Electrician vocational qualification certificate exam simulation test - Database & Sql Blog Articles

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Single choice question
1. Among the following options, which are part of the corporate culture function (B)
A, physical exercise B, integrated function C, song and dance entertainment D, social communication
2. The role of professional ethics in the business (C)
A. Determine economic benefits B. Promote scientific decision-making C, enhance competitiveness D, and establish employee awareness
3. Among the following options, the correct discussion about the relationship between professional ethics and the success of a person's career is (A)
A. Professional ethics is an important condition for the success of a person's career. B. A person with a high level of professional ethics is sure to succeed in his career.
C. People who lack professional ethics are more likely to succeed in their careers. D. The success of a person’s career is not related to professional ethics.
4. In the professional ethics activities, the (C) is to meet the specific requirements of the language standard.
A, the words are meticulous, repeatedly introduce B, the speed of speech is fast, do not waste the guest time C, use the honorary name, do not have to remember
D, serious tone, maintain self-esteem
5. (A) is the inherent requirement of a company's honesty and trustworthiness.
A. Maintain corporate reputation B, increase employee welfare C, pay attention to economic benefits D, and carry out employee training
6. In the following discussion about hard work and thrift, the correct option is (B)
A, hard work must make people rich B, hardworking and thrifty is conducive to the sustainable development of enterprises C, the new era needs to work hard, do not need hard work D, new era needs to create, no need for thrift
7. In the production and management activities of enterprises, measures to promote equal respect among employees are (B)
A. Mutual benefit, equal distribution B, strengthen communication, equal dialogue C, as long as cooperation, do not compete
D, people are speculative, act cautiously
8. Inside the power supply, the negative pole points to the positive pole, ie from (D)
A, high potential points to high potential B, low potential points to low potential C, high potential points to low potential D, low potential points to high potential
9. The potential is a relative quantity that changes with the change of the reference point, and the voltage is (C), which does not change with the change of the test point.
A, measure B, variable C, absolute amount D, relative amount
10. The resistors of (A) are connected end to end, and the junction without branches in the middle is called series connection of resistors.
A, two or more B, two C, two or more D, one or more
11. When current flows through the load, the load converts the electrical energy into (D)
A, mechanical energy B, thermal energy C, light energy D, other forms of energy
12. The total electric charge when the capacitors are connected in parallel is equal to the amount of charge on each capacitor (D)
A, equal B, sum of reciprocals C, inversely proportional to D, sum
13. At (B), the magnetic field lines point from the S pole to the N pole.
A, external magnetic field B, internal C of the magnet, D at both ends of the magnetic field, one end of the magnetic field to the other end
14. The number of magnetic lines perpendicular to a section of the magnetic field is called flux or flux, in units of (B)
A, TB, φ C, H/m D, A/m
15. The direction of the force applied to the straight conductor in the magnetic field can be judged by (D).
A, right hand rule, left hand rule B, Lenz law C, right hand rule D, left hand rule

17. The basic steps for reading the picture are: (A), look at the circuit diagram, and see the installation wiring diagram.
A, the pattern description B, see the technical description C, see the pattern description D, the component list
18. The step-down start of the stator winding string resistance means that the resistor is connected in series between the stator winding of the motor and the power supply when the motor is started, and the starting voltage on the stator winding is reduced by the action of the resistor (C).
A, split B, pressure drop C, partial pressure D, partial pressure, split
19. Multi-range (C) is a voltmeter with a variety of resistance voltage doublers available in the table.
A, ammeter B, resistance meter C, voltmeter D multimeter
20. The range of the AC voltage is 10V, 100V, 500V, and third gear. Use the multimeter's transfer switch to (D) to avoid damaging the meter the next time you use it.
A, low resistance file B, low resistance file C, low voltage file D, high voltage file
21. The heat resistance grade of the insulating material and the maximum allowable temperature, the grade code is 1, the heat resistance grade A, and its allowable temperature is (B)
A, 900 B, 105 0 C, 120 0 D, 1300
22. (C) Suitable for slashing in narrow and long planes and when the machining allowance is small.
A, forward 锉B, cross 锉C, push 锉D, curved surface boring
23. (D) When the power frequency current passes through the human body, it is life-threatening.
A, 0.1mA B, 1mA C, 15mA D, 50Ma
24. In a power grid system where the power supply is short-circuited to ground, the potential difference between the point at which the human body touches the live equipment of the outer casing and the ground level is called (C).
A, single-phase electric shock B, two-phase electric shock C, contact voltage electric shock D, stride voltage electric shock

25. The safety voltage when using electrical equipment in wet places is (D)
A, 9V B, 12V C, 24V D, 36V
26. The outdoor of the high-voltage equipment must not be within the point of failure (D).
A, 5 m B, 6 m C, 7 m D, 8 m
27. Among the following forms of pollution that are not ecologically disruptive (D)
A. Forest destruction B, soil erosion C, water depletion D, land subsidence
28. Among the following forms of electromagnetic pollution that are not artificially electromagnetic pollution are (D)
A, pulse discharge B, electromagnetic field C, radio frequency electromagnetic pollution D, magnetic storm
29. Noise can be divided into aerodynamic noise, (D) and electromagnetic noise.
A, power noise B, water noise C, electrical noise D, mechanical noise
30. The quality requirements of the post usually include operating procedures, work content, (C) and parameter control.
A, work plan B, work purpose C, process code D, operation focus
31. The basic rights of workers include (D), etc.
A. Complete labor tasks B, improve vocational skills C, observe labor discipline and professional ethics D, receive vocational skills training
32. The basic obligations of workers include (A) and so on.
A. Obey labor discipline B, get labor compensation C, rest D, vacation
33. The electrician's instructions are divided into (C) and so on according to the structure and working principle of the meter measuring mechanism.
A, DC instrument welding and voltmeter B, ammeter and AC instrument C, magnetoelectric instrument and electric instrument D, installed instrument and portable instrument
34. When the electrician indicates that the meter is in use, it usually determines the purpose according to the accuracy level of the meter. For example, the 0.5 level meter is often used for (B)
A, standard table B, laboratory C, engineering measurement D, industrial measurement
35. The accuracy level of the DC system meter is generally not less than 1.5. In the absence of the 1.5 level meter, the 2.5 level meter can be used to adjust the error to the (C) standard under normal conditions.
A, 0.1 level B, 0.5 level C, 1.5 level D, 2.5 level
36. For current or voltage measurements, Class (D) and Class 2.5 instruments are permitted to use Class 1.0 transformers.
A, 0.1 level B, 0.5 level C, 1.0 level D, level 1.5
37. Electronic instruments can be divided into manual, remote control, program, automatic and other instruments according to (D).
A, function B, working frequency band C, working principle D, operation mode
38. With the rapid development of measurement technology, the range of electronic measurement is moving toward a wider frequency band and (D) direction.
A, ultra low frequency band B, low frequency band C, ultra high frequency band D, full frequency band
39. When the X6132 universal milling machine stops the spindle, press the stop button SB2-1 or SB2-1 to cut off the power supply circuit of the contactor (A) coil, and turn on the YC1 spindle brake electromagnetic clutch, the spindle can stop rotating immediately.
A, KM1 B, KM2 C, KM3 D, KM4
40. When the X6132 universal milling machine feeds motion, the up and down movement of the lifting platform and the back and forth movement of the table are completely controlled by the handlebar through the stroke switch. Among them, the stroke switch for controlling the table and moving upward is (D)
A, SQ1 B, SQ2 C, SQ3 D, SQ4
41. The left and right movement of the X6132 universal milling machine table is controlled by the joystick. The linkage mechanism controls the travel switches SQ1 and SQ2, which respectively control the table (D) and move to the left.
A, up B, down C, backward D, right
42. X6132 universal milling machine table forward (B) handle pressure SQ3 and work table to the right handle pressure SQ1, turn on the contactor KM3 coil, that is, the feed direction is selected according to the selected direction.
A, up B, down C, backward D, forward
43. X6132 universal milling machine table conversion feed speed is, when the mushroom-shaped handle is pulled forward to the extreme position and pushes the travel switch (D) by the orifice plate before the reverse push back, the contactor KM3 is instantaneously turned on, then The motor is momentarily rotated to make the gears easy to mesh.
A, SQ1 B, SQ3 C, SQ4 D, SQ6#p# page title #e#

