General Flashcards
1
Q
What is a maximeter??
A
A clamp on ammeter having two indicating pointers, one indicates the current at the time of the reading and the other indicates the maximum current since installation
2
Q
Does the load on a capacitor ever change??
A
No, always draws the same amount of current
3
Q
How does a capacitor improve powerfactor and voltage?
A
By providing leading current
4
Q
Why must a gas treated poles be set with extra caution?
A
They can conduct as much as 90% to ground
5
Q
Can a line with out load and still carry current?
A
Yes this is called charging current
6
Q
What are three physical dimensions determine pole classification?
A
Length, circumference 6ft from the bottom of the pole and 2ft from the top
7
Q
Which Carries the most load, the one with the higher impedance or the one lower??
A
The lower,high=more resistant
8
Q
What 2 main parts is osha Made of
A
A.29 cafe (code of federal regulations)
B.1910 for general industry
C.1926 for construction
9
Q
What osha article is a performance standard to address employees who are directly involved with power generation,transmission and distro
A
1910.269 standard
10
Q
What osha (c)overs job breiefings
A
1910.269(c)
11
Q
What osha article covers locke(d)out tag out?
A
1910.269(d)
12
Q
What osha article covers enclosed spac(e)s
A
1910.269(e)
13
Q
What osha article covers PPE?
A
1910.269(g)
14
Q
What osha article covers live line tools?
A
1910.269(j)
15
Q
What osha covers working on (L)ive line parts
A
1910.269(L)
16
Q
What osha article cover minimum approache distance
A
1910.269 (L) (2)
17
Q
What osha article covers grounding for the protectio(n) for the employees
A
1910.269 (n)
18
Q
How many Ibew vice presidential districts are there?
A
11
19
Q
Should poles next to a street crossing face the street?
A
Yes
20
Q
What is meant by ranking a pole?
A
Moving a pole against the direction of the strain
21
Q
Name 3 types of pole roofs
A
Slant,gable,flat
22
Q
Which side of the pole has the longest concave sweep between the ground line and the point of the load
A
Face or belly
23
Q
Gains should be cut in to what side of the pole
A
Face
24
Q
How deep should gains be
A
.5 of and inch
25
An arm that is placed at right angles to a line arm is called a?
Buck arm
26
A class 2 pole is ___ than a class 6 pole
Larger
27
Ground rods should be long enough to reach the ___ moisture level of the soil
Permanent
28
What are two types of counter posie ground?
Continuous(parallel) length of the transmission line
Crawfoot (radial) around the footing
29
What are two methods to test if a line is dead before installing protective ground?
High voltage tester, tic tracer
30
33,000 foot pounds per minute is equal to one
Horse power
31
One horse power is =
746 watts
32
When properly sharpened, the gaff should not have a spike point but it should function as a?
Chisel
33
What is the definition of power
The rate at which work is done
34
Define a guy
A brace or a cable attached to the pole to strengthen it and keep it in position
35
When you visually inspect your rubber gloves what are you looking for??
Correct voltage for the voltage to used on, ozone cutting, mechanical damage, discoloration
36
Which winding of a constant current transformer is moveable
Secondary
37
What must be done to the secondary side of a current transformer before heating up the primary side
Shorted,shunted,or hooked up
38
If you don’t short or shunt or hook up the secondary side of a CT what happens
High circulating current will appear
39
The polarity mark of an instrument transformer is normally connected to what side?
Load side
40
In general what are transformers used for metering installation called
Instrument transformer
41
What is the white bushing of an instrument transformer
Polarity mark
42
Typical rule for capacitor replacement
2/3 of the distance where the voltage has dropped 2/3
43
How are distribution and substation capacitors connected?!
A.distro-parallel
B.sub- series
44
Two types of capacitors
Switched and fixed
45
Volts=
Amount of potential that will cause 1 coulomb to do 1 joule of work
46
Three types of hydraulic reclosers and ratings
H-type operates 5-50amps
L-type operates 35-280
D type are voltage specific
47
Which rope is considered an insulator
Clean dry polypropylene rope
48
Two types of xfmr construction
Core type and shell type shell is the most common
49
How should a one bushing capacitor be treated??
It should be treated like a one bushing xfmr, due to improper grounding case could be come hot
50
Can a 6kva capacitor bank consists of a 6-100 ckva capacitors
Yes
51
What is a megger
A device used for testing high voltage resistance
52
Air arrestor=
Air gap in series with a resistor
53
What are the three methods of cooling a transformer
Oil,air,water
54
What are constant current xfmr a usually fixed at?
