Circuit Breakers Part 4 Online MCQ EE

Circuit Breakers Part 4

Circuit Breakers Part 4

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Attempt Free Circuit Breakers Part 4 Here. Read The Important Electrical MCQ From Below.

Circuit Breakers Part Four (Fill In The Blank)

A sudden short-circuit in an ac system causes a rise in __________ in the short-circuited phase.
Answer: Current

The voltage appearing across the circuit breaker pole after final current zero is called __________ voltage.
Answer: Recovery

Thermal ionization of gases occurs at temperature around __________ C.
Answer: 3000

Circuit Breakers Part 4

The electron emission from contact surface caused by incidence of light energy is called __________.
Answer: photo-emission

De ionization can take place by the processes of recombination or attachment as well as by process of __________ and __________.
Answer: diffusion, drift

The behavior of arc in high vacuum is affected by contact material and __________.
Answer: conditions of the contact surface

Sphere gaps are used for measurement of __________.
Answer: high voltages

Current breakers are generally overhauled every __________ years.
Answer: three

Circuit Breakers Part 4

In circuit breakers, arc is extinguished either by __________ the arc __________ the arc or __________ the arc.
Answer: lengthening, cooling, splitting

Deterioration of dielectric oil is governed by __________ color.
Answer: dark

The characteristics of a fuse is governed by material and __________ of the fuse element.
Answer: shape

A fuse should generally have a normal rating 25 to 50 percent above the normal full load current to lake care of __________.
Answer: switching surges

Skin effect is absent in case of __________ current
Answer: direct

Insulators operate under __________ conditions.
Answer: no-load

Circuit Breakers Part 4

Melting point of aluminium is __________.
Answer: 657 C

Density of aluminium is nearly __________ of the density of copper.
Answer: one-third

Melting point of copper is __________ 0C.
Answer: 1083

Pantograph isolator is preferred for circuits above __________ kV.
Answer: 400

__________ current is the rms value of the current which a breaker must carry for a stated time.
Answer: short time

Circuit Breakers Part 4

The insulation requirements of switchgear are determined by __________ voltage.
Answer: transient

In horn gaps the arc is produced at the __________ during high voltage surge.
Answer: bottom

Secondary type lightning arresters are used for the protection of __________ transformers.
Answer: distribution

The non-linear resistor in lightning arrester offers __________ resistance to the flow of discharge currents and __________ resistance to power frequency voltage.
Answer:  low, high

The most severe cause of switching over-voltages is __________.
Answer: closing of charged line

Circuit Breakers Part 4

__________ type lightening arresters are designed to discharge the switching over-voltage as well as lightning over-voltages.
Answer: magnetically blow out type

Traveling wave gets reflected from short circuited line with reflected current wave of __________ polarity and voltage wave of the __________ polarity.
Answer: same, opposite

Peterson coil is the reactance used in __________ earthing.
Answer: resonant

The phenomena of arcing grounds is commonly experienced with __________ systems.
Answer: ungrounded

In solid grounding system, the neutral is connected to ground without any __________ between neutral and ground.
Answer: intentional impedance

The grounding is generally at the __________ end.
Answer: supply

Insulation co-ordination of EHV and UHV line is based on __________.
Answer: switch over voltages

Circuit Breakers Part 4

In delta connected load, the line current return path. Hence line currents __________ zero sequence component.
Answer: do not have

The negative sequence network has only negative sequence __________.
Answer: reactance

The smallest value of actuating quantity at which protection starts operating in relation with the minimum value of fault current in the protected zone, is known as __________ of the protective scheme.
Answer: sensitivity

Trip circuit is normally a part of __________.
Answer: circuit breakers

The time elapsed between the instant of occurrence of fault and instant of final arc extinction in circuit breaker is known as __________.
Answer: fault clearing time

The time interval between occurrence of fault and closure of relay contacts is known as __________.
Answer: relay time

Circuit Breakers Part 4

The lime interval between closure of trip circuit and final arc interruption is known as __________.
Answer: breaker time

Acting ground is also known as __________ fault.
Answer: earth

Phase fault is __________ fault.
Answer: line to line

A relay which responds to increase in current is known as __________.
Answer: over current relay

Power line carrier is a __________ signal sent through the power line conductors.
Answer: high frequency

Static relays __________ moving parts.
Answer: do not

An electro-magnetic relay will operate when operating force is __________ restraining force.
Answer: greater than

An electro-magnetic relay will operate when operating force is __________ restraining force.
Answer: greater than

Circuit Breakers Part 4

__________ is suitable for outdoor UHV and HV traction system.
Answer: Air blast circuit breaker

The drop off value to pick-up value of a relay is also known as __________.
Answer: holding ratio

The holding ratio of a relay is usually __________.
Answer: less than 1

A bimetal strip consists of two metal strips having different __________.
Answer: coefficient of thermal expansion

A directional relay senses __________.
Answer: power

Circuit Breakers Part 4