CN2073631U - Three phases changeable reactance starter - Google Patents

Abstract

The utility model effectively solves the problem that a three-phase squirrel-cage asynchronous motor has heavy starting current and small starting torque, thus the three-phase squirrel-cage asynchronous motor can frequently start with heavy load, stable speed and speed regulation, and therefore, a winding type asynchronous motor with complicated structure and high cost is replaced. The aim of the utility model is to solve the problem of the distorted waveform of an output power supply. The total reactance of every phase reactor is composed of a plurality of branch reactance units which are connected in series. The utility model having simple structure, convenient manufacture and energy saving can be used for the industries such as mine, metallurgy, shipbuilding, chemical engineering, textile, machine building, etc.

Description

Three phases changeable reactance starter

The utility model belongs to the electrical control equipment manufacturing technology, relates to the starting and the speed governing of three phase squirrel cage induction motor, speed stabilizing control.

Series of advantages such as three phase squirrel cage induction motor has simple in structure, and is with low cost and reliable.But the three phase squirrel cage induction motor across-the-line starting will be subjected to restrictions such as power supply capacity, starting torque will reduce during reduced voltage starting, and use more heavy load decompression starting equipment such as autotransformer starting current and still bigger when reduced voltage starting at present to mechanical impact force, and the starting time is long, motor and starting equipment temperature rise are all very high, cause ageing of insulation and overheated burning out easily.Therefore number of starts will be restricted, and speed governing is also inconvenient, so when manufacturing machine required heavily loaded Fraquent start or requirement to make things convenient for speed governing, three phase squirrel cage induction motor just can not meet the demands.

The purpose of this utility model is that a kind of novel starter three-phase variable reactance starter will be provided, it can solve the big and little problem of starting torque of three phase squirrel cage induction motor starting current effectively, and can Fraquent start and speed governing, high-voltage motor also can be suitable for.Thereby solved the problem of three phase squirrel cage induction motor starting speed governing difficulty, performance can match in excellence or beauty with wire wound asynchronous motor.The utility model also can be applicable in the winding motor rotor circuit, and effect is better than now used starting equipment.

The purpose of this utility model is achieved in that

One. the starting control of three phase squirrel cage induction motor.The key that solves is to have changed motor input power supply wave shape, change into the approximate trapezoid ripple by primary sinusoid, thereby broadening frequency band, improved the electric motor starting power factor, taked simultaneously to prevent the measure of other harmonic wave intrusion again, the power supply wave shape distortion that is input to motor is reduced, thereby under lower voltage, bigger starting torque is arranged still.

The method that solves is: 1. three phase windings of three-phase variable reactance starter are wound on respectively in the three-phase in-line iron core, form the three posts magnetic circuit of opening a way separately, and the reactor phase-splitting is serially connected in A in the threephase stator winding, B, and C three does not disturb mutually.The purpose of doing like this is to prevent other harmonic wave intrusion, influences the out-put supply waveform.Because in closed magnetic circuit, not only have be separated by 120 ° of sine alternating magnetic field of three-phase to exist, also have induced field and induced potential to exist simultaneously.Therefore in the three-phase alternating current cyclomorphosis, can produce the harmonic wave different, make the power supply wave shape distortion that outputs to motor, reduce starting torque with the power supply wave shape phase place.2. reactance coil adopts and to form single coil by single flat type copper wire or flat type aluminium wire lap wound, is assembled in the I font iron core by many single coils orthoscopic of connecting end to end again.Adopt this winding in I font iron core, to form by many N as accompanying drawing 1., the linear magnetic circuit of S. magnetic pole series connection, the magnetic circuit waveform is identical with power supply.Effect is that the little magnetic flux density of out-put supply wave distortion is big, and magnetic hysteresis loss is minimum, and the wide apart distributed capacitance is very little end to end for coil, and inductance value is big.Because the influence of distributed capacitance is the inductance effect of lowering inductor, distributed capacitance is big more, influences big more.Reason be distributed capacitance be just with coil in the inductance parallel connection, form the electric current I 1Q of 180 ° of two phase phasic differences, IC, and these two senses of current are just the opposite, therefore inductance coil and load (motor) series connection in the electric energy part gathered absorb just for capacitor, distributed capacitance is big more, consumption to gather electric energy also big more, thereby reduced inductance value, influenced starting torque simultaneously again.Because the reactance in the reactor starting can not become heat energy, it is 1/4 cycle inner accumulated electric energy when electric current passes through just, this part electric energy next 1/4 the week its in emit the electric current opposite with power supply, thereby the waveform of out-put supply in next 1/4 cycle compensated, broadening frequency band, improved the electric motor starting power factor, increased starting torque, the acceleration motor priming speed.Again because EL=xLI constantly rises electric current E when descending when motor speed _LAlso constantly change decline, output to electric moter voltage and also constantly raise.Therefore electric current changes not quite, and motor speed then constantly quickens to rise.Have automatic Regulation and rising velocity function.Therefore three-phase variable reactance starter efficient is the highest, and starting torque also is maximum.