44. After the X6132 universal milling machine spindle is started, if the quick button SB5 or (D) is pressed, the contactor KM2 coil power supply is turned on, the YC3 fast clutch is turned on, and the YC2 feed clutch is turned off, and the table moves rapidly according to the original moving direction. .
A, SB3 B, SB4 C, SB2 D, SB6
45. After the X6132 universal milling machine spindle is finished, turn the transfer switch to the (B) position and the spindle can be started.
A, turn on B, disconnect C, middle D, limit
46. ​​In the X6132 universal milling machine control circuit, the machine tool illumination is supplied by the Lighting transformer and the lighting itself (C).
A, main circuit B, control circuit C, switch D, no special
47. In the grinding wheel motor control circuit of the MGB1420 universal grinding machine, the power switch QS1 is turned on, and the 220V AC control voltage controls the contactor KM1 through the switch (B), thereby controlling the hydraulic pressure and cooling pump motor.
A, SA1 B, SA2 C, SA3 D, QS3
48. In the inner and outer grinding wheel motor control circuit of MGB1420 universal grinding machine, turn on the power switch QS1, 220v AC control voltage through the switch SA3 to control the opening and closing of the contactor (B) to achieve the start and stop of the inner and outer grinding wheel motor.
A, KM1 B, KM2 C, KM3 D, KM4
49. In the workpiece motor control circuit of the MGB1420 universal grinding machine, the start, jog and stop of M are realized by the master switch (A) controlling the intermediate relays KA1 and KA2.
A, SA1 B, SA2 C, SA3 D, SA4
50. In the workpiece motor control circuit of the MGB1420 universal grinding machine, when the main switch SA1 is tested, the intermediate relay KA1 coil is engaged, and the given signal voltage is drawn from the potentiometer (D), and the brake circuit is cut off.
A, RP1 B, RP2 C, RP4 D, RP6
51. In the automatic cycle working circuit system of MGB1420 universal grinding machine, through micro switch SQ1, SQ2, travel switch SQ3, universal transfer switch (D), time relay KT and solenoid valve YT cooperate with oil circuit and mechanical aspect to achieve grinding Automatic cycle work.
A, SA1 B, SA2 C, SA3 D, SA4
52. In the MGB1420 universal grinding machine, the workpiece motor speed of this system is (C)
A, 0~1100r/min B, 0~1900r/min C, 0~2300r/min D, 0~2500r/min
53. In the main circuit of the MGB1420 universal grinder thyristor DC speed control system, the rectifier transformer is used to directly rectify 220V AC, and the highest output voltage (B) is about.
A, 110V B, 190V C, 220V D, 380V
54. In the basic part of the control loop of the MGB1420 universal grinder thyristor DC speed control system, (A) is the power amplifier.
A, V33 B, V34 C, V35 D, V37
55. In the auxiliary link of the control loop of the MGB1420 universal grinder thyristor DC speed control system, V19 and (A) form a positive feedback link.
A, R26 B, R29 C, R36 D, R38
56. In the auxiliary link of the control loop of the MGB1420 universal grinder thyristor DC speed control system, the voltage differential negative feedback link is composed of (D), R37, R27, RP5, etc. to improve the dynamic characteristics of the motor during operation.
A, C2 B, C2 C, C2 D, C2
57. In the auxiliary link of the control loop of the MGB1420 universal grinder thyristor DC speed control system, the voltage negative feedback circuit is composed of R29 and R36(D).
A, R27 B, R26 C, R37 D, R38
58. In the control loop of the MGB1420 universal grinder thyristor DC speed control system, the base of V36 is added with the forward DC voltage through R19 and V13 and the reverse of the secondary coil of transformer TC1 via V6 and (A). DC voltage.
A, V12 B, V21 C, V24 D, V29
59. In the MGB1420 universal grinder thyristor DC speed control system control loop power supply part, after V1 ~ V4 rectification and then through V5 (D) DC voltage, supply to the single junction transistor trigger circuit.
A, 7.5VB, 10V C, -15V D, +20V

