Тестовые задания

Test tasks

1. Uneven production of slip rings eliminate:
A) turning on a lathe
B) polishing a glass skin
B) replacement of slip rings
G) replacement shaft

2. The weakening of the compact core causes:
A) the specific noise
B) stop of the electric machine
B) the buzz of the electric machine
G) damage to the core

3. Jumpers in the terminal box when connecting the stator winding:

A) star (a) triangle (b)
B) triangle (a) star (b)
B) a star with the derived neutral(a) triangle (b)
G) a triangle (a), a star with ungrounded neutral(b)

4. The magnetic field generated by the winding of three-phase motor is:
A) a rotating
B) constant in magnitude
C) pulsating in time
D) oscillatory

5. The condition of the winding insulation of the repaired electrical machine check:
A) ammeter
B) megger
B) a wattmeter
D) an ohmmeter
6. Violation of milostowo insulation eliminate:
A) impregnation with a varnish, laying plates of mica
B) alignment of the mold plates
B) a filler of fiberglass
G) replacement plate

7). The motor does not develop rated speed and buzzing:
A) misalignment of bearing shields or shaft bending
B) phase of the stator winding
B) winding short circuit in the stator winding
D) bearing failure

8. Repair damaged Seating surfaces of the shaft produces:
A) elektronaladka metal
B) a drilling shaft
B) cutting down seats
G) polishing the shaft

9. Damage of rolling bearings is expressed by:
A) wear tracks
B) in the Shine bearings
B) dullness bearings
G) to stop electric cars

10. Significant local heating of the stator winding is called:
A) the violation of the insulation of the winding
B) symmetry breaking of the winding or line voltage
In) winding contamination
G) breakage of the winding

11. Cause excessive heating of bearings is:
A) incorrect operation of motor
B) wrong Assembly of the bearings, contamination of the bearings
C) overload of electrical machine
G) improper installation of the electric machine on the Foundation

12. Banding of the rotor of the motor is produced:
A) for isolation grooves
B) to test the windings
B) to hold the windings in the slots
G) winding insulation

13. Types of balancing:
A) static, electric
2) static, mechanical
3) static, dynamic
4) electrical, mechanical

14. n 2 -:
A) the frequency of rotation of the rotor
B) slide
B) speed of stator magnetic field
G) the angular frequency

15. Type of damage "breach of contact and the destruction of joints":
A) mechanical
B) electric
B) galvanic
D) moral

16. Engine supply slip rings and brushes:
A) to connect the motor to the network
B) for the connection of the rotor with an adjusting rheostat
B) it depends on the type of engine
G) for the transmission of electric current

17. The rotor is not rotating or rotating slowly, the engine drone and strongly heated:
A) phase winding of the stator
B) short circuit in the stator winding of the electric motor
B) unilateral gravity of the rotor
G) fluffing up extreme electrical steel sheets

18. Disassembly asynchronous electric machines usually start:
A) to remove the bearings
B) by removing bearing shields
C) remove the coupling half
G) removal of the terminal box

19. Damage to electric motors of alternating current are:
A) the presence of clearances between rotating and stationary parts of the electric machine
B) deformation of the rotor shaft
B) the circuit between turns in the winding
G) heating the bearings

20. Name of the operation current repairs of electric motors:
A) cleaning exterior surfaces of the machine
B) removing the old windings
C) grinding of contact rings
G) repair of core plates

21. The circuit of the windings on the motor casing can be found:
A) the ohmmeter
B) ammeter
B) voltmeter
D) megger

21. Electric motors have a maximum permissible excess temperature:
A) from 50 to 135°C
B) from 40 to 90°C
B) from 60 to 135°C
D) from 60 to 125°C

22. The actuator includes:
A) one motor
B) multiple motors
B) as many motors, when does this type of actuator
G) two motor

23. Asynchronous motor with slip-ring rotor supply slip rings and brushes:
A) for connection of the rotor with an adjusting rheostat
B) for connecting the stator with the adjusting rheostat
In) for connecting the motor to the mains
G) to connect the engine

24. Contaminated surface breaking contacts clean:
A) emery cloth
B) needle files
B) mounting a knife
D) screwdriver

25. To check the mechanical part of the magnetic actuator comprises:
A) check the condition of bolted connections
B) check condition of insulation coil
B) check for wear of the bushings, axles, springs
G) check condition of insulation of the magnetic circuit