6.6 amps
55
What is an OTDR,
optical time delay reflectometer, used to test fiber
56
Three major components of an implosion sleeve
Steel inner,inner aluminum outter aluminum
57
How many Ibew international executive council’s districts
8
58
How often does the Ibew international convention meet?
5yrs
59
Who was the first Ibew president?
Henry miller
60
When was the Ibew organized?
November 28th 1891
61
Ac sine wave represents one cycle and is ___ -electrical degrees, with max value of ____-degrees and a opposite max value of _____
360,90,270
62
A low power factor due to lagging current condition can be improved by??
Adding capacitors to the line (ELI) inductive circuit needs a capacitance to improve power factor
63
_____,_____ adjust the voltage plus of minus 10% they have _____ boost and ____ buck at____% each step
Step regulators,16,16,5/8%
64
Osha requires a protection system for employees in a excavation 5’ or more. What choices for protection
Benching,sloping, shoring, shielding
65
A conductor with a diameter of 1” would convert to how many kc mills
1000 kc mills
66
Transformer____ratios and transformers_____ ratios are directly proportional
Voltage and turns ratio
67
Closed wye wye or closed delta delta can have one of the two angular displacements
0-180
68
Closed wye delta or closed delta wye can have one of the two angular displacements
30-210
69
An______ is a type of transformer with a single tapped high voltage winding. They are often used in transmission substations for 230kv to 161 kv
An auto transformer
70
Step voltage regulators are a type of auto transformer with primary connected____ with the line and secondary winding connected_____ with the load
Primary connected parallel, secondary connected in series
71
Why is a closed wye closed delta bank primary neutral floated
To prevent back feeding the line when the line becomes de-energized or to prevent back feeding to the high side of the transformer if the fuse blows
72
Why is a fourth cut out installed on a closed wye-delta bank
To prevent ferroresonance-if you do not tie down your neutral while closing the cutout(not having all three potentials) there is a build up of reactance and capacitance of up to 10x the normal voltage until you have all three cutouts closed, by tying down the neutral you will balance the voltage on the bus
73
On a open bank what kva capacity do you have of the two transformers being used
86.6%
74
What must be done before climbing above a de-energized transformer
Isolate the secondary leads
75
What do you need to do on a closed wye-wye xfmr bank
Tie the primary neutral to the secondary neutral to prevent over voltage on the secondary side
76
What purpose does a case ground serve
It grounds the tank and acts as the primary neutral on a single bushing can
77
How do you find full load current on a delta line
Kva/primary voltage times 1.73
78
How do you find full current on a wye line?
Kva/primary voltage
79
Xfmr core; how does it work and what is it made of
The core is part of the transformer in which the magnetic field oscillates. It consists of laminated iron or steel. The insulated coils are wound around the core in a desired shape, there are insulated to help reduce the corse loss and heating produced in the core
80
Describe a xfmr tank
Used to enclose the core and coils, acts as a protective barrier for the high voltage and current carrying parts, and holds the transformer oil
81
What are the xfmr bushings made of
Made of a strong wet process porcelain which insulates the line leads from the tank and are used to bring high voltage and low voltage leads to and from the core
82
There main parts of a csp.