60. When drawing an electrical schematic, the main line and the auxiliary line are usually separated, and the main line is drawn with a thick solid line on the left side of the auxiliary line or (A)
A, upper B, lower C, right D, any position
61. When analyzing auxiliary circuits of more complex electrical schematics, analyze them against (B).
A, main line B, control circuit C, auxiliary circuit D, interlocking and protection
62. Among the following causes of failure (B), the DC motor cannot be started.
A, the power supply voltage is too high B, the wiring error C, the brush holder position is not right D, the excitation loop resistance is too large
63. The causes of abnormal DC motor speed are mainly (D) and so on.
A, the surface of the commutator has oil B, wiring error C, non-excitation current D, excitation loop resistance is too large
64. When the temperature rise of the DC motor is too high, it is found that the stator and the rotor rub against each other. At this time, it should be checked (B)
A. Is the transmission belt too tight? B. Is the magnetic pole fixing bolt loose? C. Is the bearing and the shaft too loose?
D, the motor is fixed firmly
65. The main reasons for the heating of DC motor rolling bearings are (A) and so on.
A, the bearing and the bearing chamber are too loose B, the bearing deformation C, the motor is damp D, the brush holder position is wrong
66. When checking the open winding fault of the wave winding, in the six-pole motor, there should be (B) black spots burned on the commutator.
A, two B, three C, four D, five
67. When the test light is used to check the short circuit fault of the armature winding to the ground, if the light is on, the armature winding or commutator (A)
A, short circuit to ground B, open circuit C, ground D, damage
68. When the commutator surface is repaired, the depth of cut is (A)
A, 0.05~0.1mm B, 0.1~0.15mm C, 0.2~0.25mm D, 0.25~0.3mm
69. When measuring the pressure of the brush with a spring balance, the pressure of the general motor brush is (A)
A, 0.015~0.025MPa B, 0.025~0.035MPa C, 0.035~0.04MPa D, 0.04~0.045MPa
70. When measuring the insulation resistance of a DC motor with a rated voltage of 500V or higher, use (B) an insulation resistance meter.
A, 500V B, 1000V C, 2500V D, 3000V
71. The DC servo motor has a large impact when it rotates. The reason is as follows: when the speed measuring generator is at (C), the peak value of the output voltage ripple is greater than 2%.
A, 550r/min B, 750r/min C, 1000r/min D, 1500r/min
72. In the common faults of the commutatorless motor, there is vibration in the motor feed. This phenomenon belongs to (B)
A, false alarm fault B, rotor position detector fault C, electromagnetic brake fault D, wiring fault
73. When the electromagnetic speed regulating motor is tested and tested, the drag motor can generally start at full pressure. If the power supply capacity is insufficient, (C) can be used for decompression starting.
A, string resistance B, star-triangle C, self-turning transformer D, extended triangle
74. When the commutator is inspected before assembly, the coaxiality difference between the commutator and the bearing block should be less than 0.03mm. During the rotation, the yaw should be less than (B).
A, 0.03mm B, 0.05mm C, 0.09mm D, 0.12mm
75. When adjusting the compensation degree of the magnetic motor expansion machine, when the load is a DC motor, the degree of under-compensation should be much less, which is often a full-compensation characteristic (C).
A, 75% B, 80% C, 90% D, 100%
76. The main reason for the low or no output voltage of the AC motor amplifier is (A)
A, control winding open circuit B, commutating winding short circuit C, compensation winding over compensation D, commutation winding reverse
77. All motors of the X6132 universal milling machine cannot be started, probably due to (C).
A, stop button normally closed contact short circuit B, SQ7 normally open contact bad contact C, SQ7 normally closed contact bad contact
D, electromagnetic clutch YC1 no DC voltage
78.X6132 universal milling machine spindle does not brake when it stops. If the DC voltage of the spindle electromagnetic clutch YC1 is low, there may be a partial short circuit inside the (A) coil.
A, YC1 B, YC2 C, YC3 D, YC4#p# page title #e#
79. When the X6132 universal milling machine spindle motor is started, and the feed motor cannot be started, the contactor KM3 or KM4 cannot be sucked, then it should be checked (A)

A. Is the contactor KM3, KM4 coil broken or B, and the motor M3's incoming terminal voltage is normal?
C. Whether the fuse FU2 is blown, D, the main contacts of the contactors KM3, KM4 are in poor contact
80. When the X6132 universal milling machine table cannot be fed fast, check whether the contactor KM2 is sucked. If it has been sucked, it should be checked (B)
A, KM2 coil is in contact with bad B, KM2 main contact is not in contact
C. Whether the contact of the quick button SB5 is in contact with the bad D, and the contact of the quick button SB6 is in poor contact.
81. During the electrical troubleshooting of the MGB1420 grinding machine control circuit, the automatic cycle grinding process cannot be automatically stopped. It may be that the time relay (B) is damaged and can be repaired or replaced.
A, KA B, KT C, KM D, SQ
82. When measuring the forward resistance between the control electrode and the cathode with a multimeter, the general reverse resistance is larger than the forward resistance, the forward direction is several tens of ohms or less, and the reverse direction is (B) or more.
A, tens of ohms or more B, hundreds of ohms or more C, thousands of ohms or more D, tens of thousands of ohms or more
83. In the common fault of the thyristor speed control circuit, the workpiece motor does not turn, it may be (C)
A, triode V35 leakage current is too large B, triode V37 leakage current is too large C, current cutoff negative feedback is too strong
D, the triode has been broken down
84. When measuring the insulation resistance of a coil with a rated voltage of 500V or less, a megohmmeter with a rated voltage of (A) should be used.
A, 500V B, 1000V C, 2500V D, 2500V or more
85. The clamp ammeter can only clamp one wire per measurement and place the wire in the jaw (C) to improve measurement accuracy.
A, upper B, lower C, central D, any position
86. When using the PF-32 digital multimeter to measure 50 mA DC current, press the (B) key, and the multimeter is in the measurement current state.
A, S1 B, S2 C, S3 D, S8
87. Three-phase two-element power meter is often used for the measurement of high-voltage line power, using voltage transformers and (B) to expand the range.
A, voltage transformer B, current transformer C, parallel shunt resistor D, series additional resistor
88. When measuring the pulse signal with an oscilloscope, when measuring the pulse rise time and fall time, it should be defined as the starting and ending reference points from 10% and (D) of the pulse amplitude.
A, 20% B, 30% C, 50% D, 90%
89. When measuring the single-arm bridge, when the galvanometer is zero, the proportional arm resistance value (C) is the ratio of the arm's ratio, which is the resistance of the measured resistance.
A, add B, subtract C, multiply by D, divide by
90. The rotor of the direct current motor is composed of an armature core, an armature winding, and (C) components.
A, base B, main magnetic pole C, commutator D, commutating pole
91. In a single-wave winding of a DC motor, it is required that the two connected components are at a distance of approximately (B) pole pitch.
A, double B, double C, triple D, five times
92. The tachogenerator can be used as a tachometer component. For this purpose, it can be a (A) precision grade DC or AC tachogenerator.
A, any B, higher C, highest D, lowest
93. The tachogenerator can be used as (C)
A, voltage component B, power component C, speed measuring component D, current component
94. Always connect a (C) diode in parallel with the circuit output.
A, rectification B, voltage regulator C, freewheeling D, common
95. In a single-phase bridge full-controlled rectifier circuit, when the control angle a is increased, the average output voltage ud(B).
A, increase B, decrease C, change D, no significant change
96. The triac has a (C) layer structure.
A, 3 B, 4 C, 5 D, 6
97. When using a fast fuse, generally press (B) to select.
A, IN=1.03IF B, IN=1.57IF C, IN=2.57IF D, IN=3IF

