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LINEMAN APPRENTICE LINEMAN GENERAL
KNOWLEDGE EXAM QUESTIONS AND 100%
VERIFIED ANSWERS
Questions for Apprentice Lineman preparing for Journeyman's exam. What year was the IBEW formed, and who was its President? - ANSWER 1890, Henry Miller What should be checked for when examining as injured person? - ANSWER 1. Breathing
- Pulse
- Head Injury
- Paralysis on one side of the face
- Laryngectomee
- Stains and burns on or around the mouth What is shock? - ANSWER A depressed state of all body functions due to failure of the circulatory system. What are some signs of shock? - ANSWER 1. Increased shallow breathing
- Cold clammy skin
- Low body temperature How should shock be treated? - ANSWER 1. Maintain normal body temperature
- Ensure adequate oxygen supply
- Keep warm
- Control bleeding if necessary lie down with your head lower than feet
- Do not move unless necessary What are ways to control bleeding? - ANSWER Direct pressure on the pressure point and in extreme cases tourniquet. What is artificial respiration? - ANSWER The forcing of air into the lungs of one who cannot breathe for himself. How deep should a gain be cut? - ANSWER 1/2" Poles set on curves, corners, and strain points should be set __________ inches deeper. - ANSWER 6 If a pole is set near an energized line what precautions should be taken? - ANSWER 1. Cover with protective equipment
- Feeder holds
- Rubber gloves Wood poles are classified by their: - ANSWER 1. Height
- Top circumference
- Circumference 6' from the bottom of the pole The denominator of an improper fraction is __________ than the numerator. - ANSWER smaller What materials do electrons travel freely through? - ANSWER conductors If few electrons travel freely through a material, that material is said to be an _________. - ANSWER insulator Is there such a thing as a perfect insulator? - ANSWER no The opposition to current flow through a material is called? - ANSWER resistance What is the unit of measurement of resistance? - ANSWER Ohm What is the resistance of 1000 feet of #10 copper? - ANSWER 1 Ohm What is electric current? - ANSWER The definite drift of electrons from a point of negative potential to a point of positive potential. The unit of measurement of electromotive force is the: - ANSWER Volt The unit of current flow is: - ANSWER Ampere In a circuit the current is __________ proportional to the voltage and __________ proportional to the resistance. - ANSWER directly, inversely The __________ at which work is done is power. The formula for this is: - ANSWER rate, Power = Work ÷ Time One joule of work done in one second of time is one __________ of electrical work. - ANSWER Watt The unit of electrical work is the __________? - ANSWER Joule The unit of electrical power is the __________? - ANSWER Watt
What is the formula for resistance in a parallel circuit? - ANSWER 1/Rt = 1/R₁ + 1/R₂ + 1/R₃ + 1/R₄... What is the formula for total current in a parallel circuit? - ANSWER It = I₁ + I₂ + I₃ + I₄... What is the formula to find total power in a parallel circuit? - ANSWER Pt = P₁ + P₂ + P₃ + P₄... What is produced when a conductor is moved through magnetic lines of force? - ANSWER an EMF is induced A device used to convert AC power from one combination of voltage and current to another is called a __________? - ANSWER transformer The sheet iron core of a transformer forms a closed: - ANSWER magnetic circuit How are the primary and secondary windings of a transformer coupled? - ANSWER magnetically What is the formula for number of windings to voltage? - ANSWER voltage primary/voltage secondary = number of turns primary/number of turns secondary What destroys transformers in an overload situation? - ANSWER heat The purpose of oil in a transformer is: - ANSWER cool and insulate the coils What keeps a transformer from acting as a short circuit? - ANSWER Counter voltage (aka: back voltage, CEMF) What is usually the maximum temperature the insulation in a transformer can stand? - ANSWER 221° F (105° C) Why are underground transformers and their bushings hermetically sealed? - ANSWER To guard against moisture damage. What does a CSP transformer have that a conventional does not? - ANSWER 1. Primary lightning arrestor
- Primary protective fuse link
- Overcurrent protection on secondary
- Overload Signal lamp
- External Operating handle for opening and closing secondary
- No load tap changer What is the formula for resistivity of a wire? - ANSWER R = (K x L) ÷ A
Where: R = resistance K = specific resistance L = length of wire in feet A = circular mil area What are the specific resistance's of copper and aluminum? - ANSWER Copper (Cu) 10. Aluminum (Al) 17.
