电工技能鉴定考核试题库初级.doc

电工技能鉴定考核试题库(精选) 初级Electrician skill appraisal examination question bank (selected) primary worker-2004-6-20 0:10:15 browsing times: 12253-First, the right and wrong1 、 indicating instrument can not only measure the electromagnetic quantity directly, but also cooperate with various sensors to measure the non electric quantity of temperature, pressure and flow. (V)2 、 the electric meter can do both the direct current, the direct current and the higher accuracy ammeter, voltmeter, and also can do the success rate table, frequency meter and phase table. (V)3, the accuracy is 1.5 meters, the basic error of measurement is + 3%. (x)4, we should directly measure the average value of the current in the circuit, we can choose the electromagnetic system instrument. (x)5 、 the additional resistance of the voltmeter can not only extend the range of temperature, but also play the role of temperature compensation. (V)6, the voltage transformer two winding is not allowed to open circuit, current transformer two winding short circuit is not allowed. (x)7. DC ammeter can be used in AC circuit. (x)8, can be made not only on ammeter can measure AC current, DC current can be measured. (V)9, use a multimeter to measure resistance, every change to the pointer ohm files a transfer order. (V)10, measuring AC circuit and active power, because it is alternating current, so its voltage coil, current coil and two ends can be arbitrarily connected to the road. (x)11, with two single-phase power meter measuring three-phase three wire active load power, there is a table reversal, this must be wiring error. (x)12, the power system of the current coil coil counter, will lead to counter deflection of the needle, but if the voltage coil is also reverse, you can operate normally. (x)13 、 electromagnetic system instruments ability to resist external magnetic field interference is stronger than magnetoelectric instrument. (x)14, Department of electric meter phase did not produce reaction torque of the hairspring, so that the instrument without access to the circuit, the pointer can be stopped at any position on the dial. (V)15, according to the instrument on the electric field or external magnetic field defense ability, divided into I, II, III, IV four level. Under the influence of an external magnetic field or an electric field, the secondary instrument allows its indication value to be changed by + 1%. (V)16. Measure the current of ammeter, internal resistance is bigger, the better. (x)17, the internal resistance is not available multimeter ohm file direct measurement microammeters, standard cell or galvanometer. (V)18, whether the measured DC or AC electroscope, the neon lamp light gun is the same situation. (x)19, equipped with low-voltage electroscope neon bulb can distinguish line (line) and the ground, can also check out the AC or DC low voltage digital display; in addition to the inspection body charged with electroscope without electricity, but also for wire disconnection. (V)20, stripping pliers can be used to strip the insulation layer in the core area of load following 6mm2 plastic or rubber wire line, it should have a diameter of 6mm and the following incision. (x)21, the protection of electric iron, the wiring can be connected, or can not wiring. (x)22. Manual oil pressure connection pliers can be used to press copper and aluminum wires with 16240mm2 cross section. (V)23, when installing earth wire, should be installed three-phase line end, and then install the ground end; when the demolition of the opposite, first remove the ground end, and then remove the three-phase line end. (x)24, welding machine one or two wiring length should not exceed 20m. (x)25. The AC ammeter and voltmeter indicate all valid values. (V)26, insulation boots also can make acid, alkali resistance, rain boots use. (x)27, copper has good conductivity and thermal conductivity, high mechanical strength, but in testing higher easily oxidized, melting time is short, should be used as fast melt, protective transistor. (x)28, low melting point, long melting time of metal materials, tin and lead, suitable for high voltage fuse melt. (x)29, strong electricity contact and weak contact, the performance requirements are the same, the materials used are the same. (x)30. Aluminum nickel cobalt materials used as sensors, speakers and microwave devices are permanent magnets and can provide a constant magnetic field in a certain space. (V)31. When aluminum wires are joined, they can not be wrapped or twisted like copper wires, just because the mechanical strength of aluminum wires is poor. (x)32, the safety of wire flow at different environmental temperatures have different values, the higher the temperature, the greater the safe carrying capacity. (x)33, the steel core aluminum wire through the AC, due to the skin effect of alternating current, the current actually only flows through the aluminum wire, so the effective cross-sectional area is only part of the aluminum wire. (V)34, the resistance coefficient of soil, underground cables will affect the heat dissipation, thus affecting the safe carrying capacity of cable. Resistance coefficient is, the greater the safe carrying capacity of cable. (x)35 、 the cable tube (TC) and the tube wall are thin, its nominal diameter refers to its inner diameter. (x)36, bare wire laying height indoors must be more than 3.5m, less than 3.5m, not set up. (x)37, the wire laying in the ceiling or ceiling, can