98. The cooling pump motor M3 of the X6132 universal milling machine is 0.125KW, and the BB type plastic copper core wire should be selected.
A, 1mm2 B, 1.5mm2 C, 4mm2 D, 10mm2
99. X6132 universal milling machine electrical control board before the insulation resistance is lower than (B), it must be dried.
A, 0.3MΩ B, 0.5MΩ C, 1.5MΩ D, 4.5MΩ
100. Before the X6132 universal milling machine electrical control board is produced, a set of electric tools should be prepared. The drilling tool set includes pistol drill, drill bit and (D).
A, screwdriver B, electrician knife C, bench drill D, tap
101. X6132 Universal Milling Machine When making electrical control board, draw the installation mark, drill, tap, deburr, and grind. Apply anti-rust paint on both sides of the board and spray on the front side (B).
A, black paint B, white paint C, blue paint D, yellow paint
102. When the X6132 universal milling machine line left and right distribution box control boards, pay attention to the control board (A) so that they can freely enter and exit the cabinet after they are installed.
A, size B, color C, thickness D, weight
103. When the X6132 universal milling machine line uses the wire trough to apply for wire laying, (B) should be used.
A, plastic insulated single-core hard copper wire B, plastic insulated soft copper wire C, bare wire D, sheathed wire
104. When the X6132 universal milling machine line wire is connected with the terminal, if there are many wires, the position is narrow, and the wire is not well arranged, then (B)
A, single layer column B, multi-layer column C, horizontal column D, æžž direction
105. X6132 universal milling machine motor installation, generally using lifting device, first lift the motor horizontally to the center height and alignment with the mounting hole, then the motor and (D) connector, align the motor mounting hole, tighten Bolt, and finally remove the lifting device.
A, fastening B, rotating C, bearing D, gear
106. When the electrical connection of the machine tool is connected, the terminal of the component is cut with a wire stripper to cut the appropriate length, strip the terminal, remove the rust, then tin (A), and screw it to the terminal block.
A, set the number sleeve B, measure the length C, organize the thread head D, clean the thread head
Check the electrical integrity of the 107.20/5t overhead crane before installation, including checking the motor, electromagnetic brake, (A) and other control components.
A, wheel controller B, overcurrent relay C, intermediate relay D, time relay
108. 20/5t bridge cranes should be equipped with common instruments before installation, including (D)
A, test pencil B, DC double arm bridge C, DC single arm bridge D, 500V megger
109. 20/5t bridge cranes should be prepared with auxiliary materials, including various specifications of wires required for electrical connection, wire noses of crimped wires, insulating tape, and (D).
A, wire stripper B, needle nose pliers C, electrician knife D, steel wire
110. For the construction of the bridge crane grounding body, a special grounding body or 50 mmx50 mmx5 mm angle steel can be used, and the length is (D), and one end is processed into a pointed shape.
A, 0.5m B, 1m C, 1.5 m D, 2.5 m
111. After the grounding system is completed, the grounding body should be driven vertically into the soil, and at least (B) the grounding body should be driven, and the grounding bodies should be separated by 5m.
A, 2 B, 3 C, 4 D, 5
112. Bridge crane grounding body; all sides of the contact surface during welding shall be welded to (A).
A, increase the welding area B, make the welded part more beautiful C, make the welded part more secure D, make the welding point even
113. When installing the bridge crane grounding body, the grounding body should be buried in (A).
A, soil conductivity is better B, soil conductivity is poor C, soil conductivity is generally D, arbitrary
114. Based on the 20/5t bridge crane guide, adjust the electric conduit and adjust it (A) until the error is ≤ 4mm.
A, horizontal distance B, vertical distance C, tilt distance D, cross distance
115. The power line of the 20/5t bridge crane is available in two ways: (C) and end entry.
A, upper incoming line B, lower incoming line C, intermediate incoming line D, rear incoming line
116. The installation requirements of the 20/5t bridge crane limit switch are: install the fixed limit switch according to the design position. The type and specification of the limit switch should meet the design requirements to ensure safe impact and sensitive action (B). #p#分页头#e#
A, good insulation B, reliable installation C, reasonable use of contacts D, easy to maintain

117. Crane lighting power supply from the 380V power supply voltage through the isolation transformer to obtain 220V and 36V, 36V for (A) lighting and maintenance lighting on the bridge.
A, bridge box control room B, bridge C, electric fan D in the bridge box, electric heating in the bridge box
118. When installing the 20/5t bridge crane wire and pipe, select the wire and tube size according to the wire diameter and the number of the wire, and fix it with clamp, (A) fastening or welding method.
A, screw B, wire C, hard wire D, soft wire
119. The 20/5t bridge crane connecting line must use copper core multi-strand flexible wire. When using multi-strand multi-core wire, the cross-sectional area is not less than (A).
A, 1mm2 B, 1.5 mm C, 2.5 mm D, 6 mm2
120. When wiring the bridge crane control room and control box, after the wires are put on, check the number of wires, (C).
A, quality B, length C, specification D, trend
121. When the bridge crane wires enter the terminal box, the harness is bundled with (B).
A, insulating tape B, wax line C, soft wire D, hard wire
122. The mobile trolley of the 20/5t bridge crane is equipped with main and auxiliary winches, trolley front and rear motion motors and (D).
A, the left and right motion motor B, the lower limit switch C, the disconnect switch D, the rise limit switch
123. Rubber flexible cable supply and feeder lines are installed by streamer. The steel brackets at both ends of the structure are welded with 50 mmx50 mmx5 mm angle steel or channel steel and fixed on the bridge by (A).
A, low foot B, steel tube C, angle steel D, flat iron
124. When the supply and feeder lines are installed by the streamer installation method, the steel cable passes through the bracket hole of the trolley, and the cable is hoisted on the steel cable together with the bearing nylon rope by the lifting ring, and the length of the nylon rope is generally longer than the cable (B )
A, slightly longer B, slightly shorter C, longer 300mm D, length 500mm
125. Winding motor rotor brush short circuit is, when the load starting torque does not exceed 50% of the rated torque, the cross section is selected according to the rated current of the rotor (A).
A, 35% B, 50% C, 60% D, 70%
126. Short-term working system When the working time exceeds (C), the allowable current of wires and cables is determined according to the long-term working system.
A, 1min B, 3min C, 4min D, 8min
127. When the dark place is used in the dry place, the thin wall (B) is generally used.
A, hard plastic tube B, wire tube C, soft plastic tube D, water gas tube
128. When selecting the diameter of the conduit according to the cross-section and number of the conduit, it is generally required that the total cross-section of the conduit should not exceed the cross-section of the conduit (C)
A, 15% B, 30% C, 40% D, 55%
129. According to the principle of wire co-management, (D) shall not be co-managed in the following lines.
A. Power and control loop B with interlocking relationship, signal and control loop of power equipment
C. Different branch lines D of the same lighting method, accident lighting lines
130. The main circuit of the small-capacity transistor governor circuit uses a single-phase bridge type semi-controlled rectifier circuit, which is directly powered by (C) AC power.
A, 24V B, 36V C, 220V D, 380V
131. The voltage negative feedback link in the small-capacity transistor governor circuit consists of R16, (A), and RP6.
A, R3 B, R9 C, R16 D, R20
132. Before commissioning the X6132 universal milling machine, when checking the power supply, first turn on the test power supply and check (A) whether the three-phase voltage is normal.
A, ammeter B, multimeter C, megger D, single arm bridge
133. When the X6132 universal milling machine spindle is started, if the spindle does not rotate, check the motor (A) control circuit.
A, M1 B, M2 C, M3 D, M4
134. When the X6132 universal milling machine spindle brakes, the component operation sequence is: SB1 (or SB2) button action KM1, M1 power loss → KM1 normally closed contact closure → (A) power.
A, YC1 B, YC2 C, YC3 D, YC4
135. In the impulse control of the spindle motor during the X6132 universal milling machine spindle shift, the component operation sequence is: SQA7 action→KM1 moving contact closure closed→motor (A) rotation→SQ7 reset→KM1 power loss→motor M1 stop, The impulse is over.
A, M1 B, M2 C, M3 D, M4