A.circuit breaker on the secondary side
B.external tank mounted lighting arrestor
C.internal high voltage fuse mounted in the primary bushing
83
What are two of the basic types of lighting arrestors
Expulsion and valve
84
What are two main enemies of a transformer
Heat and over voltage
85
Steps to work on a capacitor
A.wait 5 min
B.shunt/short/ground after 5 minutes is over
86
Reclosures
Operates 3-4 times and the 4th time is slower to allow sectionalizer to open or to allow fuse to burn
87
Setctionalixers will not operate under load, they only operate when the reclosures is open
88
Sine wave goes numbers,
0-90-180-270-360
89
Resistance
Opposition to current flow in a conductor
90
What affects resistance
Material,temperature,size of wire
91
Corona
When a conductor is at a potential above the dielectric of air surrounding it
92
Inductive circuit
ELI
Voltage leads amperage or your amperage lags your voltage
93
Capacitive circuit;ICE
Amperage leads voltage or your voltage lags your amperage
94
Step potential
Birdging the gap between the gradient rings
95
Osha glove testing dates
Every 6months
96
Non flammable gas for dissipating an arc
Sf6 gas
97
Protective grounds must be be atleast___ ampacity and be able to handle max fault current
#2
98
Impedance is measured in what
Capacitive reactance, inductive reactance, resistance
99
Air hoses colors
Blue-service
Red-emergency
Green-electric
100
How many years are hot sticks tested
2 yrs
101
How is primary metering measured
CT’s-pt’s
102
What prevents your H1 fed by a phase and H2 being hooked up to ground from going phase to ground
Counter electromagnetic force (emf)
103
What two ratios are the same
Turns ratio and voltage ratio
104
Why do you tie down the neutral on a wye wye
To prevent over voltage and unbalanced loads on your secondary side
105
Resistance is measured in ____
Ohms :R
106
Total opposition to current flow in an ac circuit is called ____ and is measured in ____
Impedance;ohms
107
In an ac circuits with reactance, the voltage can lead or lag current as much as…
90 degrees
108
Can transformers of a different kva be paralleled
Yes if the impedances are nearly the same, the load will split proportionally
109
Define polarity
A designation of the relative direction of current flow in the primary and secondary windings
110
In the box and out of the box
200-8660 transformer rated more than 200 or have higher primary rating than 8669 volts are subtractive
111
In order to properly parallel two transformers what factors what factors need to be checked
Same voltage ratios, nearly the same impedance and the same phase and polarity must be the same
112
The highest tap is called___and the lowest tap is called____
1,I,a
5,v,e
113
The primary booster is a conventional transformer connected how
As an auto xfmr; it is not grounded and has no fuse protection
114
Primary boosters raise and lower voltage by how much
5%-10%
115
What does a ground consist of
An artificial electrical connection to earth. Low resistance
116
In the wye system the voltage from tip to tip represents the?
System voltage
117
In the wye system the voltage from tip to the center represents?
Phase to ground voltage
118
What’s the most popular distribution system
7200/12470
119
How much more efficient is the wye system than the delta System
73%
120
Phasing and rotation rule
Phasing insures rotation, rotation does not ensure phasing
121
What is an unexplainable voltage condition exists in the wye wye and the wye delta transformer connections
Third harmonic 180 hertz unwanted voltage on the system
122
How much larger can the third harmonic voltage be than the phase voltage?
150%
123
On a wye delta connection where will there be a third harmonic voltage measured
Where the neutral bus floats
124
If a customer requests 120/240 three phase four wire, what transformers can be used
120/240
125
If a customer wants 240 three phase three wire what xfmr transformer can be used??
120/240 in series or 240/480 parallel
126
If a customer wants 120/208 three phase four wire what xmfr can be used
120/240 in parallel
127
When going from a closed bank to an open bank what is the kva rating of the bank?
86.6% of the two remaining transformers or 57.7% of the initial 3
128
What is the disadvantage of the open wye open delta bank connection can be a hazard to a lineman working on the bank
The primary neutral also Carries the full load current even though the load is balanced. If the primary neutral connection is disconnected when the bank is energized. One half of the phase to ground will be present
129
Can a csp xfmr’s be used in an open wye open delta bank?
Yes
130
On an open wye open delta bank. What would happen if one of the primary phases were to be switched to the other phase
The rotation would be reversed, all the secondary voltages would stay the same
131
Can a closed delta and an open delta bank be paralleled
Yes when properly phased
132
What condition would exist if one primary fuse blown on an open wye open delta bank or an open delta delta if the three phase load is still connected
A slight back feed voltage will exist on the other primary lead of the blown transformer
133
In a three phase bank how is the single phase and the three phase load split
The lighter pot Carries two thirds of the single phase and each other pot Carrie’s one third of the single phase load, the three phase load splits evenlu
134
What would happen if a csp is used as the lighter pot and the secondary breaker opens
It would isolate the neutral causing unequal voltages and have an open neutral situation
135
When the primary neutral on a wye delta bank is floated and the secondary wild leg is opened to the load the voltage is measured across this gap it will read approximately 1.5times phase to ground
What is this phenomenon called..third harmonic voltage when the primary neutral is grounded the voltage will return to 0
136
In a wye delta bank what two things happen if the neutral bus becomes grounded and a primary xfmr fuse is blown
The bank remains remains the same as before except the bank capacity is reduced to 57% of the banks ratings
137
The transformer on the blown fuse line acts as a step up transformer and provides power to the so called dead line also know as what?