- 10.4/17 = .6118 ...approx. 60% conductivity of Cu What is specific resistivity? - ANSWER The resistance of a wire one mil in diameter one foot long. A generator with only two slip rings is know as a: - ANSWER A single phase generator (alternating current). A generator equipped with a commutator delivers __________ current. - ANSWER direct What is the equivalent resistance in a magnetic circuit? - ANSWER reluctance What term represents the amount of current multiplied by the specific coil? - ANSWER Ampere-turns Name three methods used to cool transformers? - ANSWER 1. Oil
- Air
- Water How many hertz are used in AC in the United States? - ANSWER 60 Hz What are two types of instrument transformers? - ANSWER Current & Potential Transformers of less that 500 kva are called __________ transformers. - ANSWER distribution
- some texts use 200 kva, others 100 kva Transformers of 500 kva and larger are known as __________ transformers. - ANSWER power
- some texts use 200 kva, others 100 kva How many windings does an auto-transformer have? - ANSWER 1 What ratio does an auto transformer usually have? - ANSWER 2:
__________ percent of the resistance surrounding an electrode is within a radius of 6' to 10' from an electrode. - ANSWER 90 Ground rods should be long enough to reach __________ moisture level of the soil? - ANSWER permanent Codes require that the resistance of a driven ground shall not exceed __________ ohms. - ANSWER 25 Grounds for lightning arrestors should be __________ than 25 ohms. - ANSWER less What are the two types of counterpoise grounding? - ANSWER 1. Continuos (parallel)
- Crowfoot (radial) List two methods to test that the line is dead before installing protective grounds? - ANSWER 1. Rated and calibrated high voltage volt meter
- Fuzzing: not an accepted safe method, you may not see or hear much of anything on lower voltage primary systems, especially on a windy day or at a noisy location. These lower primary voltages can be difficult to read on certain meters even...causing many linemen to bump the phase with the ground before coming on hard with the head/bill of the ground. Just in case a mistake was made, you could pull away easier. What does a good ground require? - ANSWER 1. Low resistance path to ground
- Clean tight connections made at proper points
- Adequate current-carrying capacity of grounding equipment. Where will the primary fuse on a CSP be located? - ANSWER Inside the tank between the primary coil and the primary bushing. The overcurrent protective device on a CSP transformer is located where? - ANSWER On the secondary side inside the tank between the secondary bushing and the secondary coil. Does the red warning light on a CSP transformer mean that an overcurrent exists now? - ANSWER No When the overload circuit breakers are open, the: - ANSWER primary is still energized What is the purpose of line hose? - ANSWER To protect lineman from accidental contact. What is the maximum depth of an excavation without the use of shoring? - ANSWER 4' Material and debris shall not be placed within how many inches of an open trench in which a man can work? - ANSWER 18"
What are the two types of underground cable? - ANSWER 1. Shielded
- Non-shielded Non-shielded cable use is restricted to what voltage? - ANSWER 7200 Aluminum conductors can be damaged by __________. - ANSWER cold flow & galvanic action On a transformer hooked single phase to obtain the higher voltage the secondary must be connected? - ANSWER series To obtain only the lower voltage you must connect the secondary coil in __________? - ANSWER parallel What are the two types of street lighting? - ANSWER 1. Multiple
- Series A change of current in any conductor produces? - ANSWER A change in the magnetic field around it. Can a power line on one side of the road induce a voltage into a telephone circuit on the other side of the road? - ANSWER yes What should be done to prevent a deenergized line from becoming energized by induction? - ANSWER ground the deenergized line The unit of inductance is called __________ and represented by the letter __________. - ANSWER henry, L A change of current in one coil which causes a voltage to be induced into a nearby coil is called __________? - ANSWER mutual induction Mutual inductance of two coils can be increased by decreasing the distance between them? - ANSWER True Can mutual inductance be increased by placing them on an iron core? - ANSWER Yes Which principle does a transformer operate on? - ANSWER mutual induction What is it called when a change of current in a coil induces an EMF in the same coil? - ANSWER self induction
Stockbridge damper is designed to prevent what? - ANSWER Resonant Vibration When a wye secondary is used on any bank what should be done with the neutral? - ANSWER solidly grounded Remember: "Wye - Wye you tie" "Wye - Delta you float" (CLOSED BANK ONLY for normal operation...However, use a stinger/teaser/fourth cutout for switching purposes. You must treat that insulated floating neutral as energized primary until it is tied dowm. ...ALL open bank combinations have neutral permanently tied down Bending hot sticks should be kept to a __________? - ANSWER minimum The current in a transformer winding when connected delta is: - ANSWER line current ÷
How does winding voltage compare with line voltage when transformers are connected delta?
