security lights and need the total capacity of the transformer, you should?

Connect the coils in parallel

A ___?___ reduces the risk of violent transformer failure when it is in series with the cutout.

Current limiting fuse

To determine the power being drawn from a transformer, use a multi-meter to find the voltage across and the current through the secondary coils. With these values and the formula, kVA= __?___ , a spot check of transformer power will be found

E x 1 / 1000

Atypical distribution transformer consists of an ___?___

Electric cooling fan

To vector a 3-phase system, it is essential to establish a ___?___ of the phases.

Fixed reference

The Electrical Worker installing the transformer should check the tap changer position before it is put into service unless otherwise instructed. The tap setting must always be placed ___?___

Full winding (100%)

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 3-phase voltage unbalances is they cause

High current unbalances

Kilovolt-ampere (kVA) rating of a transformer represents ?

Impulse/insulation of the level of the secondary coils

T'heH, terminalonasinglebushing transformer is solidly connected to the ? .

Inside of the tank

One requirement of the 1996 Migratory Bird Treaty Act regarding new transformer installations to protect birds from electrocution is to ?

Install bushing covers

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 prevents water from getting into the connection

When performing a polarity test on a single-phase transformer, the voltmeter reading on a subtractive transformer will be ___?___ the source voltage.

Lower than

The length of a vector line is proportional to the ___?___

Magnitude

Polarity tests should be performed on a transformer with a missing or damaged nameplate and the polarity ?

Marked with a white dot near H1 and X1 on the transformer case

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

Megohmmeter

A transformer changes the voltage and current from one level to another because of the ?

Number of turns in each coil

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

Number of turns in the winding

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

Open

If a transformer is equipped with a tap changer it must never be ___?___

Operated while transformer is energized

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

Over current

Lockout/tagout isnormally 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 magnitude, direction, phase sequence, and ?

Phase angle

When working on a CSP transformer, it is highly recommended that before work is performed on a deenergized secondary ___?___

Primary lead be taken off the line

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

Secondary output voltage

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

Shielded

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

Square and rectangle

A transformer equipped with taps changes the ___?___ of the secondary output.

Turns ratio

The Electrical Worker who is familiar with the vector_?_ can plot any 3-phase system in 30° increments.

Wheel

The most common use of a dual-voltage transformer is ___?___

When a utility has two different distribution voltages

With aCSP transformer, the primary fuse link ___?___

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

You can get 480 volts out of two 120/240-volt transformers by ?

removing the grounding straps, connecting the secondary in series, and paralleling the primary side

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

1,000

The transformer ratio is 10:1. The secondary voltage is 120 volts, and the primary voltage is ?

1200v

The most common dual-voltage distribution transformer is rated at ?

14,400 x 7200 - 120/240

While inspecting a transformer prior to installation, if there is a slash (/) between the primary voltages, the transformer should have ___?___ primary bushing(s) and is suitable for a

2

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

208a

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

5%


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