Back feed
138
On a wye delta bank what is the voltage on the floated neutral bus if two transformer fuses are blown
Full phase to ground voltage
139
What is the voltage on a floated neutral bus on a wye delta bank every time it is energized or de-energized or a primary line is ethier energized or de-energized
One half to full phase to ground voltage will be present on the neutral buss
140
Is there third harmonic on a delta delta
No
141
In a wye wye bank what just be done to the primary neutral
It must be tied to the system neutral or else excessive voltage may develop on the secondary side
142
On a wye wye what happens if the primary neutral is disconnected from the system neutral
A third harmonic voltage will exist between the primary neutral and the system neutral and ground. This excessive voltage can be hazardous
143
What is the core of a transformer made of?
Laminated iron or steel core which two or more coils are wound
144
What are 11 components of a transformer
Core,coil,ratio,tank,bushings,cooling,
Losses,taps,impedance,polarity,
Name plate
145
Permeability
The ease at which soft iron conducts magnetic lines of force
146
In coils, in comparison to the primary and secondary coils. What are the size and number of turns and insulation of the coil wires
Primary..more turns, smaller wire,higher insulation
Secondary…less turns, bigger wire,lower insulation
147
What is the shape of the primary and secondary coils
Primary is round or rectangular or sheet
Secondary is usually rectangular or a sheet
148
Askarel is also known as what?
PCB
149
Losses: what are the two main transformer losses
Iron and copper losses which consist of eddy currents and hysteresis losses
150
What does iron loss consist
Eddy currents and hysteresis losses; that’s why the core is laminated
151
The amount of current to fully magnetize the iron core is sometimes known as the
Exciting current or charging current
152
What is the formula for copper loss
I2R
153
When changing taps what happens to the secondary voltage when you raise and lower the taps
1. When you raise it the secondary voltage goes down
2.when you lower it raises the secondary voltage
154
Sysmbol for impedance
Z
155
Capacitance is measured in____and the stability is ___
Farads ;c
156
Inductance is measured in___an the symbol___
Henerys;L
157
Inductive reactance is measured in___and the symbol is___
Ohms;XL
158
Capacitive reactance is measured in ___ and the symbol is___
Ohms;XC
159
Impedance is measured in___and the symbol is___
Ohms;Z
160
A three phase line can use wire___% smaller and hold the same load as 1 phase two wire system
75%
161
Defibrillation can occur from how much to current for how long
1 amp for .01 seconds
162
How often to test grounds
Every 2 yrs
163
How many feet to keep away from lines in a sub
15ft
164
Turns ratio and voltage ratio are
Directly proportional
165
Power factor=
True power divided by apparent power
166
When do you test rubber blankets and sleeves
Every 12months
167
What type of device is a transformer
Electromagnetic device
168
What size of bit do you need for a 5/8’s bolt
11/16 drill bit
169
Why do we put aluminum over copper
Because the copper will corrode on the the aluminum if it is on top
170
Percent efficient of knots,hitches and splices
Knots 50% hitches 75% splices 85%
171
How many lumens are one candle power
12.75
172
Which way does a capacitor improve power factor in line, towards the sub or away
Towards the sub
173
In a capacitor what gives them more capacitance
The size of the plate. The larger the plate the more capacitance, the closer the plates the more capacitance
174
What does a capacitor consist of
Two thin pieces of metal or foil separated by a dielectric, then inserted in to a metal case along with a discharge liquid. At the top one or two high voltage bushings
175
Transformers work off the principle of
Mutual induction
176
What’s does KVAR stand for?
Kilo volt amp reactive
177
What is polarity in a transformer
Direction of current flow between the primary and secondary
178
Power factor equals
True power over apparent power
179
What device breaks the arc on air break switches
The arcing horns
180
What is line loss
The amount of voltage lost by pushing current through a resistance
181
What is the maximum ground resistance a structure can have
25 ohms
182
Heavy load lines are protected by the use
Ocb or ocr sectionalizers and fuse cutouts
183
Sagging charts are used to show what two things
Distance and temp
184
What are two things are checked before final sag is started
Anchors and guys
185
What is buss works in a sub for
Aluminum or Cooper used to connect equipment together
186
What is the force which makes electricity flow
EMF electromotive force
187
If a shock victim received several burns but was not killed, how many amps do you think when through his body
.2 amps
188
Adding parallel loads to a circuit will___ total circuit resistance and___ total circuit current
Decrease resistance and increase current
189
What is the polarity of electrons when they enter a load
Negative to positive
190
How does an analog meter work?