136. When the X6132 universal milling machine spindle is braked on the main shaft. Turn SA2---2 to the ON position; SA2---1 disconnects the 127V control power supply, the spindle brake clutch (A) is energized, and the spindle cannot be started.
A, YC1 B, YC2 C, YC3 D, YC4
137. The X6132 universal milling machine table moves upwards, moving (A) to the “open” position, SA1—1 is closed, SA1—2 is open, and SA1--3 is closed.
A, SA1 B, SA2 C, SA3 D, SA4
138. X6132 universal milling machine table operating handle is on the right (A) stroke switch action, M3 motor forward rotation.
A, SQ1 B, SQ2 C, SQ3 D, SQ5
139. When the X6132 universal milling machine table feeds the shifting impulse, first pull the mushroom handle outward and turn the handle to adjust the turntable to the required feed speed, then pull the mushroom handle to the limit position, then the connecting rod The mechanism is pressed (D) and M3 is turned on.
A, SQ2 B, SQ3 C, SQ4 D, SQ6
140. X6132 universal milling machine table can move quickly to improve work efficiency. When debugging, it must ensure the immediacy and accuracy of YC3 when pressing (D).
A, SB2 B, SB3 C, SB4 D, SB5
141. When the X6132 universal milling machine table is fast feeding and debugging, move the operating handle to the corresponding position and press the button SB5, (B)
When it is powered, its auxiliary contact turns on YC3, and the workbench advances in the selected direction.
A, YM1 B, YM2 C, YM3 D, YM4
142. When commissioning the MGB1420 universal grinding machine, turn the SA1 switch to the “test” position, the intermediate relay KA1 turns on the potentiometer RP6, adjust the potentiometer to make the speed reach (C), and seal the RP6.
A, 20~30r/min B, 100~200r/min C, 200~300r/min D, 300~400r/min
143. When the MGB1420 universal grinder motor is energized and commissioned, turn the SA1 switch to the "on" position, the intermediate relay KA2 is turned on, and connect the speed regulating potentiometer to the circuit, and slowly turn the RP1 knob to make the given voltage signal. (A).
A, gradually increase B, gradually decrease C, first rise and then fall D, first drop and then rise
144. MGB1420 universal grinder current cut-off negative feedback circuit adjustment, workpiece motor power is 0.55KW, rated current is 3A, the cut-off current is adjusted to about 4.2A. Adjust the motor speed to within (D).
A, 20~30r/min B, 100~200r/min C, 200~300r/min D, 700~800r/min
145. When the number of revolutions of the MGB1420 universal grinder motor is stable, V19 and (A) form a positive feedback phase, and R29, R36 and R28 form a voltage negative feedback circuit.
A, R26 B, R27 C, R31 D, R32
146. In the MGB1420 universal grinding machine, when a large-capacity thyristor is triggered, C should be selected to be larger. For example, the thyristor is 50A, and C should be selected (A).
A, 0.47uF B, 0.2uF C, 2uF D, 5uF
147. In the MGB1420 universal grinding machine, the size of the charging resistor R is determined according to the requirements of the phase shift range of the thyristor and (A).
A. The size B of the charging capacitor C, whether the thyristor triggers C, whether the thyristor is turned off after the thyristor is turned on, and whether the thyristor is overheated.
148. In the MGB1420 universal grinding machine, for single-junction transistors, N (A) is generally used.
A, 0.5~0.85 B, 0.85~1 C, 1~2 D, 3~5
Insulation inspection before commissioning of 149.20/5t bridge crane, using 500V megohmmeter measuring equipment (A).
A, insulation resistance B, voltage value C, current value D, electric strength
150. 20/5t bridge crane motor stator circuit debugging, in the case of power failure, pull the cam controller operating handle clockwise, and use the multimeter RX1Ω gear to measure 2L3-W and (A), in the 5th speed Always stay on.
A, 2L1---UB, 2L2---WC, 2L2---UD, 2L3---W
151. When the 20/5t bridge crane zero calibration, set the cam controller to “zero” position. Short the KM coil and measure with a multimeter (B). It should be in the on state when the start button SB is pressed.
A, L1----L2 B, L1----L3 C, L2----L3 D, L3

152. When the 20/5t bridge crane is in the main rise control, put the control handle up (C) to confirm that the KM3 is flexible. Then test R13-R15 should be shorted, thus confirming that KM3 is reliable.
A, first gear B, second gear C, third gear D, fourth gear

