Final Practice Flashcards by Matthew Steele

Proper ground conductors must be of a sufficient gauge to carry any _______, which may be imposed upon it.________

current, currents

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Grounding protects automation systems from what four(4) potential damages?

A)operator system error

B) voltage fluctuations

C) loss of voltage

D) surges

E) short circuits

F) lighting

G) Power system harmonics

B) voltage fluctuations

D) surges

E) short circuits

F) lighting

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Braided outer conductors or metal foil wrapped around 2 conductors in a signal line are called

(shields, shielding)

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Instrumentation wires come in twisted pairs. One wire is black and the other is White. For DC electrical circuits, the following colour-coding designation is used for Polarity. (the majority of time!)

Match

White wires

Green wires

Black wires

are designated to have positive polarity in DC circuits
designated to have negative polarity in DC circuits
are designated to be connected to ground in DC circuits (no polarity).

White wires are designated to have positive polarity in DC circuits

Green wires are designated to be connected to ground in DC circuits (no polarity).

Black wires designated to have negative polarity in DC circuits

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The function of any grounding system is, therefore, to bring the voltages on all circuits within a system to the same reference or common point

A) True
 	B) False

A) True

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Multi-strand wires are the most common type of conductor in use in industry today.

A) True
 	B) False

A) True

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A Megger device is basically a small high voltage generator.

The Megger generates relatively high voltages in amounts of 1000V

A) True
 	B) False

A) True

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In general, effective grounding means:
A) The path to ground is continuous & permanent

B) be of sufficient capacity and made of aluminum

C) Any and all terminals on the ground system must be corrosion-free and tight, to avoid resistance at the terminal junctions

D) Terminated in a control room or enclosed wire way

A) The path to ground is continuous & permanent

C) Any and all terminals on the ground system must be corrosion-free and tight, to avoid resistance at the terminal junctions

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The two types of coupling that exist are________and ________

(inductive, capacitive)

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Usually the frame of an electrical device is a reference point, where all the circuits of the device eventually connect together

Chassis Ground (Common)

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Is simply a point in a series of circuits where a common reference can be found.

System Common

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common reference point where all circuits will lead to an earth-body connection.

Earth Ground

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Usually caused by the double grounding of the neutral conductor in a system.

Ground Loops

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Is a conductor, provided to ensure electrical continuity in any metallic non-current-carrying parts of electrical equipment

Bonding Conductor

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Used to keep non-current carrying equipment equi-potential to each other

Bonding Jumper

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noise introduced into circuits through conductors, and caused by switching transients

Conducted Noise

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noise produced by communication radios, etc.

Radiated (Plane Wave) Noise

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noice introduced into a system via electromagnetic field induction (capacitive or inductive).

Coupled Noise

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Improper grounding of intrinsically safe barriers in IS applications. Depending on the application and model, some of these units shouldn’t be grounded!

    A) True
 	B) False

A) True

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Instrumentation cabling and equipment is shielded to prevent accidental shock to personal.

A) True

B) False

B) False

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Which of the following statements is true for a delta-connected three-phase system?
A) Phase voltage is higher than line voltage by a factor of 1.732
B) Line voltage is less than phase voltage by a factor of 1.732
C) Line voltage and phase voltage are the same
D) Line voltage is higher than phase voltage by a factor of 1.732

C) Line voltage and phase voltage are the same

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A three-phase load has a phase voltage of 240V and a phase current of 18A. What is the apparent power of this load?

A) 22,449VA
B) 12,960 VA
C) 4320 VA
D) 7483 VA

B) 12,960 VA

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An alternator with a line voltage of 2400V supplies a delta-connected load.The line current supplied to the load is 40A. Assuming the load is a balanced three-phase load, what is the impedance of each phase?

A) 26.4 ohms
B) 103.9 ohms
C) 34.7 ohms
D) 60 ohms

B) 103.9 ohms

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Which of the following statements is true for a wye-connected three-phase system?

