Step 7 Flashcards
Define transformer
An electrical device that raises or lowers voltage depending on the costumers needs
Define Capacitor
A device that stores energy by means of electrostatic charge
Constant current Transformer (R.O.)
A transformer that automatically maintains a constant current in its secondary circuit under varying load
Multiple street lights are connected in _____
Parallel
Most accidents are caused by defective equipment
False
A 4160 volts or star circuit has a phase to voltage of ______
Formula: voltage/1.73
4160/1.73 = 2400
Working on transformers in parallel operations
Secondary side should be open first and closed last
Whats the maximum resistance a ground should have?
25 Ohms
what must be done to voltage regulators before 2 regulated circuits can be phased and tied together
They must be placed on neutral and locked out
Whats 2 purposes does oil in a transformer serve?
- Insulation
2. Cooling
What does KVAR mean
Kilo Volt Amper Reactance
All personal working on jobs that require the use of a helicopter will be briefed by the pilot and or supervisor as to their duties and safety precaution to be taken
True
A customer complains of flickering lights what are two probable cause?
1) . Loose connections
2) . Wires touching
When a line hose or rubber blanket is lowered from a pole it should be set aside anyplace out of the way.
False
What are three types of faults that occur most often
1) . Phase to phase
2) . Phase to ground / neutral
3) . Open
what precautions must be taken when connecting a current transformer?
Make sure grounds are off and secondary are connected
Bond wires shall be not less than ___ inches from metal braces.
1 1/2 inches
The difference between primary fuses marked “T”, “E” or “K” is the melting time of the links to open
True
The climbing space on a pole shall be maintained in the same position for a distance of no less than ____ feet vertically both above and below each conductor level through which it passes.
4
what must be done to the voltage regulators before two regulated circuits can be phased and tied together?
They must be placed on Neutral and locked out.
What is meant by the interrupting capacity of a breaker
The point at which it trips the maximum amperage it can carry
Shock is pressent in all cases of severe bleeding.
False
After reaching the victim of a pole top accident what is the first action to be taken?
Carefully clear vicim from energized equipment
Rubber goods should be relied on for accidental contact only
True
Compressions in a sleeve used to splice conductors are made.
Starting at the center and working outward
What is meant by “Blocking Reclosures?
Same as one shot
The minimum safe working distance from a 12,000 volt circuit is _____
2’1”
A multiple street light can be connected to any convenient secondary of proper voltage and does not require its own transformer.
False
Rubber goods should not be left on conductors overnight because
all of the above
The worst enemy of a Hot Stick is
Moisture
The strength of a pole is expressed as is
Class
On a 12,460 volt grounded why system 7,200 volt transformer are connected ____
Phase to Neutral
A three phase delta system has no grounds on it. One phase accidentally grounded. What happens?
Nothing
Two transmission lines exist on the same tower. If one is energized and the other is switched out and de-energized the voltage induced
Could Kill you
What is the total load on the block in the following diagram
14,340
In an open (two transformer) three phase bank the secondary:
Must be connected delta
URD defines what?
Underground Residential Distribution
The grounding conductor on a portable tool is
Green
A sagging chart is used to
Show initial sag and tensions for sag throughout a line where tension is used in all spans
Transformer fuses protect equipment from what?
Surge on the line
Briefly define back-feed
When power is feed from the secondary side to the primary
If it should ever become necessary to open a common neutral in a common neutral system, what must be done?
Mack it out and work it hot
Transformer tap changer
Raise and lower output voltage of a transformer
A transformer with built in protection for overhead is called what type of transformer
CSP
Before working on a capacitor bank you should?
Disconnect the bank from the source, wait 5 min, shunt out each capacitor and ground
A fusitor is used to
Limit Current
What is Osha
Occupational Safety and Health Administration (OSHA) is a federal organization that ensures safe and healthy working conditions
When is a line considered De-energized
When its been tested and grounded
Define climbing space (G.O.95)
An area reserved for the lineman to ascend and descend in a safe manner.
What is the proper way of securing a 15 KV blanket
clothes -pins
You ar operating the puller on a wire stringing job and the puller begins to drag down and you notice the rope is getting extremely tight what should you do
Hold the pull and communicate to see if it is stuck somewhere
A sectionalizer must be used in conjunction with what electrical apparatus
Automatic reclouser
Two 10 KVA transformers are in parallel operation and you get a trouble call because on unit is smoking. When you arrive both units are still working. One unit is boiling and the other is cool. The connected load does not exceed the 20 KVA capacity of the two units. What are two possible problems?
- ) Oil is low
2. ) the impedance values are off
If you suspect a fracture of the lower leg what part do you keep from moving
the whole leg
Rubber goods should be relied on for accidental contact only.
True
The conductor you put rubber goods on first is
Conductor nearest you
you are working on a line crew when an accident occurs the foreman sends you to summon help who should you call and what info should you give them?
Call 911 Let them know my Name location status on injured personal what first aid has been given if a helicopter can land