- ANSWER winding voltage = line voltage The voltage across transformer windings when connected wye is: - ANSWER winding voltage = line voltage ÷ 1. How does winding current compare with line current when transformers are connected wye?
- ANSWER line current = winding current To convert an underground cable to an overhead line requires _________ and a __________.
- ANSWER riser, pothead If an underground riser is low voltage it terminates in a __________ __________. - ANSWER weather head If the termination is high voltage it terminates in a _________. - ANSWER pothead Name two types of potheads? - ANSWER 1. one conductor
- three conductor How is a pothead attached to the sheath of the cable? - ANSWER wiped joint or a clamping joint What is the purpose of a pothead? - ANSWER To separate conductors and to seal out water.
What is another name for galvanic action? - ANSWER electrolysis What determines how the secondary of a bank is hooked up? - ANSWER customer demands What are the formulas for finding the capacity of an open bank? - ANSWER 57.7% of total closed bank, or 86.6% of remaining cans What should be hooked up first when installing a transformer on transformer bank? - ANSWER grounds and then neutrals What are the three ways to sag a conductor? - ANSWER 1. Dynamometer
- Timing mechanical waves with a unisagwatch
- Transit What are the four principle types of electric discharge lamps? - ANSWER 1. Sodium
- Mercury vapor
- Halide
- Florescent How does an incandescent lamp work? - ANSWER A wire filament sealed in a glass tube with the air pumped out is heated by a electric current that causes it to glow, it must be heated to 5000°F What are lamps rated output in? - ANSWER lumens The highest value that a demand reaches is called the __________ __________. - ANSWER Peak (max.) demand What determines the size and type of equipment necessary to supply the consumer? - ANSWER Max. demand What is the formula to determine load factor? - ANSWER Load Factor = Average Demand ÷ Maximum Demand How much can a booster transformer boost line voltage? - ANSWER 5% or 10% How should the secondary coils be connected to boost the voltage 5%? - ANSWER parallel How should the secondary coils be connected to boost the voltage 10%? - ANSWER series A booster transformer is connected with the primary in __________ with the line, and the secondary in __________ with the line. - ANSWER parallel, series
Why does inductance have a greater effect on AC circuits than it does on a DC circuit? - ANSWER The fields are always changing, causing a break in flux lines. Define electro-magnetic induction. - ANSWER The process of inducing a voltage in a conductor by the action of a magnetic field. What is inductance? - ANSWER The ability of a magnetic field to induce a voltage in a conductor. Measured in Henry's Define capacitance (C). - ANSWER The ability of a circuit or component to store an electric charge. Measured in farads. or The ratio of the electric charge transferred from one to the other of a pair of conductors to the resulting potential difference between them. Define capacitive reactance (Xc). - ANSWER The opposition to the flow of current in an AC circuit due to capacitance (caused by a capacitor). Measured in Ohms. Xc = 1 ÷ (2 x 3.14 x ƒ x C) Where: Xc = capacitive reactance ƒ = frequency of the applied voltage measured in hertz C = capacitance in farads Define impedance (Z). - ANSWER The total opposition to the flow of current in an AC circuit. or The vector sum of the oppositions found in some AC circuits. The vectors may include inductive reactance, capacitive reactance, and resistance. The vector addition of these components results in the total opposition to the AC current flow. Measured in Ohms. What is power factor? - ANSWER The ratio of true power in watts to apparent power in volt-amps. or A factor applied to the apparent power to yield a true power. The power factor decimal is expressed as a percentage. It is also the ratio of watts divided by volt-amperes expressed as a percentage of true watts compared to apparent volt-amperes.