On the principle that like poles repel each other
191
List three steps that should be followed when reading a multimeter
Determine what the meter indicates, determine the full scale value of the meter,read the meter
192
Two types ohm meters
Series and shunt
193
Three factors that determine the amount of voltage that will be induced in a transformer
Number or turns of the wire, strength of the magnetic field,speed of the cutting action
194
Stand taps for a transformer
Normally there is two taps at 2.5% each that go up and two taps at 2.5% each going down with 100% being in the middle
195
Auto transformer are what?
Lower cost,single coil,smaller size,lighter weight,more efficient, less noise then doing a booster
196
What is convection
How oil is circulated in a transformer from hot to cold
197
How over loaded can a transformer before it starts to pop tops
125-150%
198
What kva is a 4 bushing can?
Anything over a 100
199
Y law
Coil amperage=line amperage
Coil voltage x 1.73=line voltage
200
Primary and secondary turns
Smaller wire more turns
Secondary larger wire less turns
201
How are transformer windings connect primary to secondary??
Coils are magnetically coupled
202
Magnetic reluctance
The resistance to the formation of flux in a magnetic circuit
203
Hysteresis losses are
Known as excitation loss, energy consumed when the iron core is magnetized and demagnetized by AC power at 120 time a second
204
Copper loss
The losses in a xfmr due to the resistance of the wires making up the turns of the primary winding
205
How is hysteresis losses reduced
The core is made of more permeable iron making it easier to magnetize and demagnetize
206
What is the core of a transformer made of
Laminated steel or iron of which two or more coils are wound
207
How is a current transformer connected?
Series
208
How is a potential transformer connected
Parallel
209
What is a circular mil
A circle with a diameter of one thousandth of an inch
210
Volts and amps are ____ proportional
Inversely
211
What percentage of electrical contractors worked in the field before hand
83%
212
3 main causes of accidents
Human elements,acts of nature,mechanical failure
213
What is a natural enemy of rubber gloves
Oil and grease
214
What would you use to cover a primary insulator
A rubber blanket or hood
215
Max exposure for rubber goods is
36kv
216
An enclosed space at 5 feet requires what?
Mechanical retrieval device
217
Oxygen levels in an enclosed space must be
23.5 max
20.8 normal
19.5 minimum
218
What is the greatest risk of blood borne pathogens
Hepatitis b
219
Minimum overlap distance of an extension ladder is
3 feet
220
What’s the Safest distance radius from machinery for a swing radius
6ft
221
What is found in pvc that can cause cancer
Carcinogens
222
How many vice presidents districts are in the Ibew
11
223
Oder that union meeting is conducted
Roberts rules of order
224
The light used in fiber
Infrared
225
Extra high voltage is considered what range
34 kv and up
226
In common distro transformers the tap changer is located on what coil
The primary coil
227
What is the main advantage of a wye secondary over a delta secondary
It’s more efficient because the load is balanced
228
Two 50 kva transformer’s are connected open delta open delta. What is the capacitor of the bank
86.6%
229
What are two types of transformers are used for primary metering
Current transformers and potential transformers
230
Transformers are additive polarity if there kva rating is
Less than 200 kva
231
Transformer tap changers are located where
Located in the oil the primary coil and control handle is located above the oil
232
How are lightning arrestors connected
In series with a resistor
233
3 advantages of bundling conductors
Cuts down on corona loss, lower line loss, 50% of the reactance of a single conductor
234
Define corona
An electrical discharge at the surface of a conductor accompanied by the ionization of the surrounding atmosphere
235
When banking transformer what’s a rule of thumb for max safe rating for the bank
Three times the kva of the smallest can
236
What element is the element in apparent power that does not do any work
KVAR
237
1 watt
One amp flowing under one volt pressure
238
How many watts equals one horsepower
746watts
239
Define impedance
Total opposition to the flow of current in an AC circuit, measured in ohms
240
Define inductance
Ability to induce a magnetic field on a conductor
Measured in henrys
241
What type of transformer is used for series street lighting
A constant current transformer
242
3types of faults
Open circuit,short circuit,ground fault
243
Most common reason for transmission line failure
Insulation flashover
244
What is a vector
A line having a magnitude and direction
245
What do you use when raising a conductor to prevent it from falling on the other side
Holding tong
246
What determines the strength of magnetic field when current flows through a conductor
Amount of current
247
T/F an inductive circuit the voltage leads the current by 90 degrees
True ELI the ICE man
248
T/F the external air gap of a distribution surge protectors is designed to prevent spark over by normal system voltage if the lightning arrestor fails
True
249
T/F if lightning arrester connections are to long, to much resistance might force high voltage surges into the xfmr
True
250
T/F in wiring the arrester connections, the wire must be smaller than the primary drop
False
251
What is the safety factor of new rope compared to old rope
New is 5 to one
Old is 10 to one
252
What are three things do you look for in an injured person
Response, bleeding,pulse
253
Can porcelain withstand more compression or tension
Compression
254
What is the main advantage of a pin type insulator
Cheaper and requires shorter pole for the same overhead clearance
255
What is a voltage regulator and how does it work?