not wear tube protection. (x)38, short cable, traction hours, traction head can be used to allow the wire core to bear tension; when traction is large, you can use wire jacket traction. (x)39, all wear lines, pipe joints should not be more than 1. (x)40, the cable core sometimes suppressed round, semi-circular, fan-shaped and other shapes, this is to reduce the size of the cable, and save raw materials. (V)41. The protective layer of the cable is the conductor of the cable core. (x)42, the cable in the move, the cable tray should be placed flat in the car, in order to fixed. (x)43. In paper insulated cables, the working voltage of the wrapped lead cable is higher than that of the wrapped lead cable. (x)44, medium and low pressure PVC cables, polyethylene cables and XLPE cables, usually as well as paper insulated cables, have a fully sealed metal sheath. (x)45, cable in operation, as long as the load monitoring do not exceed the allowable value, does not need to monitor the temperature of the cables, which are both consistent. (x)46, the cable in the steel saw when the process is to use the diameter of 2.0mm, copper around 34 tie, steel a tight tie, copper wire winding direction should and steel armour winding is opposite. (x)47 、 when the power station is out of power, first pull the isolating switch, then cut off the breaker. (x)48, high voltage isolation switch in operation, if the insulator surface serious discharge or insulator rupture, should be immediately isolated high-voltage disconnecting switch, out of operation. (x)49 、 high voltage load switch has arc extinguishing device, it can break short circuit current. (x)50, the replacement of fuse tube quartz sand, quartz sand particle size is the same. (x)51, the standby transformer should also light gas relay into the signal circuit. (V)52, no load voltage transformer, in the transformer switch after switching, should be measured each phase winding DC resistance, each phase DC resistance difference is not greater than 10% of the three-phase minimum value is qualified. (x)53. Usually the shunt capacitor group discharges itself through the voltage transformer or the discharge bulb after the circuit is cut off. Therefore, after the power station is cut off, there is no need to carry out manual discharge, so that the maintenance work can be carried out. (x)54. After a period of use, the storage battery has found that the voltage of some batteries is very low, and most of the battery voltages are still high, and they can continue to be used. (x)55 、 electromagnetic over-current relay is instantaneous action, often used in circuit and equipment over-current protection or quick break protection. (V)56 、 the action time of inductive overcurrent relay is proportional to the square of the current flowing. (x)57 、 gas (gas) protection can not only reflect all kinds of faults in transformer oil tank, but also reflect some faults outside the tank. (x)58 、 the primary current of the current transformer depends on the two current, the two current is big, and the primary current is larger. (x)Melt 59, replacement of high voltage fuse, can be welded with tin or copper or silver shot, also available Pewter or silver, also can melt Pewter or zinc. (x)60, when the voltage transformer is in operation, its oil filling plug should be tightened. (x)61 、 vacuum circuit breaker is suitable for the indoor transformer substation and the industrial and mining enterprises in 35kV and below, which require frequent operation occasions and faults, and is especially suitable for breaking the capacitive load current. Its operation and maintenance is simple and noise is small. (V)62 shunt capacitor banks are allowed to operate at 1.1 times the rated voltage and allow longer than 30% of the rated current of the capacitor. (V)63 、 inductive overcurrent relay has the function of electromagnetic current relay, time relay, signal relay and intermediate relay. It can not only realize the over current protection with time limit,Moreover, the current fast breaking protection can be realized. (V)64, the general knife switch can not cut off the fault current, and can not withstand the electric and thermal effects caused by the fault current. (x)65, low voltage load switch (iron switch) can switch fast opening and closing of the knife, depends on the manual operation mechanism handle movement speed. (x)66. Apply the contactor (such as CJ12 Series), which is suitable for long distance working system, for long-term working, and reduce its capacity to less than half of the rated capacity. (V)67, contact silver and silver base alloy contact surface in breaking arc formation of black oxide film contact resistance is very large, should be file repair. (x)68 、 motors with frequent reverse rotation and frequent on-off operation are suitable for thermal relay protection. (x)69 、 plastic casing low-voltage circuit breaker is widely used in switch cabinet of industrial and commercial power distribution room, AC and DC distribution line. Frame type low voltage circuit breaker is mainly used to protect the motor and lighting circuit with little capacity, and is used as the control switch. (x)70, in flammable and explosive places of lighting lamps and lanterns, should use sealed or explosion-proof lamps and lanterns, in dusty, damp and corrosive gas place of lamps and lanterns, should use waterproof dustproof type. (V)71, dust, damp place or outdoor lighting switch, should use porcelain