153. During the main rise control of the 20/5t bridge crane, when the motor is connected to the line, the control handle is placed in the first gear of the rise, KMup, KM B and KM1 are successively sucked, and the rotor of the motor (D) is higher. When the resistance is running, the main hook should rise at a low speed.
A, M1 B, M2 C, M3 D, M4
154. When the 20/5t bridge crane main structure descends the control line check, set the fourth gear down and observe KMD, KMB, KM1
(A) Reliable pull-in, KMD turns on the main hook motor to lower the power.
A, KM2 B, KM3 C, KM4 D, KM5
155. During the main rise control of the 20/5t bridge crane, the no-load slow-down is reduced, and the brake can be controlled by the brake “2” block and the powerful drop (B).
A, "1" B, "2" C, "3" D, "4"
156. When the 20/5t bridge crane hook is loaded and tested, pay attention to whether there are (C), sound and other abnormal phenomena during the loading process.
A, the current is too large B, the voltage is too high C, the odor D, the no-load loss is large
157. When the feedback strength of the more complicated mechanical equipment is adjusted and the armature current is equal to the rated current (B), the RP3 is adjusted to stop the motor.
A, 1 times B, 1.4 times C, 1.8 times D, 2 times
158. CA6140 lathe three-phase AC power supply is introduced into the terminal block through the power switch, and is respectively connected to the contactor KM1 and the fuse FU1, and is connected to the thermal relay (A) after coming out of the contactor KM1.
A, FR1 B, FR2 C, FR3 D, FR4
159. The power supply of the CA6140 lathe control line is introduced to the fuse FU2 through the transformer (A), and the auxiliary contacts of the thermal relays FR1 and FR2 connected in series are connected to the terminal board No. 6 line.
A, TC B, KM C, KT D, SB
160. In electrical surveying, generally first survey (A), after the survey output.
A, input B, each branch C, a certain circuit D, main line
161. The option to correctly state the relationship between professional ethics and human career is (D)
A. People without professional ethics will not succeed. B. To achieve career success, the prerequisite is to have professional ethics.
C. Successful business people often do not need high professional ethics D. Professional ethics is an important condition for people to succeed in their careers.
162. Regarding occupations and positions, (D) is not required for dedication.
A, establish a professional ideal B, do a line of love, a line of a line of C, comply with the company's rules and regulations D, a job for a lifetime, do not change
163. The correct discussion of innovation is (C).
A, do not stick to the rules, but can not be unconventional B, the company can not afford to toss, bold cockroaches will have problems sooner or later
C, innovation is the driving force of enterprise development D, innovation needs inspiration, but no emotion
164. The role of (C) is to achieve energy transfer and conversion, signal transmission and processing.
A, power supply B, non-electric energy C, circuit D, electric energy
165. The direction of the voltage is specified by (B).
A, the low potential point points to the high potential point B, and the high potential point points to the low potential point
C, low potential points to high potential D, high potential points to low potential
166. The current flowing through each resistor in the series circuit is (B).
A, the sum of the currents B, the equal C, the sum of the currents flowing through the resistors D, the distributed current is proportional to the resistance values
167. The order in which the three-phase electromotive force reaches the maximum is different. The order of reaching the maximum value is called the phase sequence of the three-phase power supply. If the maximum value appears in the order of VUWV, it is called (B).
A, positive sequence B, negative sequence C, order D, phase sequence
168. When ωt=2400, i1, i2 and i3 are respectively (C).
A, O, negative, positive B, O, positive, negative C, negative, positive, OD, negative, O, positive
169.稳压管虽然工作在反向击穿区，但只要（D）不超过允许值，√N结不会过热而损坏。
A、电压B、反向电压C、电流D、反向电流
170.游标卡尺测量前应清理干净，并将两量爪合并，检查游标卡尺的（C）。
A、贴合情况B、松紧情况C、精度情况D、平行情况
171.各种绝缘材料的机械强度的各种指标是（D）等各种强度指标。
A、抗张、抗压、抗弯B、抗剪、抗撕、抗冲击C、抗张，抗压D、含A,B两项
172.（D）是使用最普遍的电气设备之一，一般在70%--95%额定负载下运行时，效率最高，功率因数大。
A、生活照明线路B、变压器C、工厂照明线路D、电动机
173.锉刀很脆，（D）当撬棒或锤子使用。
A、可以B、许可C、能D、不能
174.台钻是一种小型钻床，用来钻直径（C）以下的孔。

A、10mm B、11mm C、 12mm D、13mm
175.手持电动工具使用时的安全电压为（D）.
A、9V B、 12V C、 24V D、36V
176.对于每个职工来说，质量管理的主要内容有岗位的（D）、质量目标、质量保证措施和质量责任等。
A、信息反馈B、质量水平C、质量记录D、质量要求
177.造成直流电动机漏电的主要原因有（A）等。
A、电动机绝缘老化B、并励绕组局部短路C、转轴变形D、电枢不平衡
178.检查波形绕组短路故障时，对于六极电枢，当测量到一根短路线圈的两个线端中间的任何一根的时候，电压表上的读数大约等于（C）。
A、最大值B、正常的一半C、正常的三分之一D、零
179.对于振动负荷或起重用电动机，电刷压力要比一般电动机增加（C）。
A、30%~40% B、40%~50% C、50%~70% D、75%
180.采用热装法安装滚动轴承时，首先将轴承放在油锅里煮，轴承约煮（C）。
A、2min B、 3~5min C、 5~10min D 、15min
181.在无换向器电动机常见故障中，出现了电动机进给有振动现象，这种现象属于（B）。
A、误报警故障B、转子位置检测器故障C、电磁制动故障D、接线故障
182.电磁调速电动机校验和试车时，拖动电动机一般可以全压启动，如果电源容量不足，可采用（C）作减压启动。
A、串电阻B、星一三角C、自藕变压器D、延边三角形
183.交磁电机扩大机装配前检查换向器时，换向器与轴承挡的同轴度允差值应小于0.03mm，在旋转过程中，偏摆应小于（B）。
A、0.03 mm B、0.05 mm C、0.09 mm D、0.12 mm
184.在对称三相电路中，可采用一只单相功率表测量三相无功功率，其实际三相功率应是测量值乘以（B）。
A、2 B、3 C、4 D、5
185.直流双臂电桥适用于测量（B）的电阻。
A、0.1Ω以下B、1Ω以下C、10Ω以下D、100Ω以下
186.直流电动机的转子由电枢铁心、电枢绕组及（C）等部件组成。
A、机座B、主磁极C、换向器D、换向极
187.测速发电机可做校正元件。对于这类用途的测速发电机，可选用直流或异步测速发电机，其精度要求（B）。
A、任意B、比较高C、最高D、最低
188.在单相半波可控整流电路中，ɑ越大，输出Ud（B）。
A、越大B、越小C、不变D、不一定
189.单相桥式全控整流电路的优点是（C），不需要带中间抽头的变压器，且输出电压脉动小。
A、减少了晶闸管的数量B、降低了成本C、提高了变压器的利用率
D、不需要维护
190.由于双向晶闸管需要（A）触发电路，因此使电路大为简化。
A、一个B、两个C、三个D、四个
191.快速熔断器采用（B）熔丝，其熔断时间比普通熔丝短得多。
A、铜质B、银质C、铅质D、锡质
192. X6132型万能铣床制作电气控制板时，划出安装标记后进行钻孔、攻螺纹、去毛刺、修磨，将板两面刷防锈漆，并在正面喷漆（B）。#p#分页标题#e#
A、黑漆B、白漆C、蓝漆D、黄漆
193. X6132型万能铣床线路左、右侧配电箱控制板时，油漆干后，固定好（B）、热继电器、熔断器、变压器、整流电源和端子等。
A、电流继电器B、接触器C、中间继电器D、时间继电器
194.机床的电气连接时，所有接线应（A）。

