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