The application of AC motor commutator?
2015-12-07 15:17:34 admin 18
Its speed range is wide, the ratio of the highest speed and lowest speed is 3:1, 6:1, 10:1. It also has the function to adjust the power factor, so that the highest rated speed of full load power factor, in the absence of compensation can also reach about 0.98. Compared with the general cage type three-phase asynchronous motor, three-phase AC commutator motor starting current is small, compared to the starting torque is big, but the full load efficiency is slightly lower; and an electromagnetic speed regulating asynchronous motor. It can not only speed under no load and speed range larger, its can index and thyristor motor is similar. So, three-phase AC commutator motor applicable requirements in a wide range of uniform speed of electric drive in the textile, paper, sugar, rubber and other fields.
Three-phase commutator motor with three-phase shunt commutator motor and three-phase commutator motor series two. The air gap magnetic field produced symmetrical three-phase motor commutator commutator winding AC EMF is circular rotating magnetic field. If rotation of the average flux density? L to speed 's rotation, and commutator winding to rotary', commutator winding conductor will to relative speed ('-') cutting magnetic field generation of electromotive force. The effective value is proportional to the relative speed. However commutator winding conductor while moving at the speed ', but static brush, it connected part of the winding in space is always in a certain location, so by the brush cited connecting branches can be seen as stationary in space. According to the magnetic field of branch cutting per minute of pole pairs is the principle of the frequency of the electromotive force and frequency of branch electric potential by the magnetic field of static brush speed 's decision.
Three phase shunt commutator motor with two windings in the rotor with the commutator. A is derived from the slip ring and brush a three-phase AC winding 3, it is fed by a three-phase AC power grid, as the original edge; another is drawn by the brushes on the commutator commutator winding 2, it through the brush a1-a2, B1-B2, C1-C2 and the stator winding a, B and C are connected in series to form a closed loop, constitutes a motor side. A1-a2, B1-B2 and C1-C2 of the open angle of the 2 beta are adjustable. Three on the brush can also move along the circumference to the desired location.
Three-phase AC commutator motor with slip ring of the rotor winding through the three-phase alternating current motor air gap magnetic field it relative to the rotor to synchronous speed 's rotation. If the rotor to rotate speed are reverse rotation, the magnetic field with respect to each branch of the stator and commutator winding speed to the slip speed ('-'), thus in the stator windings and the commutator winding sense electromotive force for slip frequency. It is with slip (see asynchronous motor) changes. However, the magnetic field of rotor with fixed relative velocity (synchronous speed 's), so the size of the commutator winding EMF and slip. Three phase shunt commutator motor rather practical in the secondary windings (i.e. the stator (a, B, C winding) string into the slip frequency electric motive force (i.e. commutator winding of electric potential) of asynchronous motor. The difference lies in that the former is placed on the rotor, and the side of the side is placed on the stator.
The speed of the motor is realized by the adjustment of the 2 - P of the brush opening angle. Power factor adjustment depends on the change of the relative position of the three stator windings with the same time shift three. If the brush opening angle of 2 - to zero, the side of the electric potential is equal to zero, at this point, it is the same as the general three-phase asynchronous motor. When a 2 day non zero angle beta, in the side of adding additional electromotive force. The addition of electric potential, the total electric potential and electric current of the secondary circuit are changed. To maintain the electromagnetic torque is the same original value, it is necessary to change the motor slip, to change the stator electromotive force, so that the secondary side current is basically restore the original value. This means that the speed is changed. If the electric potential is in the phase of the stator, the electric potential is increased by the adjustment of the brush position. If the brush into the commutator EMF and stator electromotive force anti phase, the speed drop.
This motor speed control performance is very good, not only can be down, but also to the up, to make it more than the synchronous speed. Speed range of general up to 10:1. Move the brush in the circumferential direction, the commutator EMF and stator electromotive force with different phase difference, can regulate the operation of the power factor. This is due to the commutator electromotive force series, and changing phase of the electromotive force and current, reflected to the primary side of the performance of the power factor of the change. It should be noted that the direction of the movement of the brush is higher than the synchronous speed and lower than the synchronous speed.
Three phase series commutator motor stator windings A, B, C, B, C and a through the brush and the commutator windings are connected in series. Figure in the winding commutator winding is equivalent to Y connection method. Brush a, B, C can move at the same time, to change the angle of the.
The series three-phase commutator motor and three phase shunt commutator motor difference is: the stator windings and the commutator winding adopts the series connection; rotor only a commutator winding and without slip ring AC winding; AC power supply is applied to the stator windings of a, B and C endpoint and not on the rotor. When the motor is energized, the stator and rotor windings are produced by a rotating magnetic flux. If the angle between the stator and the rotor winding is a, the stator flux potential F1 and the rotor flux potential F2 are also different in space. The principle of generating torque of two vertical magnetic field. Any one of the magnetic flux potential.