A、连接可靠，不得松动B、长度合适，不得松动C、整齐，松紧适度D、除锈，可以松动
195.20/5t桥式起重机安装前检查各电器是否良好，其中包括检查（A）、电磁制动器、凸轮控制器及其他控制部件。
A、电动机B、过电流继电器C、中间继电器D、时间继电器
196.接地体制作完成后，应将接地体垂直打入土壤中，至少打入3根接地体，接地体之间相距（A）。
A、5m B、6m C、 8m D、10m
197.桥式起重机接地体安装时，接地体埋设应选在（A）的地方。
A、土壤导电性较好B、土壤导电性较差C、土壤导电性一般D、任意
198.桥式起重机支架悬吊间距约为（B）。
A、0.5 m B、1.5 m C、2.5 m D、5 m
199.起重机照明及信号电路所取得的220V及36V电源均不（C）。
A、重复接地B、接零C、接地D、工作接地
200.桥式起重机操纵室、控制箱内配线时，导线穿好后，应核对导线的数量、（C）。
A、质量B、长度C、规格D、走向
201.桥式起重机电线管进、出口处、线束上应套以（B）保护。
A、铜管B、塑料管C、铁管D、钢管
202.转子电刷不短接，按转子（A）选择截面。
A、额定电流B、额定电压C、功率D、带负载情况
203.短时工作制的停歇时间不足以使导线、电缆冷却到环境温度时，导线、电缆的允许电流按（C）确定。
A、反复短时工作制B、短时工作制C、长期工作制D、反复长时工作制
204.白铁管和电线管径可根据穿管导线的截面和根数选择，如果导线的截面积为2.5mm2，穿导线的根数为三根，则线管规格为（B）mm。
A、13 B、16 C、19 D、25
205.同一照明方式的不同支线可共管敷设，但一根管内的导线数不宜超过（C）。
A、4根B、6根C、8根D、10根
206.小容量晶闸管调速电路要求调速平滑，（B），稳定性好。
A、可靠性高B、抗干扰能力强C、设计合理D、适用性好
207. X6132型万能铣床主轴启动时，将换向开关SA3拨到标示牌所指示的正转或反转位置，再按按钮SB3或（C），主轴旋转的转向要正确。
A、SB1 B、SB2 C、SB4 D、SB5
208. X6132型万能铣床工作台进给变速冲动时，因蘑菇形手柄一到极限位置随即推回原位，所以（D）只是瞬时动作。
A、SQ2 B、 SQ3 C、 SQ4 D、SQ6
209.MGB1420万能磨床电流截止负反馈电路调整时，应将截止电流调至（D）左右。
A、1.5AB、2A C、3A D、4.2A
210. MGB1420万能磨床电动机转数稳定调整时，调节（D）可调节电压微分负反馈，以该善电动机运转时的动态特性。
A、RP1 B、RP2 C、 RP4 D、RP5
211. MGB1420万能磨床中，要求温度补偿较好时可用（B）来确定。
A、经验B、实验方法C、计算D、对比
212.电磁制动器的调整主要包括杠杆、制动瓦、（C）和弹簧等。
A、轴B、动铁心C、制动轮D、静铁心

213.20/5t桥式起重机电动机转子回路测试时，在断电情况下扳动手柄，当转动5个挡时，要求R5、R4、R3、R2、R1各点依次与（A）点短接。
A、R6 B、 R7 C、R8 D、 R9
214. 20/5t桥式起重机的保护功能校验时，短接KM辅助触点和线圈接点，用万用表测量L1~L3应导通，这时手动断开SA1、SQ1、SQFW、（A），L1~L3应断开。
A、 SQBW B、SQAW C、SQHW D、SQDW
215. 20/5t桥式起重机主钩上升控制时，接通电源，合上QS1、QS2使主钩电路的电源接通，合上（A）使控制电源接通。
A、QS3 B、QS4 C、QS5 D、QS6
216.较复杂机械设备电气控制线路调试前，应准备的仪器主要有（C）。
A、钳形电流表B、电压表C、万用表D、调压器
217.较复杂机械设备电气控制线路调试的原则是（D）。
A、先闭环，后开环B、先系统，后部件C、先外环，后内环D、先阻性负载，后电机负载
218.较复杂机械设备反馈强度整定时，使电枢电流等于额定电流的1:4倍时，调节（C）使电动机停下来。
A、RP1 B、 RP2 C、 RP3 D、RP4
219.CA6140型车床是机械加工行业中最为常见的金属切削设备，其机床电源开关在机床（C）。
A、右侧B、正前方C、左前方D、左侧
220.CA6140型车床控制线路的电源是通过变压器TC引入到熔断器FU2，经过串联在一起的热继电器FR1和（B）的辅助触点接到端子板6号线。
A、FR1 B、FR2 C、 FR3 D、FR4
221.电气测绘前，先要了解原线路的控制过程、控制顺序、控制方法和（A）等。
A、布线规律B、工作原理C、元件特点D、工艺
222.电气测绘中，发现接线错误时，首先应（A）。
A、作好记录B、重新接线C、继续测绘D、使故障保持原状

判断题（Ａ表示正确，Ｂ表示不错误）
1.（B）职业道德是指从事一定职业的人们，在长期职业活动中形成的操作技能。
2.（B）职业道德不倡导人们的牟利最大华观念。
3.（B）办事公道是指从业人员在进行职业活动时要做到助人为乐，有求必应。
4.（B）创新即不能墨守成规，也不能标新立导。
5.（B）交流电是指大小和方向随时间作周期变化的电动势。交流电分为正弦交流电和非正弦交流电两大类，应用最普遍的是非正弦交流电。
6.（B）变压器是将一种交流电转换成同频率的另一种直流电的静止设备。
7.（B）启动按钮优先选用绿色按钮：急停按钮应选用红色按钮，停止按钮优先选用红色按钮。
8.（A）维修电工以电气原理图，安装接线图和平面布置图最为重要。
9.（B）普通螺纹的牙形角是55度，英制螺纹的牙形角是60度。
10.（B）用耳塞、耳罩、耳棉等个人防护用品来防止噪音的干扰，在所有场合都是有效的。
11.（A）质量管理是企业经营管理的一个重要内容，是企业的生命线。
12.（B）劳动者患病或负伤，在规定的医疗期内的，用人单位可以解除劳动合同。
13.（A）劳动安全卫生管理制度对未成年工给予了特殊的劳动保护，这其中的未成年工是指年满16周岁未满18周岁的人。
14.（B）从仪表的测量对象上分，电压表可以分为直流电流表和交流电流表。
15.（B）从提高测量准确度的角度来看，测量时仪表的准确度等级越高越好，所以在选择仪表时，可不必考虑经济性，尽量追求仪表的高准确度。\