26. Operation related to repair of circuit breakers:
A) repair the windings
B) repair of magnetic core
B) the repair of the contact surfaces of knives and sponges
G) repair of magnetic parts

27. With the weakening of the spring blades and contact jaws of the circuit breakers need:
A) tighten all fasteners
B) blades to replace with new
B) the springs replaced with new
G) replace the switch

28. Insufficient pressing of the contacts in the magnetic actuators can lead:
A) to overheating and burning of contacts
B) for buzz contacts
B) to vibration contacts
G) to increase wear resistance

29. Basically the operation of electrical apparatus is:
A) to verify the absence of soot and grime contacts
B) to check the tripping contacts, electromagnets and mechanisms
B) to verify the absence of heating
G) to check the presence of traces of oxide

30. During Assembly of the motor after repair check the air gap:
A) between the stator and the bearing
B) between the rotor and the bearing
In) between the stator and the rotor
D) between the bearing and the fan

31. Mechanical damage to the magnetic actuator can be identified:
A) visual inspection
B) megger
B) electrical tests
G) mechanical test

32. Oxide film of the contact surfaces:
1) improves contact
2) degrades the contact
3) does not affect the contact
4) reduces the contact resistance

33. Conditional graphic designation in the wiring diagram the contacts of the thermal relay:
A) B) C) D)


34. Fuse burns out:

A) in case of overload
B) when heated
B) in case of short circuit
G) under cooling

35. The contacts of the magnetic starters provide cermet-tipped:
A) to increase the duration of their work
B) for better electrical contact
V) to exert
G) to protect from vibration

36. The magnetic circuit of the transformer type from single sheets of electrical steel:
A) easier to collect
B) you can change the cross section of the magnetic circuit, changing the number plates
B) to reduce the losses on eddy currents

37. Put the fuses in the primary winding of the transformer:
A) if the failure prevents the primary winding
B) in case of failure of the protecting secondary winding
B) if the failure prevents the primary and secondary windings

38. The magnetic circuit of the transformer is made of:
A) copper
B) cast iron
In) of steel
D) iron


39. The voltage at the terminals of the secondary winding to exceed:
A) EMF of the primary winding
B) the EMF of the secondary winding

1) can
2) A) can't; B) may
3) A) can; B) may not

40. The ratio is called
A) the ratio of the numbers of turns of the transformer windings
B) the ratio of useful power transformer for power consumed them from the network source of electrical energy

41. Terminals attached to the mains if the step-down transformer
A) A, B, C
B) a, b, C
C) 0, a, b, C

42. The principal difference from the autotransformer transformer
A) low ratio
B) the possibility of changing the transformation ratio
B) electrical connection of primary and secondary windings

43. Parallel operation of transformers is permitted under the following conditions
A) groups of connections of windings are the same; the ratio of transformers capacities of at least 1:3; the coefficients of transformation differ by no more than ± 0.5%; voltage short circuit differ by no more than ± 10%; produced phasing transformers
B) groups of connections of windings are the same; the ratio of transformers capacities of at least 1:3; the coefficients of transformation differ by no more than ± 1,5%;
C) the coefficients of transformation differ by no more than ± 0.5%; voltage short circuit differ by no more than ± 15%; produced by the phasing transformers

44. For oil transformers allowed continuous load of one or two windings of the current
A) exceed 15 % of the rated current of the branch, if the voltage of any one of the windings does not exceed the rated voltage of the corresponding branch
B) greater than 5% of the rated current of the branch, if the voltage of any one of the windings does not exceed the rated voltage of the corresponding branch
B) exceeding 10% of the rated current of the branch, if the voltage of any one of the windings does not exceed the rated voltage of the corresponding branches.

45. Transformers used to supply electricity to residential premises
A) power
B) measuring
B) special

46. The operating principle of a transformer is based
A) the law of ampere
B) law of electromagnetic induction
C) Lenz's law

47. Magnetic circuit three phase transformer must have
A) one
B) two
B) three

48. The transformation ratio
A) f = 1/T
B) k = w1/w2
B) n2 = n1 – ns

49. There are the following methods of drying transformer cores
A) mechanical, electrical, chemical
B) electrical, chemical
B) method of induction loss in the steel of the tank in a special Cabinet, infrared rays, electric blower, short-circuit current, in a vacuum

50. When testing transformer oil are
A) the presence of mechanical impurities; the content of acids and alkalis; water content, electric strength oil
B) the correctness of joining of the windings to the terminals; a particulate coal; the color of the oil

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