An electrical apparatus used to regulate voltage at 10% above or 10% below line voltage at 32 steps alot 5/8 (high side is connected in parallel and the secondary side is connected in series
256
What are the parts of a rope
The fibers, strands, and yarns
257
Formula for RMS
707 x peak
258
RMS is known as
Effective voltage
259
What is a permanent fault
Where the circuit cannot be automatically reckoned. A line crew is needed to repair and re-energize the circuit
260
Formula for line loss
The amount of voltage lost by pushing current through the resistor
I squared R
261
The step voltage regulator is basically a what
Auto transformer
262
What does the load bonus’s settings do on a voltage regulator
Allow the regulator to handle larger amounts of current, used when the voltage regulator becomes over loaded. They are mechanical stop positions
263
Induction regulators have two series coils, by operating the coils in series how will they be rated, how will they be rated in parallel
+-10% when in series, +-5% when in parallel but carry twice the amperage
264
Should surge arrestors be installed on voltage regulators
Yes, on the source side
265
T/F: series can happen when you contact two current carrying sources at the same time
False: second point of contact
266
T/F: if you have high primary voltage on a transformer your secondary voltage will be low
False
267
What is semi con for?
Disperse eddy currents
268
4 ways a transformer is cooled
Air,oil,fans,fins
269
What are the five types of strand conductor shapes
Concentric round,round,compact round, anular,compact sector,segmental
270
How are rubber gloves rated
Phase to phase
271
What type of hard hat do we wear
Type e good for 20,000 volts
272
What are steps are taken for proper ground
Need low resistance
Clean and tight
Connections made at proper points
Adequate current carrying capacity
273
What sizes do capacitors come in
15,25,50,150,200 KVA but 100,150 and 200 are the most common
274
Typical crystalline silicon cell produces how much power
Approximately 1 watt of power
275
When connecting closed wye,closed wye, why do you always connect the primary and the secondary neutral’s together
To prevent fluctuating voltage on the secondary side
276
What is the procedure to take out a transformer on a parallel circuit
Make sure the remaining transformer will hold the load, then take out the secondary legs and tape, take the high side off, then remove the neutral and the tank grounds
277
What is the laminated core made of on a transformer
Steel
278
Explain the procedure for paralleling 2 transformers
Check to make sure that they have the same phase and voltage rating, be within impedance percentage and polarity. If ok, then hook up grounds and neutral, then primary side, then phase in secondary side with voltmeter. Conductors are phased in when voltmeter reads zero
279
What is the current limiting properties of an inductor called
Inductive reactance
280
Rubber gloves cuffs are rate at what kva
10,000 volts per one inch
281
What is the purpose of rubber gloves sticking out of the protectors
To protect against flash over
282
What is the advantage of a wye over a delta system
A wye can carry 73% more load current than a delta and provides a balanced load
283
How do you determine the mechanical advantage using block and tackle
Count the number of lines not to include the fall line to determine the mechanical advantage
284
What is semicon for
Dispenses eddy currents
285
Why is it dangerous to a lineman to open a primary neutral
It may cause a fire because the neutral Carrie’s the unbalanced load of all the single or 3 phase circuits
286
In common distribution transformers, the tap changer is located in which coil
The primary
287
What is used when paralleling 2 secondary circuit
Voltmeter
288
Can the distribution transformer used in a 2400 volt, 3 wire delta system be used in a 3 phase, 4 wire 4160 volt wye system
Yes
289
What is the procedure for tagging
Identify, test, isolate,ground.
290
What is the procedure for tagging
Identify, test, isolate,ground.
