2-2

The resistance of test leads must be less than ? .

1 Ω

The red light on a CSP ? after the load decreases.

Stays on

The emergency control handle on a CSP transformer should be used as a ? .

temporary fix to an overload situation

With the coils connected in series, a dual-voltage transformer will operate on __?__

the higher of the two voltages

All other units of measure are defined and compared to the four basic measurements of length, ? .

weight, time, and temperature

On a fully loaded 25 kVA transformer, the drop leads would normally be ? stranded copper.

#2

On a CSP transformer carrying 250 amperes that has tripped, using the emergency handle will give ? Hrs of power.

1.5

When paralleling transformers, the voltmeter must read zero or not over ? .

10 v

When a 3-phase current unbalance exceeds ? , a test for voltage unbalance should be performed.

10%

AC at 60 hertz per second increases and decreases in value ? times per second.

120

An electric provider is allowed to have extreme voltages on a 120-volt service of 106 volts low and ? high.

127

A distribution transformer with taps has its primary in ? .

2 coils

According to U.S. standards, all transformers ? kVA and above in all voltage classes and/or voltage ratings above ? V are subtractive.

200/8660

In all tap settings on a transformer terminal board, ? and ? are always connected together.

3/4

On a 25-kVA CSP carrying 180 amperes, the signal light will be energized after ? Hrs.

3hrs

Recording voltmeters should be set at the customer's service entrance because there may be a ? drop in voltage between the transformer and the customer's service entrance.

4%

Current transformers are installed on single-phase circuits when the current exceeds ? amperes and on 3-phase circuits when the amperage exceeds ? .

400/200

A transformer that is energized but not loaded can draw as much as ? of the current taken in by a loaded transformer of the same size.

5%

Current transformers reduce the current being metered to a value that should not exceed ? .

5A

The primary fuse link of a CSP will operate at ? to ? times the normal current.

8/14

According to this lesson, the U.S. standard for the polarity of single-phase transformers is ? for transformers below 200 kVA with high voltage ratings of 8,600 volts and below.

Additive

Distribution transformers are generally manufactured with ? polarity.

Additive

If a Qualified Electrical Worker has installed several 120-volt security lights and needs the total capacity of the transformer, he or she should ? .

Connect the coils in parallel

Heat in a transformer core is generated because of the ? of molecules.

Constant reversal

Normal types of losses concerning electrical transformers are __?__.

Copper and core

The coil leads B and C emerge above the oil level in the ? position.

Crossed

Of the three ratios governing transformer operation, ? is in the reverse order to the other two.

Current

One problem with small 3-phase voltage imbalances is that they cause high ? imbalances.

Current

Using Watt's Law, when reducing voltage through a transformer, the ? to supply the load.

Current will increase

A tap-changing mechanism works by adding in windings to the secondary side of a transformer.

False

Core-type transformers are best suited for low voltage and high currents.

False

Extra care must be provided to digital test instruments because their movements are susceptible to damage from shock.

False

Grounding is the connection of all exposed, noncurrent-carrying metal parts to the neutral conductor.

False

Impedance is the combination of resistance and current.

False

Removing the grounding strap of a single-phase transformer results in one phase of 480 volts.

False

The high voltage winding is normally placed next to the core to increase EMF.

False

The secondary breaker of a CSP protects it from high voltage surges.

False

The voltage ratio of a transformer is the effective voltage of the primary to the potential voltage of the secondary.

False

Voltage indicators only indicate that voltage and current are present; they do not indicate the actual voltage.

False

n order for a single-phase transformer to produce any secondary voltage, the X2 grounding strap must be in place.

False

Aluminum links or straps are used to make the connections on a transformer terminal board.

Falsw

The ease with which the core can be magnetized is not one of the three things that govern the strength of a transformer's electromagnetic field.

Falsw

Many test instruments include a(n) ? in the current-measuring circuit to prevent damage caused by excessive current.

Fuse

One advantage of voltage testers is that they have a lower impedance (resistance) and draw more current than voltage indicators, which allows them to be used for testing ? .

GFCIs

If a transformer nameplate shows 14,400/24,940 Y, it is suitable for a delta connection because it has full insulation ? .

H2

The lines of force must be ? in order to induce a voltage and cause a current to flow in the circuit.

In motion

A power plant transformer ? the voltage and ? the current on a transmission line.

Increases/reduces

The H2 terminal on a single bushing transformer is solidly connected to the ? of the tank.

Inside

The primary link will remove a(n) ? faulted transformer from the system.

