CN2185006Y

CN2185006Y - Stepless speed regulating induction asynchronous motor

Info

Publication number: CN2185006Y
Application number: CN 93224473
Authority: CN
Inventors: 孙国华
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-01
Filing date: 1993-08-30
Publication date: 1994-12-07
Anticipated expiration: 2003-08-30

Abstract

The utility model relates to a stepless speed regulating induction (asynchronous) motor. The utility model is characterized in that a set of movable stator cores and windings thereof are additionally arranged in a base of a common induction (asynchronous) motor, a regulating mechanism which is composed of a feed screw nut and a lever is used for regulating the phase between two sets of stator cores to realize stepless speed regulation. The utility model is suitable for being used on loads of which the torque (power) is reduced with the drop of rotary speed, such as blowers, water pumps, etc.

Description

Stepless speed regulating induction asynchronous motor

Utility model relates to a kind of stepless speed regulation induction motor.

Induction motor, particularly cage induction motor have advantages such as simple in structure, reliable, easy to maintenance, cheap, but its starting, speed adjusting performance poor (" electrotechnics " first volume, Qin Cenghuang, Higher Education Publishing House).Though frequency conversion, variable voltage control can improve the speed governing of induction motor, variable frequency power supply, voltage regulator complex structure, cost height, and it is unreliable to work, and has harmonic wave to cause motor seriously to generate heat, and must strengthen cooling, has increased the volume of motor, weight; Though wound-rotor induction motor can be in rotor loop serial-resistance speed-regulation, but efficient is low, then governing system complexity, cost height when adopting tandem control, and it is unreliable to work, also there is Harmonic Interference to transfer net (" automatic control system " Chen Baishi chief editor, China Machine Press's in July, 1981 version).

The purpose of utility model is, changes the structure of existing induction motor, makes it under the situation that does not need complicated speed regulating device, realizes stepless speed regulation, improves starting performance, and keeps advantages such as induction machine is simple in structure, reliable, with low cost.

Utility model mainly comprises three parts such as stator, rotor and governor motion.(seeing accompanying drawing 1)

Stator comprises support, end cap, stator core, stator winding.Stator core and stator winding all are two covers, and movable stator core 2 and winding 3 thereof, fixed stator unshakable in one's determination 4 and winding 5 thereof when feeding alternating current, produce two with fast rotating magnetic fields in the same way, and the phase place between two rotating magnetic fields can change by governor motion.

By dynamics formula

T _m－T _fz＝I (dω)/(dt) （1）

As can be known, as load torque T _FzWhen constant, change driving torque T _mJust can change rotating speed.For motor driving system, T _mBe exactly the electromagnetic torque of motor, and T _mMeet the represented relation of following formula again

T _m＝－ (π)/2 P ²φFrSinδr （2）

Wherein P is the magnetic pole logarithm of motor, and φ is the air gap resultant flux, and Fr is a rotor magnetic potential, and δ r is the angle between Fr and the φ.Because

φocFr＋Fs （3）

So, change Fr and just can change torque Tm, and Fr is rotor current Ir generation, and the Ir electromotive force E that to be rotating magnetic field induce in rotor loop ₂Produce, present two rotating magnetic fields induce electromotive force E respectively in the stator loop ₂₁, E ₂₂(seeing accompanying drawing 3), then

E ₂＝E ₂₁＋E ₂₂（4）

If two cover stator core windings are identical, then

E ₂＝2E ₂₁COS (α)/2 ＝2E ₂₂COS (α)/2 （5）

So infinitely regulate two phase places between rotating magnetic field, just can change torque Fm, thus infinitely speed governing.

Governor motion is used for regulating the phase place between two stator fields, and it comprises that leading screw 8 nuts 6 and an end have the lever 7 of fork.The bearing pin vertical with leading screw arranged on the nut, the fork of lever cooperates with bearing pin again, its other end (seeing accompanying drawing 3) rotational lead screw that links to each other with movable core 2, and nut is along the leading screw rotational, rotate around electrical axis by the movable stator core of lever actuated, thereby regulate two phase places between magnetic field.

During electric motor starting, two cover winding correspondences are in series, just can reduce the operating voltage of every cover winding, reach the purpose of reduced voltage starting.Two correspondences of overlapping windings are in parallel after the starting, starting circuit can realize (seeing accompanying drawing 4) by contactor again.

Utility model has been compared following advantage with common induction machine:

1, starting is convenient, and equipment is simple: do not need voltage regulator during reduced voltage starting, only need contactor, reduced the volume of power distribution cabinet, weight and cost;

2, can realize stepless speed regulation and saves energy easily;

3, there is not the Harmonic Interference electrical network during machine operation.

In conjunction with concrete accompanying drawing, the utility model is further specified now.

Fig. 1: stepless adjustment speed induction (asynchronous) motor: 1-stator seat and end cap, the movable stator core of 2-, the winding in the movable stator core of 3-, the 4-fixed iron core, the winding on the 5-fixed stator iron core, the nut of 6-band bearing pin, the lever of 7-band fork, the 8-screw mandrel.

Fig. 2: K-K cutaway view of the present utility model.

Fig. 3: two induced potential E that rotating magnetic field produces in rotor loop respectively ₂₁, E ₂₂With synthetic electromotive force E ₂Between phasor diagram.

Fig. 4: starting circuit schematic diagram.CJ during starting ₂₁, connect CJ ₂₃, CJ ₂₁Disconnect CJ ₂₂Connect.Starting back CJ ₂₃, CJ ₂₁Connect CJ ₂₂Disconnect.

Claims

1, the stepless speed regulation induction motor mainly comprises stator, and rotor and governor motion three parts is characterized in that:

Stator core and stator winding all are two covers, and wherein a cover stator core and winding thereof can rotate around electrical axis; Governor motion is made up of the lever that a cover leading screw nut and an end have fork, bearing pin with the leading screw axis normal is arranged on the nut, the fork of one end of lever matches with bearing pin again, the other end connects firmly with movable stator core, rotational lead screw just can be regulated the phase place between two cover stator cores, thereby changes the rotating speed of motor.

According to the described motor of claim, it is characterized in that 2, the correspondence of two cover windings is in series during reduced voltage starting.