When a circuit has a large portion of its impedance made up of inductive reactance it will have a __________ power factor and a __________ current. - ANSWER low, lagging When a circuit is made up of a resistance alone it will have a _________ power factor and the current will be _________ __________. - ANSWER high, in phase What is it called when an AC circuit induces a EMF in a nearby circuit? - ANSWER mutual induction The presence of capacitance in a circuit tends to resist changes in _________. - ANSWER voltage What is a capacitor, or a condenser? - ANSWER Items manufactured to add capacitance to a circuit. What are the three factors that affect the capacity of a capacitor? - ANSWER 1. Surface area of internal plates
- Distance between the plates
- Insulating material How are capacitors rated? - ANSWER KVAR (Kilo Volt Amperes Reactive) What should you do after taking a capacitor out of service? - ANSWER Wait five minutes, short (shunt) out the bushings and ground. What are capacitors used for? - ANSWER To improve power factor and voltage, and to supply leading current. What causes reactive power? - ANSWER Any device that has an iron core and a coil. In which transformer component does the magnetic field oscillate? - ANSWER iron core What is permeability? - ANSWER The ease at which an iron core conducts lines of force. or The degree to which a material focuses magnetic lines of flux, or the ease with which magnetic lines of force distribute themselves through a material. Permeability is a factor compared to air (permeability of 1). There is no unit of measure, just a factor compared to air. The symbol used for magnetic permeability in a formula is the lower case Greek letter mu (μ). Which winding is the tap changer in? - ANSWER primary
- Test line (First, set the tester to the correct setting for the voltage to be measured. Second, test the tester on a known energized source. Third, test denergized line for voltage presence. Finally, re-test tester on known energized line)
- Ground line to prove deenergized. (attaching neutral first then phases using approved live line tool, working your way in/grounding nearest phase first...remove in reverse order) What are the requirements of a good ground? - ANSWER Low resistance path to earth, clean connection, tight connection, connections made at proper point, adequate current carrying capacity of grounding equipment. What are capacitors equipped with that allows it to be discharged in five minutes? - ANSWER Internal discharge reistor Which winding in a step regulator is regulated? - ANSWER secondary In a step regulator the primary winding is connected ________ the line while the secondary winding is connected in _________ with the line. - ANSWER parallel, series What is the range that a step regulator regulates? - ANSWER 10% below to 10% above The tap changer switch in a regulator is __________ driven and immersed in __________. - ANSWER motor, oil What are the two different types of regulators? - ANSWER 1. Induction
- Step Step regulators usually provide __________ steps at __________ each. - ANSWER 32, 5/8% What are the primary bushings of a voltage regulator? - ANSWER S-source L-load SL-neutral Why does an oil switch extinguish arcs better than an air switch? - ANSWER oil is an insulator In an induction regulator which winding is mounted so that it can be rotated on its axis? - ANSWER shunt Which is stationary? - ANSWER series The voltage induced in the series winding depends upon the __________ of the shunt winding. - ANSWER position
What is a transformer usually loaded to? - ANSWER 125% of rating The ratio of current transformers expressed as some value of __________. - ANSWER 5 In general, transformers used for metering installations are called __________ transformers?