Internally

The ? concentrates and directs the magnetic field and makes transformers possible.

Iron core

The absolute zero scale of centigrade is often called the ? .

Kelvin

As the primary voltage drops, one would ? the percentage on the tap changer to raise the secondary voltage.

Lower

The baked-on insulating compound used in transformer coils prevents ? from getting into the windings.

Moisture dust and dirt

For maximum safety, personal protective equipment and safety requirements for test instrument procedures must be followed, as specified in ? , which is one of several standards.

NFPA 70E

In order to phase in a single-phase transformer, the transformer ? .

Neutral must be connected

The amount of current flowing and the ? are two of the three things that govern the strength of a transformer's electromagnetic field.

Number of turns in the winding

The ? is a federal act that requires all employers to provide a safe environment for employees.

OSHA act

To obtain maximum induction, the coils must be ? and ? so the field is able to cut across the conductors of the other.

Parallel/sufficiently close

A transformer's secondary must be ? when used as part of a 120/208 3-phase bank.

Paralleled

A popsicle stick connector is a(n) ? terminal connector that is squeezed onto the end of the wire and inserted into the secondary terminals of a transformer.

Pin

? is determined by the direction the high-voltage coil is wound in relation to the low-voltage coil winding direction.

Polarity

To close a CSP secondary breaker that has tripped, one must move the indicator to ? and then back to ? .

R/closed

If a transformer was ordered 24,940 Grd Y/14,400, the transformer would have ? insulation at the H2 end.

Reduced

A current transformer should have its ? short-circuited while being installed, or while connected in a circuit with no meter connected to the secondary.

Secondary

Distribution transformers have off-load tap switches, which do not in any way regulate the ? voltage.

Secondary

A dash (-) between the primary and secondary voltages of a transformer is used to ? .

Separate the voltages

Two types of electrical transformer cores are ? .

Shell and core

More heat flows out of transformer windings if ? or ? wire is used in the coils.

Square/rectangular

Large power transformers are generally manufactured with ? polarity.

Subtractive

The primary fuse in a CSP protects the ? from an internal fault.

System

The industry standard for the location of an H1 terminal when facing the ? is the left hand side.

The low voltage aide

A conventional transformer can be used as a primary booster, but it must be marked as a hazard

True

A two-bushing single-phase transformer can be connected to a wye or delta system.

True

AC windings will usually burn out if connected to a DC circuit.

True

Analog test instruments are less accurate than digital test instruments.

True

As the magnetic field in the primary coil increases in strength, the current in the secondary increases.

True

Current flows into a single-phase transformer in the H1 terminal and out the X1 terminal at the same instant.

True

Double-bushing tapped transformers normally have one tap above 100% in order to lower the secondary voltage.

True

The kilovolt-amperes being drawn off of a transformer can be found by multiplying secondary voltage times secondary amperage and dividing the result by one thousand.

True

The primary coils of a dual-voltage transformer can be connected in series or in parallel.

True

When paralleling transformers, both transformers must be connected to the same phases on the primary and on the secondary

True

When using an ohmmeter, the resistance of all components connected in parallel with the component being tested affects, and typically lowers, the resistance

True

Only a meter marked " ? " can be used when taking a measurement on a circuit that includes solid-state components that distort the shape of AC sine waves (motor drives, PLCs, computers, and printers).

True RMS

A transformer rating of 120/240 shows that there is/are ? .

Two secondary coils

The signal word used to indicate a potentially hazardous situation that could result in death or serious injury is the ? .

Warning

Transformer bushings are manufactured using a ? process.

Wet

The internal transformer lead marked D is always connected to ? in an additive transformer.

X1

On a single-bushing transformer, the tank ground is ? .

also the neutral connection of the high voltage winding

The thin, insulated sheets of steel in a transformer core reduce __?__ and __?__.

core loss, heating

On a transformer nameplate, an X between the primary numbers means ? .

either voltage is available but not at the same time

A CSP transformer contains a(n) ? and a ? breaker.

internal HV fuse / secondary

One reason paralleling two small transformers for increased demand is not economical is because the ? , when added together, is/are greater than in one large transformer.

losses of each transformer

The Romans refined distance traveled to a unit of length called the ? .

mile

In-line ammeters require the circuit to be ? so the ammeter can be inserted into the circuit to acquire a reading.

opened

Ohm's Law cannot be used directly on AC circuits because ? .

reactance and resistance oppose current flow

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

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

The metric system adopted the ? as the standard unit of time measurement.

second

The product of the primary voltage and current is equal to the product of the ? .

secondary current and voltage