A) Line voltage is higher than phase voltage by a factor of 1.732
B) Phase voltage is higher than line voltage by a factor of 1.732
C) Line voltage and phase voltage are the same
D) Line voltage is less than phase voltage by a factor of 1.732

A) Line voltage is higher than phase voltage by a factor of 1.732

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A delta-connected alternator is connected to a wye-connected resistive load. The alternator produces a line voltage of 240V and the resistors have a value of 6 ohms each. Find * True Power * Line current to the load * phase voltage of the load

138. 6V 23. 1 A 9600 watts

A three-phase wye-connected load is connected to a 480V three-phase line. The line current to the load is 36A. If this load is pure resistive, what is total amount of power being used in this circuit?

29,929 watts

How many degrees out of phase are the voltages of a three-phase system?

120 deg

Which of the following statements is true for a delta-connected three-phase system? A) Phase current is higher than line current by a factor of 1.732 B) Line current is higher than phase current by a factor of 1.732 C) Line current and phase current are the same D) Line current is less than phase current by a factor of 1.732

B) Line current is higher than phase current by a factor of 1.732

A delta-connected three-phase load is connected to a 560V line. The loads have an impedance of 14 ohms per phase. What is the apparent power of this connection?

67,200 VA

A delta connection has 30A of current flowing through each phase winding. How much current is flowing through each of the lines supplying power to the load?

52A

The windings of a three-phase alternator are connected delta. The alternator is producing a line-to-line voltage of 480V. What is the voltage across the phase windings?

480 V

An alternator with a line voltage of 2400V supplies a delta-connected load. The line current supplied to the load is 40A. Assuming the load is a balanced three-phase load, what is the impedance of each phase?

103.9 ohms

A wye-connected load has voltage of 600V applied to it. What is the voltage applied across each phase?

347V

A three-phase alternator supplies power to a delta-connected resistive load. The alternator has a line voltage of 480V and each resistor of the delta load has 8 ohms of resistance. Find: I phase of load I line E phase

I Line (load) = 103.92A E phase (load) = 480V I Phase (load) = 60A

A hazardous location is classified as a Zone 2 if flammable vapors are present less than _____ hrs per year.

Intrincisally Safe ( IS) wiring and grounding must comply with the following: A) use only one ground B) wiring must be placed in a separte panel C) be separate from power and other cables D) R of ground > 1 ohm E) colored light blue F) Ground wire must be at least 12 AWG and insulated except at the connection point

B) wiring must be placed in a separte panel C) be separate from power and other cables E) colored light blue F) Ground wire must be at least 12 AWG and insulated except at the connection point

Seals are required when conduit crosses and area classification boundary. A) True B) False

A) True

The two factors which define the explosive properties of a particular gas in CEC groups are: A) pressure and temperature B) degree of corrosiveness and water content C) temperature and volume displaced D) pressure and explosive wave propagation rate

A) pressure and temperature

``` What is the Act called that is a comprehensive legistlative framework for public safety in the Province of Alberta? A) The Building Code B) The Regulations Act C) The Provincial Fire Code D) The Safety Codes Act ```

D) The Safety Codes Act

Protection by design and unable to ignite combutible materials, under normal or fault conditons is called

Intrinsically Safe

Conduit and cable seals are designed to operate under process pressure conditions. A) True B) False

B) False

An Explosion Proof enclosure means: A) Enclosure designed to trap gas or vapors and allow them to be safely vented to atmosphere. B) Enclosure that prevents an internal explosion from occuring in the first place. C) Enclosure designed to withstand an internal explosion withour rupture D) Enclosure that, if opened, will allow gas or vapors to escape

C) Enclosure designed to withstand an internal explosion withour rupture

``` A calibration performed on an active system is called a(n): A) bench calibration B) in situ bench calibration C) lab traceable calibration D) in situ field calibration ```

D) in situ field calibration

What one safety issue should be highlighted when performing field calibrations on electrical equipment? A) mistaking a high voltage area for a low voltage area during calibration. B) ensure you are calibrating the correct instrument C) performing a calibration when the process is not completely de-energized. D) performing the calibation when not required to do so.

A) mistaking a high voltage area for a low voltage area during calibration.