And present conventional winding is from the beginning around to tail, again by tail around to the end, layering comes and goes winding.Adopt this winding to not influence of direct current, because electric current is constant.But to exchanging is influential, because electric current is an alternation, angular frequency is a ω t amplitude size time to time change.Because ferromagnetic material has hysteresis, the electric current pace of change that is far from is fast, therefore come and go winding, electric current comes and goes with coil and flows, and the magnetic pole that every circle coil produces comes and goes with electric current and changes, beat will appear in magnetic field in the iron core, part magnetic field will be offset, so magnetic hysteresis loss will increase, and inductance reduces, the magnetic circuit wave distortion is serious, and the iron core temperature raises.As adopt closed magnetic circuit, and though magnetic flux flows is speeded up, inductance value increases, the magnetic circuit wave distortion is more serious.The inductance that the produces power effect of can not working can not improve the motor rotational torque, and (but starting torque is more better than resistance can only equally with resistance to play the step-down metering function, meritorious loss is also smaller, because of also there is slicing in resistance, the amplitude limit defective), so starting torque is very low.

Two. the three phase squirrel cage induction motor speed regulating control.The key that solves is that the total reactance with every phase reactor is divided into the branch reactance of some unit to it, and series connection merges and forms then.The purpose of making is after wherein a reactance coil (branch reactance) excises like this, all the other several reactance still exist mutually not to be disturbed, thereby when changing reactance, only need the one section one section ground excision evenly of three-phase variable reactance starter, reactance also reduces with regard to one-level one-level ground, and the voltage and the rotating torque that output to motor are also just increasing.Hinder the alternating current effect because reactance XL has limit, its same unit with resistance also is ohm.Therefore the big more self-induced e.m.f EL of reactance XL is also big more.Because EL and U differ 180 ° but its equal and opposite in direction on phase place, therefore | EL|=|U|=XLI.So the big more reactance output voltage U 2 of XL is just low more, motor speed is just slow more.Method is as long as change the reactance of three-phase variable reactance starter, just can obtain level and smooth speed governing, when for example increasing the speed governing reactance since inertia rotation speed n or revolutional slip s can not change immediately, and along with the reduction of output voltage U 2 and reducing of torque M, torque just descends gradually, electric current I and torque M and can increase are till torque and resistive torque equate.Therefore reactance increases, and revolutional slip s rises, and rotation speed n just descends.Otherwise reactance reduces, and revolutional slip s descends, and rotation speed n just rises, thereby reaches the purpose of speed governing.