- ANSWER instrument The polarity mark of an instrument transformer is normally connected to the __________. - ANSWER line "Dot to the pot" What is the white bushing of an instrument transformer? - ANSWER polarity mark Current transformers are connected in __________ with the line. - ANSWER series Potential transformers are connected in __________ with the line. - ANSWER parallel What must be done to the secondary of a current or potential transformer when it is energized? - ANSWER connected to a load or shorted out What voltages are considered EHV? - ANSWER 345 kV or above When phasing out two circuits, what is the first thing that should be checked? - ANSWER All phases should be checked to make sure sticks are working and the the line is energized. What should be done with the phasing sticks when they are finished with? - ANSWER The should be stored away, they should only be left on the line long enough for the reading to be taken. What must be done to the circuit after phasing out and before tying two circuits together? - ANSWER Regulators must be set in neutral and locked out. What is the purpose of oil in a transformer? - ANSWER insulation and cooling What is normally the maximum safe temperature for transformer insulating material? - ANSWER 105°C (221°F) Any transformer 200 kVA or smaller having primary voltage of less than 8,660 volts has what polarity? - ANSWER additive When looking at an additive transformer, what side is the X1 bushing on? - ANSWER right side
What should be checked for before working in a manhole? - ANSWER gasses and oxygen deficiency atmosphere If circuit voltage is unknown how can it be found out? - ANSWER Check the transformer nameplate and check to see how it is connected or, a Phasing set/High Voltage Voltmeter Why does underground cable rated above 5000 volts require a grounded shield? - ANSWER To prevent eddy and circulating currents. Why transpose transmission lines? - ANSWER To keep the lines in electrical balance and cut down on telephone interference. To maintain 120 degrees of separation between phases. If not transposed it would act more as one phase instead of three after miles and miles of paralleling themselves. What is meant by "getting in series"? - ANSWER Getting a part of your body between the source and ground, or the load. Your body completing the circle/circuit. One horsepower is equal to how many Watts? - ANSWER 746 What is the equation for finding the number of turns in a coil when voltages are known? - ANSWER Voltage (primary) x Turns (secondary) = Voltage (secondary) x Turns (primary) or Full coil primary ÷ Full coil secondary What is the formula for three phase power? - ANSWER ... Demand meters do not normally record surges of 20 minutes or less - ANSWER ... What is the margin for secondary voltage? - ANSWER 10% 120v x 10% = 12 volts so, +/- 6 volts is acceptable (114vv to 126 v)
- KNOW YOUR RUBBER GLOVE CLASSES AND VOLTAGE RATINGS - - ANSWER
- REFERENCE AN OSHA CHART - Class AC Use Acronymic Cuff length system voltage above protector Beige 00 500 Be Red 0 1000 Ready
White 1 7500 With 1" Yellow 2 17000 Your 2" Green 3 26500 Gloves 3" Orange 4 36000 On 4" ...Test voltages are always higher that use voltage ratings Test voltage 00 = 2, 0 = 5000 1 = 10000 Or just remember use voltages are 2 = 20000 always a little lower than test voltage 3 = 30000 4 = 40000 What percentage of a ropes strength does a splice have? - ANSWER 100% What percentage of a ropes strength does a knot have? - ANSWER 40% What is the main purpose of a distribution transformer? - ANSWER To step down the voltage of the primary mains to a usable voltage in the secondary mains. What are the three main parts of a transformer? - ANSWER 1. Core
- Coil
- Can Most distribution transformers have a no load tap changer, what does this mean? - ANSWER It means that the tap changer must be changed only when the can is taken out of service. What is the difference between a Conventional and a CSP transformer? - ANSWER Conventional needs separate cutout and arrestor. CSP has both built in. What dos CSP stand for? - ANSWER Completely Self Protected What is a fuse cutout and its purpose? - ANSWER It is a weak link between the circuit and the electrical apparatus, it protects equipment from short circuit and overload. What is a lightning arrestor and its purpose? - ANSWER It is device connected in series with a resistor that provides a path to ground for a lightning voltage surge to discharge and chokes off the follow-through current. Name four types of arrestors? - ANSWER 1. Spark gap, rod gap
- valve-type
- Metal-oxide varistors (MOV)
