Random junk Flashcards by Tanner Unknown

What does ELI mean in the saying “ELI the ICE man”

voltage(E) leads current(I) in an Inductive(L) circuit.

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What does ICE mean in the saying “ELI the ICE man”

Current(I) leads voltage(E) in a capacitive(C) circuit.

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Typical voltage of output of power generation station

11-33 KV

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a 35microfarad capacitor is connected to a 120v, 60hz line what is Xc
Hint: Xc=1/(2(pi)(f)(c)

75.79

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Most low voltage breaker manufacturers recommend contacts touch within _____ of each other

1/8”

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How many resistors in a Wheatstone bridge are variable

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What range of impedance levels can modern test instruments take during battery fault tracing?

400K ohms

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do schematic diagrams show physical location of components

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When should an arrester be replaced after it has safely vented pressure?

Immediately, if it can no longer protect against venting

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Surge arresters rated less than 1Kv must not have grounding conductor smaller than 14 AWG copper or aluminum.

False

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is an energized work permit always necessary?

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Insulating rubber gloves can be cleaned with chemicals?

False

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Higher surge arrester ratings are proffered because they have the highest margin of protection for the equipment.

False.

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Highest voltage of a nickel based battery

1.2v

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Testing of CT’s should verify they cannot be

open circuited

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What is anti-pump?

The circuit breaker can only be closed once for an operation of the control switch to the close position.

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What insulating material is best rated for dielectric loses.

PE(polyethylene)

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What power provides lighting and protection power in power failure.

emergency

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rooms with exposed electoral parts are forbidden to all except _________ persons.

qualified

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Benefit to transformer core grounding strap?

single point ground

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limited approach boundry

unqualified person and anything conductive must be out of this area.

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What gas does NOT indicate overheating of a transformer

methane

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lead acid battery each cell can have mow many volts

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What do motor starter blow out coils do

create magnetic filed the draws the arc into the chute

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minimum clearance between 600v normally open conductors need to be _____ apart according to NEC.

12"

study electrical theory

seriously do it

isolation transformer all windings will have the same volts per turn?

Yes

Relays in protection scheme are for

sensing

what circuit is not in a typical distribution system?

secondary loop

electrical system where each transformer can be supplied from either of 2 sources is called a

primary selective system.

What test should not proceed with until busway IR levels are above minimum?

Dielectric withstand (Hipot)

training for NFPA 70E is in class or the field?

Either

What measures the charge of a lead acid batery

hydrometer

one test that is NOT required for silicone insulation liquid

interfacial tension.

restricted approach boundary of 69Kv system

3'6"

most common control wiring insulation class

600V.

what insulating liquid has the highest fire point

Silicone

One coulomb per second describes what?

Ampere

What type of diagram is best for troubleshooting?

Schematic

importance of CT''s

reduces supplied AC for relay applications

a multimode fiber cable spliced with a single node cord will lose power due to diameter difference?

True

A wye-delta transformer has a primary line voltage of 7200 V and a secondary line voltage of 480 V. What is the turns ratio?

8.66:1 (use 7200/1.73 for the calculation. that gets you 4160/480 since the wye winding is included.)

Losses in the core of iron core inductors include _____ and _____ losses.

eddy current, hysteresis

What is the expected torque (pound-feet) value of a 3/8" Grade 5 bolt?

What should be done if rubber insulating gloves are contaminated with oil based compounds?

Discard and replace them

The invention of the ____ made long distance transmission lines practical.

transformer

Overcharging of a lead acid battery can produce which gas?

Hydrogen

Calculate the amplitude of a waveform having a peak output of 100V at an angle of 45 degrees. Vi = Vp*SIN(Angle)

70.71 V

Schematic diagrams should always be drawn with switches and contacts shown in a de-energized position.

True

What does the "Operating Duty Cycle" indicate for a circuit breaker?

The sequence of operations in a specific period and interval.

Which of the following refers to the current a switchboard or protective device can carry continuously without deterioration and without exceeding temperature rise limits?

ampere rating

In an AC circuit, if frequency is increased which of the following is true:

Inductive Reactance increases Help: XL = (2πfL) XC = 1 / (2πfC)

In what format are schedules typically expressed in electrical distribution drawings?

Tabular form

When protecting dry-type transformers greater than 1000kVA from voltage spikes, a _____ type arrester is commonly used.

intermediate class

At what IR value does a P.I. test become ambiguous? Your Answer: 10 Gigohm

5 Gigohm

Choose the best answer that defines: "An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure."

AHJ (Authority Having Jurisdiction)

When a device equipped with ZSI senses a short circuit or ground fault, it sends a restraint signal to the ZSI device just ______ from it. This activates the preset time delay on the _____ device.

upstream, upstream

Piezoelectricity is caused by _______.

pressure

Inductors resist sudden changes in ____ .

Current

In motors, which of the following relay protection is provided as protection for unbalance in the loading of the machine:

thermal protection

What is the term often used to refer to a concrete-encased electrode?

Ufer ground

In most instances, the arc flash boundary is the __________ of all approach boundaries to the electrical hazard.

outermost

When may circuit breakers be installed in parallel for a single load?

Only when factory assembled

Does the Wheatstone bridge system require an electrical power source?

Yes

According to NFPA 70E, all employees shall be instructed to be alert at all times when they are working within the limited approach boundary of energized electrical conductors, regardless of the operating voltage.

False

What is the calculated MVA rating for a 15kV Vacuum circuit breaker operating at 13.8kV with an interrupting rating of 1600A and a short circuit rating of 25kA?

650 Help: MVA = SC x (Max Voltage x 1.732) / 1,000,000

A watt-hour meter has a watt-hour constant, Kh, of 1.2 it is used with 1200/5 ratio current transformers and 14,400/120 potential transformers. What is the primary watt-hour constant Kh?

34,560

Which factor(s) determine the best thermal imaging camera for an inspection?

The type of equipment and environmental conditions

What is the maximum acceptable leakage current for electrical shock resistant (EH) footwear under dry conditions?

3.0 milliamperes

Why is it essential to have a good understanding of the basic operating principles of each piece of equipment when performing infrared scans?

To recognize abnormal heating patterns specific to individual components

Insulated hand tools are dielectrically tested at ______.

10,000 VAC

When evaluating insulation test results on a medium-voltage, air-magnetic circuit breaker, what quantity is evaluated?

Watts-loss

Two capacitors, a 20 µF and a 30 µF, are connected in parallel to a 400 Hz source. The total capacitive reactance is

7.96 ohms

Electrical system grounding will stabilize the voltage to earth during normal operation.

True

The 50 element will:

Cause a circuit breaker to trip with no intentional delay when current exceeds the pickup level.

An emergency system shall have adequate capacity and rating for ______ to be operated simultaneously.

all loads

Which parameter provides insight into the intensity of the electrical discharges occurring within a cable's insulation during PD (Partial Discharge) testing?

PD Level

Which option does NFPA 70B define as “a managed program of inspecting, testing, monitoring, analyzing, and servicing electrical systems and equipment with the purpose of maintaining safe operations and production by reducing or eliminating system interruptions and equipment failures?”

Electrical maintenance program