291
T/F: a transformer whose secondary voltage rating is 240/120 volts has two independent coils, each rated 120 volts
False
292
T/f: a transformer bank whose secondary voltage readings to ground read -120,120,208 is connected wye
False
293
T/f- single phasing occurs when one fuse blows on a wye-delta bank with the primary neutral bus grounded
True
294
T/F: two wires of a delta primary feeder can be used to supply 3 phase to a customer.
False
295
T/f: when the secondary breaker is opened on a csp transformer, the primary becomes de-energized
False
296
T/F a 4160 volt transformer when used on a 2400/4160 volt systems requires only on cutout and arrestor
False, delta
297
T/f: a subtractive polarity transformer cannot be used in a Bank of additive polarity transformer
False
298
When using a test instrument to measure resistance, what 3 factors effect the amount of resistance
Resistance of the electrode, the contacts of resistance between the electrode-earth, resistance of the surround earth
299
How many indicating pointers does a maximeter have
Two
300
Can a maximeter be removed from a conductor, reset to zero and immediately be placed on another conductor
No, it must be allowed to cool
301
What determines the strength of the magnetic field in a circuit
The amount of current that flows through a conductor
302
Alternating circuits loads are generally described as being
Resistive, inductive, capacitive loads
303
List 3 factors which determine the amount of voltage that will be induced in a conductor
The size, type and length of the conductor
304
What are 3 factors determine the capacitance of a capacitor
The area of plates, the distance between the plates and the type of dielectric used
305
List 4 types of controls that are used with capacitors
Time switched, time temp, voltage and current
306
List 5 factors which effect the amount and type of capacitor banks installed on distributon circuits
Length of the circuits, residential lines, rural lines, commercial lines, industrial lines
307
What do you do when you size up a distribution job
Identify all the hazards on the pole
308
Names 3 types of wire ring saddles
Pole type saddles, cross are saddles, tower saddles
309
When does a recloser usually lock out??
After 4 operations
310
The most common defect in insulators are
Cracks in the porcelain
311
What is the national electrical code definition of medium voltage ranges
From 2001-3500 volts
312
Define splice
The joining of two of more conductors
313
List 3 major components of an implosive compression splice for an scar conductor
Steel inner sleeve, aluminum sleeve outer, aluminum sleeve
314
What happens if a lead wire supplying on lamp in a series circuit is broken
It interrupts the entire circuit
315
Define Lumen
One unit of light output
316
What is a reflector made of?
Porcelain, metal,silvered glass
317
Gaseous conductor lamps have a circuit limiting devices called
Ballasts (choke coils)
318
A fluorescent lamp requires a____ to limit circuit during operations
Ballast
319
Which direction with the motor turn if a phase sequence of a 3 phase system is 321
Counter-clockwise
320
If a line is balanced with 10 amps on a a phase and on b phase and on c phase how many amps are on the neutral
0 amps
321
What does getting in series mean
It is getting between the line and load or between the line and ground or between the line and the line essence becoming a human Mack
322
How many bushings does a 277/480 can have in the secondary side
2 bushings
323
What is a 3 phase transformer
3 single phase transformer in one can using one core
324
What does the term frequency mean in a relationship to AC circuit and voltage
It is the number of complete cycles in one second shown by a sine wave
325
What are the current limiting properties of an inductor called
Inductive reactance measured in ohms
326
If one circuit is regulated and the other is unregulated can they be tired together with out other immediate action
No the circuit that is regulated must be set to zero before they can be tied in with phasing set
327
Explain the procedure for removing grounds on a distribution or transmission line
Furthest to nearest then ground
328
In a wye underground system shielded cable requires the installation of a neutral where concentric cable does not
Cable that does not come with a built in concentric cable requires a neutral to be laid next to it
329
Apparent power is
The total power supplied in a circuit, apparent power is a combination of active power and reactive power
330
Power factor
The ratio of active power to apparent power
331
Which side of the pole is the face
The concave or inside of the sweep or bow
332
Which side is the back
The convex side
333
Where does the framing and equipment go on the wood pole
The face
334
#2 copper mac amapacity
230 amps
335
1/0 copper mac ampacity
310
336
2/0 copper mac copper mac amapcity
355
337
4/0 copper mac amapcity
480
338
Carbon in oil in a transformer is a indication of what?
Arcing
339
How many volts per foot is a hot stick tested at?
100,000 per foot
