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- 2. reluctance motor – реактивный индукторный двигатель Permanent Magnet Synchronous Motor (PMSM) – вентильный двигатель Brushless Direct
- 3. MOTOR CLASSIFICATION An electric motor is a device which converts electrical energy into kinetic energy (i.e.
- 5. The direct current motor or the DC motor has a lot of application in today’s field
- 6. Types of DC motors
- 7. DC motors are often used in applications where precise speed control is required. They are divided
- 8. OPERATING PRINCIPLES a) Major Parts All motors have two basic parts: • The STATOR (stationary part)
- 12. Motor’s Electrical Equations The elevator is driven by a permanent-magnet DC motor. The equivalent circuit of
- 13. The motor voltage equation of the armature circuit is: where: is the electro-motive force developed in
- 14. Mechanical System’s Motion Equations The motion equation of the entire system from the motor’s perspective is:
- 15. The load torque that is placed on the drive pulley which is mounted on the motor’s
- 16. Eqn. 1 was derived for the elevator mechanical system in which the force exerted by the
- 17. This power when written with respect to the pulling belt is: Replacing the belt speed with
- 18. Eqn. 4 and Eqn. 5 hold only when the car is moving upwards and the belt
- 19. Substituting the load torque equation for when the elevator car is moving upwards (Eqn. 6) into
- 20. DC motor modeling
- 21. DC motors DC motors possess characteristics that make them attractive for certain applications. For example, very
- 22. Current flows through the armature windings via carbon brushes and a commutator assembly. The commutator assembly
- 23. This causes the armature to appear as a magnet with which the stator field interacts. The
- 24. Series motor – steady-state operating characteristics The series connection of armature and Weld windings means that
- 25. Reversing the direction of the applied voltage (and hence current) therefore leaves the direction of torque
- 26. It is important to note that under normal running conditions the volt drop across the series
- 27. Returning to Figure (b), we note that the series motor differs from most other motors in
- 28. Large series motors have traditionally been used for traction. Often, books say this is because the
- 29. The inherent suitability of the series motor for traction is illustrated by the curves in Figure,
- 30. Some form of speed control is obviously necessary in the example above if the speed of
- 31. This method is inefficient because power is wasted in the resistors, but is simple and cheap
- 32. Four-quadrant operation and regenerative braking The beauty of the separately excited d.c. motor is the ease
- 33. An armature voltage controlled d.c. machine is therefore inherently capable of what is known as ‘four-quadrant’
- 34. Secondly, the supply voltage is shown by the old-fashioned battery symbol, as use of the more
- 35. If, with the motor running at position A, we suddenly reduce the supply voltage to a
- 36. Needless to say the motor will not remain at point B if left to its own
- 37. If we want to operate continuously at position B, the machine will have to be driven
- 38. Separately Excited DC Motor The field (or stator) coil contains a relatively large number of turns
- 39. Excellent speed regulation is characteristic of this design which lends itself well to speed control by
- 40. Compound DC Motor The compound DC motor uses both series and shunt field windings, which are
- 41. Permanent Magnet DC Motors These motors use permanent magnets in place of field windings to establish
- 42. Permanent magnet motors are often used in low horsepower applications, particularly those that are battery operated
- 43. The equations to model the system are:
- 44. Brushed DC Motor In this type of motors, magnetic field is produced by passing current through
- 45. Electronically Commutated Motor (ECM) An ECM is an electronically commutated permanent magnet DC motor (Figure). Electronics
- 46. Although presently more costly than alternative motor technologies, the higher efficiency and flexible operating characteristics of
- 47. Thyristor d.c. drives – general For motors up to a few kilowatts the armature converter can
- 48. The arrangement shown in Figure is typical of the majority of d.c. drives and provides for
- 49. Low power control circuits are used to monitor the principal variables of interest (usually motor current
- 50. DC motor, a view inside Simple, cheap. - Easy to control. - 1W - 1kW -
- 51. DC motor control Controller + H-bridge (allows motor to be driven in both directions). Pulse Width
- 52. Speed Control of DC Motors: the speed of a motor is given by the relation It
- 53. Speed Control of Shunt motor: 1. Variation of Flux or Flux Control Method: By decreasing the
- 54. 2. Armature or Rheostatic Control Method: This method is used when speeds below the no-load speed
- 55. Voltage Control Method: (a) Multiple Voltage Control: In this method, the shunt field of the motor
- 56. Speed Control of Series Motors: 1. Flux Control Method: Variations in the flux of a series
- 57. (b) Armature Diverter: A diverter across the armature can be used for giving speeds lower than
- 58. (c) Trapped Field Control Field: This method is often used in electric traction. The number of
- 59. (d) Paralleling Field coils: this method used for fan motors, several speeds can be obtained by
- 60. 2. Variable Resistance in Series with Motor: By increasing the resistance in series with the armature
- 61. Electric Braking: A motor and its load may be brought to rest quickly by using either
- 62. Electric Braking of Shunt Motors: (a) Rheostatic or Dynamic Braking: In this method, the armature of
- 63. (b) Plugging or Reverse Current Braking: This method is commonly used in controlling elevators, rolling mills,
- 64. (c) Regenerative Braking: This method is used when the load on the motor has over-hauling characteristic
- 65. Electric Braking of Series Motor: (a) Rheostatic (or dynamic) Braking: The motor is disconnected from the
- 66. (b) Plugging or Reverse Current Braking: As in the case of shunt motors, in this case
- 67. (c) Regenerative Braking: This type of braking of a series motor is not possible without modification
- 68. Servo motors Although there is no sharp dividing line between servo motors and ordinary motors, the
- 69. The even more arduous condition in which the full armature voltage is suddenly reversed with the
- 70. In the ironless rotor or moving-coil type (Figure 2.14) the armature conductors are formed as a
- 71. Needless to say the absence of slots to support the armature winding results in a relatively
- 72. Early versions were made by using printed-circuit techniques, but pressed fabrication is now more common. Since
- 73. DC servo drives The precise meaning of the term ‘servo’ in the context of motors and
- 74. Motors were therefore developed to meet these exacting requirements, and not surprisingly they were, and still
- 75. The majority of servo drives are sold in modular form, consisting of a high-performance permanent magnet
- 76. Position control As mentioned earlier many servo motors are used in closed-loop position control applications, so
- 77. In the example shown in Figure, the angular position of the output shaft is intended to
- 78. The feedback voltage (representing the actual angle of the shaft) is subtracted from the reference voltage
- 79. The dynamic performance of the simple scheme described above is very unsatisfactory as it stands. In
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