Threaded joints on covers and conduit entries in an Explosion Proof enclosure, is considered: A) a tortuous path to reduce the energy of gas when flowing into an enclosure B) a path of no gas flow at all. C) an easy path to vent gases D) a strong mechanical joint to ensure that the enclosure remains immovable

A) a tortuous path to reduce the energy of gas when flowing into an enclosure

The main component used in a barrier protected in an IS system is the fuse. A) True B) False

B) False

All electrical equipment used in hazardous locations must consist of a certification mark. A) True B) False

A) True

Symbols for 1. Intrinsically Safe 3. Increased Safety 4. Oil Immersed 5. Pressurized 6. Powder filled 7. Encapsulation 8. Non-Incendive 9. Special Protection

Symbols for 1. Intrinsically Safe i ia ib 2. Flame Proof d 3. Increased Safety e 4. Oil Immersed o 5. Pressurized p 6. Powder filled q 7. Encapsulation m 8. Non-Incendive n 9. Special Protection s

"p" protection is where a purge or pressurization is applied to an enclosure to prevent explosive gases from entering the enclosure. A) True B) False

A) True

Class II, Division I are areas described as follows: A) an area where there is a hazardous area containing combustible fibers in active manufacturing B) an area where there is a hazardous area containing combustible dusts under normal operating conditions C) an area where there is a hazardous area containing combustible dusts under abnormal operating conditions D) an area where there is a hazardous area containing combustible fibers in storage.

B) an area where there is a hazardous area containing combustible dusts under normal operating conditions

Class 1 further divides into three zones; which are determined by: A) frequency and duration of exposure to explosive gas B) whether or not the area is ventilated C) area and location of a particular part of a plant D) the type of group that is present

A) frequency and duration of exposure to explosive gas B) whether or not the area is ventilated C) area and location of a particular part of a plant

As an instrumentation technician/technologist you are allowed to install power wiring. A) True B) False

B) False

A grain elevator would be classed as a: ``` A) class 2 enviroment B) class 1 enviroment C) class 3 enviroment D) non-hazrdous enviroment ```

A) class 2 enviroment

Install only essential electrical equipment in hazardous areas. A) True B) False

A) True

Equipment that under normal operation is incapable of igniting gases or vapors are called: A) Positive Ventilation B) Explosion Prrof C) Non-Incendive D) Instrincially Safe

C) Non-Incendive

``` If the concentration range for methane is 5% to 17 % by volume, then 5% by volume of methane is considered to be: A) 100% UEL B) 0% UEL C) 100% LEL D) 0% LEL ```

C) 100% LEL

A Class I location is identified as Zone 1 if flammable gasses or vapors occur in normal operation. A) True B) False

A) True

Gas groups are divided into 2 main areas: A) mining and surface industries B) Acetylene and all other gases C) A and B D) Class I and Class II

A) mining and surface industries

The CEC applies to all jurisdictions in Canada. A) True B) False

A) True

In Canada, all new installations must conform to the new Zone system A) True B) False

A) True

If your facility is classified under the old Division system, then you can continue using that system, even when adding new additions to the installation. A) True B) False

A) True

As an Instrumentaiton Technician/technologist, you are allowed to install and terminate electrical connections to measurment and control equipment. A) True B) False

A) True

``` Identify the hazardous class for the following materials: rayon fibers grain dust gasoline wood shavings cotton aluminum dust flammable paint and solvents acetylene ```

``` rayon fibers 3 grain dust 2 gasoline 1 wood shavings 3 cotton 3 aluminum dust 2 flammable paint and solvents 1 acetylene 1 ```

Select the following statements that describe Explosion Proof equipment. A) Protect covers from damage when off. B) Five thread engagments on covers C) Keep threads and flat surfaces clean D) De-energize circuits before removing covers E) Use lugs to tighten covers. F) All threads must be lubricated

A) Protect covers from damage when off. C) Keep threads and flat surfaces clean D) De-energize circuits before removing covers

A Safety Codes officer requires a warrant to enter a jobsite in order to carry out an inspeciton for the purpose of ensuring the Act is being complied with. A) True B) False

B) False

``` Which zone has the highest hazard level? A) Divison 1, Zone 0 B) Divison 2, Zone 0 C) Division 1, Zone 2 D) Division 1, Zone 1 ```