16.（B）仪表的准确度等级的表示，是仪表在正常条件下时相对误差的百分数。
17.（B）在500V及以下的直流电路中，不允许使用直接接入的电表。
18.（B）X6132型万能铣床的动力电源是三相交流380V，变压器两侧均有熔断器做过载保护。三个电动机还有热继电器做短路和缺相保护。
19.（B）X6132型万能铣床工作台向后、向上压SQ4手柄时，工作台仍不能按选择方向作进给运动。
20.（A）电动机受潮，绝缘电阻下降，可进行烘干处理。
21.（B）在波型绕组的电枢上有短路线圈时，会同时有几个地方发热。电动机的极数越多，发热的地方就越少。
22.（B）安装滚动轴承的方法一般有敲打法、构抓法等。
23.（B）MGB1420型磨床电气故障检修时，如果KM3不能吸合，应检查电源电压、控制电压是否正常，检查热继电器FR1~FR4是否跳开未复位，触点是否有接触不良现象。

24.（B）MGB1420型磨床工件无极变速直流拖动系统故障检修时，锯齿波随控制信号电压改变而均匀改变，其移相范围应在1200左右。
25.（B）晶体管图示仪使用时，被测晶体管接入测试台之前，应先将峰值电压调节旋钮逆时针旋至零位，将基极阶梯信号选择开关跳到最大。
26.（B）X6132型王能铣床所使用导线的绝缘耐压等级为200V。
27.（B）X6132型王能铣床限位开关的安装时，要将限位开关放置在撞块安全撞压去外，固定牢固。
28.（B）X6132型王能铣床控制板安装时，在控制板和控制箱壁之间不允许垫螺母或垫片，以免通电后造成短路事故。
29.（A）机床的电气连接安装完毕后，若正确无误，则将按钮盒安装就位，关上控制箱门，即可准备试车。
30.（A）桥式起重机在室内安装时，室内的接地扁钢沿墙敷设，并安装固定扁钢的卡子。
31.（A）桥式起重机支架安装要求牢固、水平、排列整齐。
32.（A）起重机照明及信号电路电路所取得的电源，严禁利用起重机壳体或轨道作为工作零线。
33.（A）反复短时工作制的周期时间T≤10min，工作时间tg ≤4min时，导线的允许电流有下述情况确定：截面小于10mm2的铝线，其允许电流按长期工作制计算。
34.（A）KCJ1型小容量直流电动机晶闸管调速系统由给定电压环节、运算放大器电压负反馈环节、电流截止负反馈环节组成。
35.（A）当负载电流大于额定电流时，由于电流截止反馈环节的调节作用，晶闸管的导通角减小，输出的直流电压减小，电流也随之减小。
36.（B）20/5t桥式起重机电动机定子回路调试时，反向转动手柄与正向转动手柄，短接情况是完全不同的。
37.（B）机械设备电气控制线路调试前，应将电子器件的插件全部插好，检查设备的绝缘及接地是否良好。
38.（B）CA6140型车床的主轴、冷却、刀架快速移动分别有两台电动机拖动。
39.（B）电气测绘最后绘出的是线路控制原理图。
40.（A）由于测绘判断的需要，一定要由熟练的操作工操作。
41.（B）向企业员工灌输的职业道德太多了，容易使员工产生谨小慎微的观念。
42. ( B )电容两端的电压超前电流900。
43.（B）市场经济时代，勤劳是需要的，而节俭则不宜提倡。
44.（B）电流流过负载时，负载将电能转换成热能。电能转换成热能的过程，叫做电流做的功，简称电功。
45.（A）电解电容有正，负极，使用时正极接高电位，负极接低电位。
46.（B）电气测绘时，一般先输入端，最后测绘各回路。
47.（B）机械设备电气控制线路控制电流测试时，应用万用表测量各点电压是否符合要求。
48.（B）X6132型万能铣床工作台的快速移动是通过点动与连续控制实现的。
49.（A）桥式起重机电源线接线完毕，用万用表检测是否有短路现象，确认完好后，在导管另一端套上封盖端帽。
50.（A）触电的形式是多种多样的，但除了因电弧灼伤及熔融的金属飞溅灼伤外，可达致归纳为三种形式。
51.（B）在电气设备上工作，应填用工作票或按命令执行，其方式有两种。
52.（A）影响人类生活环境的电磁污染源，可分为自然的和人为的两大类。
53.（A）长时间与强噪声接触，人会感到烦躁不安，甚至丧失理智。
54.（B）电子测量的频率范围极宽，其频率低端已进入10-2~10-3HZ量级，而高端已达到4ⅹ106HZ。
55.（B）X6132型万能铣床进给运动时，用于控制工作台向后和向上运动的行程开关是SQ2。
56.（A）X6132型万能铣床工作台变换进给速度时，当蘑菇形手柄向前拉至极端位置且在反向推回之前借孔盘推动行程开关SQ6，瞬间接通接触器KM3，则进给电动机作瞬时转动，使齿轮容易啮合。
57．（B）在MGB1420万能磨床的工件电动机控制回路中，M的启动、点动及停止由主令开关SA1控制中间继电器KA1、KA2来实现，开关SA1有2挡。
58.（A）在MGB1420万能磨床的自动循环工作电路系统中，通过有关电气元件与油路、机械方面的配合实现磨削自动循环工作。
59.（B）在MGB1420万能磨床晶闸管直流调速系统控制回路的基本环节中，V34为功率放大器为移相触发其。
60.（A）在MGB1420万能磨床晶闸管直流调速系统控制回路电源部分，由V9经R20、V30稳压后取得+15V电压，以供给定信号电压和电流截止负反馈等电路使用。
61.（A）安装接线图只表示电气元件的安装位置、实际配线方式等，而不明确表示电路的原理和电气元件的控制关系。
62.（B）用试灯检查电枢绕组对地短路故障时，因实验所用为直流电源，若必须采用高压时，应采用隔离变压器，并且要特别注意安全。
63.（A）确定电动机电刷中性线位置时对小型电机，可在电枢上加上试验电压测量励磁绕组的感应电压。
64.（A）当切削液进入电刷时，会造成直流伺服电动机运转时噪声大。
65.（A）由于各种原因所引起的电动机电源缺相，也会引起电动机不转，可检查原因并将其排除。
66.（B）X6132型万能铣床导线与端子的连接时，敷设完毕，进行修整，然后固定绑扎导线。最后，用小铁锤将线轻轻敲打平整.