Circuit Breaker : Fill in the blanks with appropriate words : 1.

A sudden short-circuit in an ac system causes a rise in __________ in the short-circuited phase. Get Answer: (Hide) Current 2. The voltage appearing across the circuit breaker pole after final current zero is called __________ voltage. Get Answer: (Show) Recovery 3. Thermal ionization of gases occurs at temperature around __________ C. Get Answer: (Hide) 3000 4. The electron emission from contact surface caused by incidence of light energy is called __________. Get Answer: (Show) photo-emission 5. De ionization can take place by the processes of recombination or attachment as well as by process of __________ and __________. Get Answer: (Hide) diffusion, drift 6. The behavior of arc in high vacuum is affected by contact material and __________. Get Answer: (Show) conditions of the contact surface 7. Sphere gaps are used for measurement of __________. Get Answer: (Hide) high voltages 8. Current breakers are generally overhauled every __________ years. Get Answer: (Show) three 9. In circuit breakers, arc is extinguished either by __________ the arc __________ the arc or __________ the arc. Get Answer: (Hide) lengthening,cooling,splitting 10. Deterioration of dielectric oil is governed by __________ color. Get Answer: (Show) dark 11. The characteristics of a fuse is governed by material and __________ of the fuse element. Get Answer: (Hide) shape 12. A fuse should generally have a normal rating 25 to 50 percent above the normal full load current to lake care of __________. Get Answer: (Show) switching surges 13. Skin effect is absent in case of __________ current. Get Answer: (Show) direct 14. Insulators operate under __________ conditions. Get Answer: (Hide)

no-load 15. Melting point of aluminium is __________. Get Answer: (Show) 657 0C 16. Density of aluminium is nearly __________ of the density of copper. Get Answer: (Hide) one-third 17. Melting point of copper is __________ 0C. Get Answer: (Hide) 1083 18. Pantograph isolator is preferred for circuits above __________ kV. Get Answer: (Show) 400 19. __________ current is the rms value of the current which a breaker must carry for a stated time. Get Answer: (Hide) short time 20. The insulation requirements of switchgear are determined by __________ voltage. Get Answer: (Hide) transient 21. In horn gaps the arc is produced at the __________ during high voltage surge. Get Answer: (Show) bottom 22. Secondary type lightning arresters are used for the protection of __________ transformers. Get Answer: (Hide) distribution 23. The non-linear resistor in lightning arrester offers __________ resistance to the flow of discharge currents and __________ resistance to power frequency voltage. Get Answer: (Show) low,high 24. The surge current which flows through the lightning arrester after the spark over is expressed in terms of __________ value. Get Answer: (Show) peak 25. The most severe cause of switching over-voltages is __________. Get Answer: (Hide) closing of charged line Get all answers at once: (Show) 1.Current ----- 2.recovery ----- 3.3000 ----- 4.photo-emission ----- 5.diffusion, drift----- 6.Conditions of the contact surface----7.high voltages----- 8.three -----9.lengthening,cooling,splitting -----10.dark -----11.shape ----- 12.switching surges-----13.direct -----14.no-load ----- 15. 657 0C ----- 16. one-third----- 17.1083 ----- 18.400 ----- 19.short time----- 20.transient ----- 21. bottom----22.distribution ----- 23.low,high ----- 24.peak ----- 25.closing of charged line

Circuit Breaker : Fill in the blanks with appropriate words : 26 __________ type lightening arresters are designed to discharge the switching over-voltage as well as lightning over-voltages. Get Answer: (Show) 27. Traveling wave gets reflected from short circuited line with reflected current wave of __________ polarity and voltage wave of the __________ polarity. Get Answer: (Show) 28. Peterson coil is the reactance used in __________ earthing. Get Answer: (Show) 29. The phenomena of arcing grounds is commonly experienced with __________ systems. Get Answer: (Show) 30. In solid grounding system, the neutral is connected to ground without any __________ between neutral and ground. Get Answer: (Show) 31. The grounding is generally at the __________ end. Get Answer: (Show) 32. Insulation co-ordination of EHV and UHV line is based on __________. Get Answer: (Show) 33. In delta connected load, the line current return path. Hence line currents __________ zero sequence component. Get Answer: (Show) 34. The negative sequence network has only negative sequence __________. Get Answer: (Show) 35. 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. Get Answer: (Show) 36. Trip circuit is normally a part of __________. Get Answer: (Show) 37. The time elapsed between the instant of occurrence of fault and instant of final arc extinction in circuit breaker is known as __________. Get Answer: (Show) 38. The time interval between occurrence of fault and closure of relay contacts is known as __________. Get Answer: (Show) 39. The lime interval between closure of trip circuit and final arc interruption is known as __________. Get Answer: (Show) 40. Acting ground is also known as __________ fault. Get Answer: (Show) 41. Phase fault is __________ fault. Get Answer: (Show) 42. A relay which responds to increase in current is known as __________.

Get Answer: (Show) 43. Power line carrier is a __________ signal sent through the power line conductors. Get Answer: (Show) 44. Static relays __________ moving parts. Get Answer: (Show) 45. An electro-magnetic relay will operate when operating force is __________ restraining force. Get Answer: (Show) 46. __________ is suitable for outdoor UHV and HV traction system. Get Answer: (Show) 47. The drop off value to pick-up value of a relay is also known as __________. Get Answer: (Show) 48. The holding ratio of a relay is usually __________. Get Answer: (Show) 49. A bimetal strip consists of two metal strips having different __________. Get Answer: (Show) 50. A directional relay senses __________. Get Answer: (Show) Get all answers at once: (Hide) 26.magnetically blow out type ----- 27.same,opposite ----- 28. resonant ----- 29.ungrounded ----- 30.intentional impedance ----31.supply ----- 32.switching over voltages----- 33.do not have----- 34.reactance ----- 35.sensitivity ----- 36. circuit breakers 37. fault clearing time----- 38. relay time----- 39. breaker time---------- 40.earth ----- 41.line to line----- 42.over current relay----43.high frequency----- 44.do not----- 45. greater than----- 46. Air blast circuit breaker----- 47. holding ratio----- 48. less than 1 ---- 49. coefficient of thermal expansion----- 50. power