Three. the control of three phase squirrel cage induction motor speed stabilizing.Method is to adopt tachogenerator to make feedback signal, controls the break-make of A.C. contactor and bidirectional triode thyristor by control circuit.The contact of A.C. contactor and bidirectional triode thyristor A1, A2 the two poles of the earth respectively are attempted by the two ends of reactance coil.The reactor inductance amount of bidirectional triode thyristor parallel connection should greater than about the inductance value of reactor of two test crosses stream contactor control, purpose is to avoid the A.C. contactor frequent operation.Because of bidirectional triode thyristor is very desirable switch element, it can go to control bigger power output with less signal power, does not have beating and turn-offing electric arc of contact, even single-phase conducting appears in bidirectional triode thyristor, another can not burn out motor to then flowing through from the reactance coil of parallel connection.Use safer.And the bidirectional triode thyristor control circuit is simpler than one-way SCR, as long as the gate pole circuit is switched on or switched off conducting or the shutoff that just can control bidirectional triode thyristor.Therefore can be used as frequent speed stabilizing work.For example controllable silicon conducting one second (time decides according to load and steady speed precision), but rotating speed is still not enough, tachogenerator feedback signal A.C. contactor this moment still on the low side is just closed, and reduce inductance value and come rising speed, on the contrary then higher as rotating speed.The control short circuit shelves number of A.C. contactor can be according to being required to decide by the equipment inertia of transmission and transmission fluctuation, and characteristics are that the capacity motor and the velocity of rotation scope of speed stabilizing is big, can be by less Electric Machine Control to big capacity and high-voltage motor.Rotation speed n controls to rated speed by the number commentaries on classics, and mechanical property hardness is good, and then energy-saving effect is better as adopting power factor compensation.

The utility model great advantage can make the three phase squirrel cage induction motor performance reach the three-phase winding-type asynchronous motor performance.Thereby it is more expensive to eliminate price, and the complex structure maintenance capacity is big, and the three-phase winding-type asynchronous motor that operating cost is high, and simple structure are easily manufactured.Advantages such as it is big to have the little starting torque of starting current, and priming speed is fast, and overload capacity is big, and meritorious loss is little energy-conservation, and the temperature rise of hot weather Fraquent start is extremely low.And applied range can make lifting steady as being applied in elevator or the electric block, be applied in stock-removing machine and can improve working (machining) efficiency and precision, be applied in high-voltage motor and high pressure can be switched to low pressure and control etc., therefore can be widely used in industries such as mine, metallurgy, shipbuilding, weaving, chemical industry, machine manufacturing.

Embodiment:

The utility model is at five tons of bridge-type driving grab bucket JZR ₂-52-8, use in the 30KW winding motor stator circuit, have several angles not rotate when squirrel cage motor uses starting, therefore still keep former normal connecting resistance because of winding motor changes into, the resistance complete removal of actuating section, normal connecting resistance is installed in and is connected in rotor circuit on the dolly.Controller adopts structure light and handy, KTJ6 60/2 cam controller of flexible operation, and make cam into three sections three-phase equilibriums excisions, and modification number is KTX6 60/3, X represents novel, 60/3 expression, 60 A, third gear short circuit.Because what adopt is three sections three-phase variable reactance starters, therefore every phase reactor is made up of three branch reactance.As accompanying drawing 2. zero-bits, reversing phase switch spacing and the change motor rotation direction remains unchanged, and a remaining contact changes does electromagnet power supply, the horizontal installation of cam controller, about each one be fixed on above the three-phase variable reactance starter shielded box, be installed in the driving driver's cabin in.For the ease of installing and shortening connecting conducting wire, controller and starter are installed together.Owing to adopted three-phase variable reactance starter, so winding motor can change the three phase squirrel cage motor into, thereby laborsaving 16 square millimeters of rotor slips of the six roots of sensation alleviate slip weight greatly.Therefore the power unit on the dolly just can design fairly simplely, now adopt 12 millimeters 45# units of φ steel to make the pulley wirerope, adopt 16 square millimeters of the six roots of sensation, three 6 square millimeters BVR copper core plastic cement flexible cords (this line low price, the life-span is very long do open-air mobile slip still using more than 5 years).Make two 30KW motors and two 300 electromagnet power supplies, vehicle motor power supply and spacing lead adopt 8 * 2.5 square millimeters of Plastic-sheathed Cables to supply with, and be sent on the dolly by the truckle car that five grades of sister blocks are formed, structure is lightly ensured smooth transmission, reliable operation is dwindled greatly than former angle iron sliding line volume and weight, and can be because of freezing and angle steel corrosion loose contact, cause and can not move, and can not get an electric shock safely etc.