A) Divison 1, Zone 0

``` Class 1 are hazardous because of: A) coal dust B) gases and vapors C) flyings and metal particles D) grain dusts and powders ```

B) gases and vapors

The aim of pressurization is change the area classification from Zone 1 to Zone 2 or Zone 2 to Non-Hazardous.. A) True B) False

A) True

A synchronous motor is an induction motor A) True B) False

B) False

The ________in a D.C. generator, changes the AC produced in the armature into D.C.

COMMUTATOR

``` What type of motor was the first to be invented? A) single phase A.C. motor B) D.C. generator C) D.C. motor D) A.C. generator ```

C) D.C. motor

Alternators operate on the same principle of electromagnetic inductions as D.C. generators, but they A) don't require a magnetic field needed to achieve an output voltage B) have armature conductors rotate outside the magnetic field C) have no commutator to change the AC produced in the armature into D.C D) have no Rotor that actually spins

C) have no commutator to change the AC produced in the armature into D.C

A voltage induced in the armature windings that opposes the applied voltage in known as ________)electro-motive force

COUNTER

``` The entire North American continent is powered by A.C. generators connected A) individually in series B) individually in parallel C) together in series D) together in parallel ```

D) together in parallel

The principle of operation of all three-phase motors is a Rotating magnetic field! A) True B) False

A) True

The function of the commutator in a D.C. motor is to act as a ________switch to keep the current flowing in the proper direction through the armature.

ROTARY

Most of the electric power in the world today is produced by A.C. Generators or ________

Alternators

The three basic types of three-phase motors: 1st is the Squirrel-________motor. Then the ________-rotor motor. And finally the one that runs at constant speed is referred to as the ________

cage Wound synchronous

The position at which there is no induced voltage in the armature of a D.C. generator is called the Neutral ________

Plane

What two (2) factors determine the amount of Torque developed by a D.C. motor? A) type of commutator used in the machine B) What the Pole pieces are made of C) The strength of the magnetic field of the armature D) The strength of the magnetic field of the pole pieces

C) The strength of the magnetic field of the armature | D) The strength of the magnetic field of the pole pieces

The principle of operation of a D.C. motor is Attraction and ______of magnetism.

repulsion

The ______are used to make contact with the commutator[IN A D.C. MACHINE] and to carry the output current to the outside circuit.

brushes

``` The Armature marking on a D.C. generator are labeled A) F1 & F2 B) no markings C) A1 & A2 D) S1 & S2 ```

C) A1 & A2

The three factors that cause the magnetic field to rotate are: 1. The three voltages are 120 degrees out of phase 2. The arrangement of the stator windings 3. The voltages ______polarity at regular intervals.

reverse

What is a "synchronous speed"? A) The speed of the rotation rotor B) speed of cutting action of rotor C) the speed on the nameplate of a motor. D) The speed of the rotating magnetic field

D) The speed of the rotating magnetic field

The output voltage of a 3 phase alternator is controlled by the amount of D.C. ______current.

excitation

A rotating armature always produces A.C. voltage A) True B) False

A) True

The TORQUE produced by an induction motor is based on 3 attributes: 1. The strength of magnetic field of the rotor 2. The strength of magnetic field of the stator 3. The ______difference between rotor and stator flux.

phase angle

``` What frequency should be applied to a six-pole motor to produce a synchronous speed of 400 RPM? A) 80 Hz B) 20 Hz C) 40 Hz D) 60 Hz ```

B) 20 Hz f = [6 x 400Hz]/120

Calculate the number of turns needed in the secondary winding of a transformer to transform a primary voltage of 300 volts down to a secondary voltage of 180 volts, if the primary winding has 1150 turns of wire.

690 t

What are common efficiencies of transformers?

90 to 99 %

Laminated cores are preferred because ________

A) lamination acts as an insulator to reduce eddy currents

When you use a Step-down transformer the current on the primary side will always be ____________ the secondary current!

Less then

The most common type of control transformer uses what configuration?

two primary and one secondary winding

What is an Auto-transformer?

A transformer that has only one winding for both primary and secondary

Center-tapped Transformers have what is referred to as a Neutral conductor. This conductor will carry the

Sum of the unbalanced load

The ability of one coil to induce a voltage into another coil is referred to as______

mutual induction

Final Practice Flashcards

(97 cards)