waterproof pull switch. (V)72. The rated capacity of a transformer refers to the apparent power output by a transformer. (V)73, the power phase (fire) line can be directly connected to the lamp, and the switch can control the ground wire. (x)74 、 safety voltage lighting transformer use double coil transformer, also can use autotransformer. (x)75, can be protected; single-phase three hole power socket grounding end (the top face of the socket) and zero connection terminal 9 left lower hole) connected by wires, sharing a line. (x)76. The power line is connected to the socket or connected to the plug. (x)77, screw cap phase (fire) line is connected to a lamp mouth center of the tongue, the zero line connected to the threaded port. (V)78. The rated voltage of the motor is the voltage of each phase of the input stator winding, not the voltage between the lines. (x)79. The dynamic stability and thermal stability conditions of the motor starting are reflected in the allowable starting condition of the motor (direct or step-down) and the number of times of continuous starting. (V)80 、 asynchronous motor adopts Y- delta step-down starting, the stator windings are connected by Delta, and then replaced by Y connection operation. (x)81. The short duration of the motor short-time operation system shall not exceed 10min. (x)82. The insulation level of the motor, which indicates the insulation material of the motor winding and the temperature tolerance that the conductor can bear. Such as class E insulation, which allows a maximum temperature of 120 degrees celsius. (V)83 、 the method of starting voltage reduction of autotransformer is suitable for capacity less than 320kW, cage type asynchronous motor frequently start. (x)84. Starting method of wound rotor asynchronous motor,Y- delta decompression is often used. (x)85, winding rotor asynchronous motor in heavy start and low speed operation, should choose frequent rheostat start. (x)86. The characteristics of the starting motor with frequent rheostat is that the resistance of the frequent rheostat can increase smoothly with the increase of the motor speed. (x)87, winding rotor non motor adopts rotor string resistance, when starting, the greater the resistance, the starting torque is greater. (x)88. Check the insulation resistance of the stator, rotor winding and winding to the ground of the low voltage motor stator. When measured with 500V insulation resistance, the value should not be lower than 0.5M, otherwise it should be dry treated. (V)89, for only a single operation, accident handling, pull the grounding switch and remove only a group of ground operations, can not fill in operation tickets, it should be recorded in the record of the operation. (V)90, the beginning of the operation of the handle on the lock, hang or remove signs must also be written into the operation ticket. (x)91, the operation of electrical equipment operation must be carried out by two people, the lower level of work as a guardian, the higher level of operation. (x)92, the operation of the transformer substation, hanging or dismantling the ground wire, test and installation voltage, transformer circuit fuse and other items can not fill in the operation of the ticket. (x)93, substation power failure operation, in the circuit after cutting off check work, may not fill in the operation ticket. (x)94, the wounded rescue shock, with excited respiratory Coramine, lobeline, or cardiac adrenergic and strong heart injection two emergency measures instead of manual breathing and external cardiac compression. (x)95, the power from the factorys total step-down change power distribution introduced by the factory two substation, transformer capacity of less than 500kVA, you can not set up on duty, only arrangements for patrol inspection. (V)96, electrical equipment after the blackout, before disconnect the power switch and take safety measures, must not touch the equipment or equipment into the cover column, so as to avoid the occurrence of electric shock accident. (V)97, R * 1 with a multimeter ohm test electrolytic capacitor, capacitor cathode the black pen, the red pen is connected to the anode, hands slowly increased, if the stop in 10K. And that the capacitor is good. (x)98, the forward voltage drop between the base of the germanium tube and the emitter is greater than the forward voltage drop of the silicon tube. (x)99. The butt joint of groove for thick plate shall be welded with thick welding rod on the first layer. (x)100, the horizontal fixed pipe fittings butt welding, can be used from the top clockwise or counter clockwise welding round welding method. (x)Two 、 choose questions (fill in the blanks with the correct answer number)1, the following instrument accuracy class grouping, can be used as engineering measuring instrument for the C group.A, 0.1, 0.2, B, 0.5, 1, C, 1.5, 2.5, 52, to measure the average value of nonsinusoidal alternating current, a meter should be used.A, rectifier system, B, electromagnetic serialization, C, magnetoelectric series, D, electric system3, a DC magnetoelectric meter, meter full scale 100A, external shunt with 100A, 75mV mark, 300A, now equipped with a shunt ammeter indication 75mV, 50A, C in the current actual line.A, 50A, B, 100A, C, 150A4, clamp meter should be used in a wide range, and then depending on the size of the measured current range transform. Switch range should be B.A, directly turn the range switch B, first open the jaw, then turn the ran