Owing to adopted three-phase variable reactance starter, therefore protruding controller can directly be controlled once, thereby can omit two huge electromagnetic switch screen and 18 CJ 12B-100A A.C. contactors and huge resistance box groups, make complicated line construction be reduced to very better way circuit greatly, because three-phase variable reactance starter starting torque is big, acceleration is very fast, but the situation that is about 2 times of rated current at the starting transient current within next second just starting under load finish and put into operation, it is very normal that running current is about 50A, because this electric current is directly to reflect starting performance.Since when outage electric current less than the controller rated current, and string has reactance starter again, so power factor is low thereby contact wear is very little, very little.There is the three-phase variable reactor to cushion during again owing to starting, and the voltage that outputs to motor through measurement during the full reactance of the very big input of pressure drop less than 100 volts than rated voltage low 3/4, therefore it is low to sense rotor voltage, also less to the rotor strike electric current, thereby epitrochanterian slip ring walking is smooth and bright like a mirror, and plant equipment is not had impact yet.Because the reactance of three-phase variable reactance starter can not become heat energy, magnetic hysteresis loss is minimum again, thereby temperature rise is extremely low.At the hot weather running hours, skin temperature can be near normal temperature, and the operative employee does not have obvious sensation, adopts three-phase variable reactor starter not only can save a large amount of electric energy from above example proof, save investment, save fortune shape expense, and line construction is simple, easy to maintenance, the traffic space position is big, cleaning is convenient, and is in light weight, safe and reliable etc.

The concrete structure of utility model is provided by following examples and accompanying drawing.Fig. 1 only divides the reactance profile according to the three-phase variable reactor list that the utility model proposes, describes the details of the concrete device that the present invention proposes and the working condition of Fig. 2 in detail below in conjunction with Fig. 1.This device comprises iron core (1).Core structure adopts the I font, core material can be selected for use according to volume and purposes, be used for speed governing or want cube little can select the high silicon steel sheet of the less silicon content of loss for use, be used to start optional inferior silicon steel sheet, solenoid (2) selects for use flat copper electromagnetic wire lap wound in graded insulation wire frame (3), and the width of wire frame and flat type copper wire is suitable, should soak insulating varnish after coiling is intact, (4) lead-out wire line nose, (5) fixed support.Figure (2) is a three-phase variable reactor electrical schematic diagram.It is to adopt the third gear short circuit according to the drive apparatus requirement, and three branch reactance XL are adopted in therefore every total mutually reactance ₁, XL ₂, XL ₃Series connection merges composition end to end, and is controlled by a shelves short circuit by cam controller contact 2JKT 3JKT 5JKT.JKT is cam controller control power supply X ₁X ₂With the reversing phase switch contact, the right JKT and JKT ₂Be up first gear switch of control electromagnet JT and second grade of cam controller switch contact of following behavior, motor D can adopt reuses YZ series squirrel cage motor.That now adopt is original motor JZR ₂Winding motor, but the rotor loop string has fixing normal connecting resistance.

Claims (3)

1, three phase squirrel cage induction motor starting, three-phase variable reactance starter (branch reactance) device of speed governing and speed stabilizing control, this device have iron stamen (1) and solenoid (2) to form, and it is characterized in that: iron stamen (1) adopts I font structure.Solenoid (2) adopts the flat electromagnetic wire lap wound, and segmentation is wound in the insulation wire frame (3), and every total mutually reactance is connected end to end to merge by several branch reactance and formed.

2, according to the described device of claim 1, it is characterized in that smooth rate apparatus makes feedback signal by tachogenerator, A.C. contactor and bidirectional triode thyristor are done the control and the frequent control of speed stabilizing.

3,, it is characterized in that speed governing and starting device are by the control of KTX6 series cam controller according to the described device of claim 1.

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