LADWP ELECTRIC STATION OPERATOR EXAM ACTUAL
EXAM 2026 (CIRCUIT BREAKERS, DISCONNECTS,
TRANSFORMERS) | ALL QUESTIONS AND CORRECT
ANSWERS | BRAND NEW VERSION!
Since they have no moving parts, the only losses are those caused by
field __________ when a transformer is energized, and resistance of
the core material. ---------CORRECT ANSWER-----------------excitation
Circulating currents, called __________ currents, cause unwanted
heating of the transformer and a loss of energy. ---------CORRECT
ANSWER-----------------Eddy
By laminating it, using thin sheet of __________ steel or other ferrous
alloys sprayed with an insulating material, eddy currents are greatly
reduced in transformers cores. ---------CORRECT ANSWER-----------------
silicon
The heat and accompanying loss of energy caused by friction of the
molecules is called __________. ---------CORRECT ANSWER-----------------
Hysteresis
,The losses of electrical energy that appear as heat and which are cause
by hysteresis and eddy currents in the magnetic core are known as
__________ losses. ---------CORRECT ANSWER-----------------iron
The losses due to the resistance of the windings care called _________
losses or I2R losses. ---------CORRECT ANSWER-----------------copper
The heat caused by iron and copper losses shortens the service life of
__________ materials used in transformer windings. This may cause
premature transformer failure. ---------CORRECT ANSWER-----------------
insulating
High temperature limits the __________ carrying capacity of
transformers. ---------CORRECT ANSWER-----------------current
_________ not only helps extend the life of transformers but also
increases its current carrying capacity. ---------CORRECT ANSWER----------
-------cooling
, Localized areas of greater heat are called __________. ---------CORRECT
ANSWER-----------------hot spots
Small and medium sized __________ are self-cooled; that is; cooling
takes place by direct radiation from the tank to the surrounding air. -----
----CORRECT ANSWER-----------------transformers
Transformer oil in good condition must be able to withstand _____kV
applied across two flat electrodes submerged in a staple of the oil
without arcing. ---------CORRECT ANSWER-----------------30
__________-ratio is the number of turns of wire in the primary winding
compared to the number of turns in the secondary winding. ---------
CORRECT ANSWER-----------------Turns
Station ___________ transformers are the distribution transformers for
substations. They provide the station with single-phase power for light,
etc. and three-phase power for such things as fans, pumps, gate motor,
compressors, etc. ---------CORRECT ANSWER-----------------service
EXAM 2026 (CIRCUIT BREAKERS, DISCONNECTS,
TRANSFORMERS) | ALL QUESTIONS AND CORRECT
ANSWERS | BRAND NEW VERSION!
Since they have no moving parts, the only losses are those caused by
field __________ when a transformer is energized, and resistance of
the core material. ---------CORRECT ANSWER-----------------excitation
Circulating currents, called __________ currents, cause unwanted
heating of the transformer and a loss of energy. ---------CORRECT
ANSWER-----------------Eddy
By laminating it, using thin sheet of __________ steel or other ferrous
alloys sprayed with an insulating material, eddy currents are greatly
reduced in transformers cores. ---------CORRECT ANSWER-----------------
silicon
The heat and accompanying loss of energy caused by friction of the
molecules is called __________. ---------CORRECT ANSWER-----------------
Hysteresis
,The losses of electrical energy that appear as heat and which are cause
by hysteresis and eddy currents in the magnetic core are known as
__________ losses. ---------CORRECT ANSWER-----------------iron
The losses due to the resistance of the windings care called _________
losses or I2R losses. ---------CORRECT ANSWER-----------------copper
The heat caused by iron and copper losses shortens the service life of
__________ materials used in transformer windings. This may cause
premature transformer failure. ---------CORRECT ANSWER-----------------
insulating
High temperature limits the __________ carrying capacity of
transformers. ---------CORRECT ANSWER-----------------current
_________ not only helps extend the life of transformers but also
increases its current carrying capacity. ---------CORRECT ANSWER----------
-------cooling
, Localized areas of greater heat are called __________. ---------CORRECT
ANSWER-----------------hot spots
Small and medium sized __________ are self-cooled; that is; cooling
takes place by direct radiation from the tank to the surrounding air. -----
----CORRECT ANSWER-----------------transformers
Transformer oil in good condition must be able to withstand _____kV
applied across two flat electrodes submerged in a staple of the oil
without arcing. ---------CORRECT ANSWER-----------------30
__________-ratio is the number of turns of wire in the primary winding
compared to the number of turns in the secondary winding. ---------
CORRECT ANSWER-----------------Turns
Station ___________ transformers are the distribution transformers for
substations. They provide the station with single-phase power for light,
etc. and three-phase power for such things as fans, pumps, gate motor,
compressors, etc. ---------CORRECT ANSWER-----------------service
