HIGH VOLTAGE OPERATIONAL LEVEL EXIT EXAM QUESTIONS AND ANSWERS 1.0

• Which among the following are the typical HV system voltage used in the marine field ?

1. 2.6 KV
2. 3.2 KV
3. 6.4 KV
4. 11 KV                      *

• Brushless generators are designed to operate without the use of

1. Brushes
2. Slip rings
3. Commutators
4. All of the above                  *

• The fault current is exceptionally low for __________

1. HV supplies                   *
2. LV supplies
3. Both HV and LV
4. None of these

• The induced voltage across a stationary conductor in a steady magnetic field is zero

1. True                         *
2. False

• The HV switches can be operated by _______

1. Anyone
2. Authorised person only                  *
3. Chief engineer only
4. None of these

• High voltage switchboard can be earthed down using two methods circuit earthing and ______

1. Resonant earthing
2. Busbar earthing                  *
3. Resistance earthing
4. None of the above

• An electrical device which prevents an action from occurring until all other required conditions are met is called a/an __________

1. Limit
2. Monitor
3. Modulator
4. Interlock                     *

• How is COVID-19 passed on ?

1. Through droplets that come your mouth and nose when you cough or breathe out               *
2. In sexual fluids, including semen, vaginal fluids or anal mucous
3. By drinking unclean water
4. All of the above

• The __________ are commonly used for measurements of peak values of high voltages

1. Sphere gaps                *
2. Voltage difference
3. Current
4. None

• The physical separation of two parts of a device or equipment is called as ________

1. Enclosure
2. Isolation               *
3. Insulation
4. Segregation

• Which allow to equalize power factor of two alternator ?

1. Governor
2. Automatic voltage regulator                   *
3. Syncroscope
4. None of these

• Circuit breakers and disconnects are used to de energize a high voltage source

1. True
2. False                   *

• Ground occur in the electrical machinery as a result of insulation failure

1. Deteration through moisture
2. Excessive heat
3. External period of vibration
4. All of the above             *

• Arc interruption is done by __________

1. High resistance interruption
2. Low resistance interruption
3. Both a and b                  *
4. None of the above

• If a cable becomes wet or it absorbs moisture, it will develop _______  resistance

1. Low insulation resistance                        *
2. High insulation resistance
3. Same as before
4. None of the above

• Ionization in circuit breakers is facilitated by ________

1. Increase of field strength
2. Increase of men free path
3. High temperature
4. All of these                         *

• ________– contains the shipyard’s description of operations regarding the vessels’s HV equipment

1. Preliminary operation manual                *
2. High voltage operation manual
3. Performance manual
4. Equipment manual

• Regulation for design and installation of marine high voltage systems are governed by the _____________

1. International association of classification societies                  *
2. International maritime union
3. United maritime association
4. Marine electrical association

• The vacuum circuit breaker is applicable only for­­­­­­___________ voltage systems

1. Very low
2. Low
3. Medium                      *
4. High

• The proof test voltage of class 1 in selecting rubber gloves is _______

1. 2500 AC / 10000 DC
2. 10000 AC / 40000 DC                      *
3. 5000 AC / 10000 DC
4. 1000 AC / 20000 DC

• Low voltage circuit breakers have rated voltage less than ______

1. 220 V
2. 440 V
3. 1000 V             *
4. 10000 V

• Arcing does not occur in heavy current flow to earth during an earth fault or short circuit fault

1. True
2. False                     *

• Air blast circuit breakers are preferred for ________

1. Short duty
2. Intermittent duty
3. Repeated duty                           *
4. All of these

• Which of the following is false with regard to electric shock  ?

1. When high voltage of about 50 volt is applied through the human body it results in heart fibrillation
2. Electric shock occurs when a person touches an improperly insulated dead conductor                        *
3. The human body has a resistance and impedance to the flow of electrical current
4. The impedance of the body of a person depends on the voltage applied

• A fuse that blows often should be replaced only with a fuse of

1. The recommended current and voltage rating                               *
2. Higher current and voltage rating
3. Higher current and lower voltage rating
4. Lower current and higher voltage rating

• The extremely light and heat produced by the arc is known as ________

1. Arc flash                  *
2. Arc blast
3. Arc quench
4. Arc light

• With regard to flow of current through the body 0.015 A is the ________ current

1. Tickling
2. Let go                      *
3. Dangerous
4. Lethal

• PI test is conducted for low voltage generators

1. True
2. False                   *

• What is polarisation index ?

1. Ratio of 10 min resistance to 1 minute insulation resistance                             *
2. Ratio of 1 min resistance to 10 minute insulation resistance
3. Ratio of 5 min resistance to 25 minute insulation resistance
4. None of these

• Bathrooms should be adequately ventilated to avoid accumulation of explosive gases  Usually generated in the operation of batteries

1. True              *
2. False

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