CN205249113U - Tower machine amplitude changing device variable frequency speed control system - Google Patents
Tower machine amplitude changing device variable frequency speed control system Download PDFInfo
- Publication number
- CN205249113U CN205249113U CN201521103032.0U CN201521103032U CN205249113U CN 205249113 U CN205249113 U CN 205249113U CN 201521103032 U CN201521103032 U CN 201521103032U CN 205249113 U CN205249113 U CN 205249113U
- Authority
- CN
- China
- Prior art keywords
- speed
- frequency
- frequency converter
- tower machine
- converter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Control Of Ac Motors In General (AREA)
Abstract
The utility model discloses a tower machine amplitude changing device variable frequency speed control system, including linkage table, limit signal collection system, PLC controller and converter, wherein: limit signal collection system, converter link to each other with the PLC controller respectively, the converter is connected with linkage table and amplitude changing device's change width of cloth motor respectively, linkage table, converter, amplitude changing device's change width of cloth motor, speed reducer and cylinder constitute one in the same direction as the accuse return circuit. Compared with the prior art, the utility model has the advantages that: adopt the current control stepless speed control mode, make tower machine amplitude changing device the driver controls under, can be smoothly rise maximum speed steadily from the zero -speed, put in order also the samely from maximum speed to zero speed adjusting, just so improved quick -witted complete machine work efficiency and the job stabilization nature of tower.
Description
Technical field
The utility model relates to a kind of tower machine jib lubbing mechanism frequency-converting speed-governing control system.
Background technology
At present, the jib lubbing mechanism of derrick crane is to carry for tower machine hangs a year behavior change operating radius (luffing)For the transmission device of horizontal motion-promotion force, this device is mainly by motor, reduction box, reel and luffing controlThe formations such as system processed, because tower machine luffing scope large (0-50/60 rice conventionally), the speed of service are fast, at luffingThe impulse ratio in process, lift heavy being produced is larger; With regard to the speed regulating control technology of tower machine jib lubbing mechanism, luffingMechanism adopts auto-transformer stepping to drive double speed or three-speed motor to realize jib lubbing mechanism speed governing, these tune moreSpeed mode all can not realize stepless speed control, and larger to transmission mechanism impact, because above-mentioned mode of speed regulation belongs to completePower speed control, can cause that equipment operation energy consumption is large, reliability reduces, fault rate raises, maintenance cost increases,The problem such as difficult in maintenance. In order to overcome these problems, in prior art, also there is the more advanced frequency control of employingTechnology, but its luffing electric machine speed regulation adopts gear control mode more, and set position frequency, adopts gear to giveFixed frequency realizes the effect of step frequency conversion, and between gear, speed is ladder, cannot realize luffing motorSmooth stepless speed-regulating.
Utility model content
The utility model has overcome shortcoming of the prior art, and the frequency control of a kind of tower machine jib lubbing mechanism is providedControl system, adopts Current Control stepless speed regulation mode, makes tower machine jib lubbing mechanism under driver's manipulation, canStably be raised to maximum speed from zero-speed smoothly, also identical to zero-speed adjustment from maximum speed, so just carryHigh complete machine operating efficiency and the job stability of tower machine.
The technical solution of the utility model is: a kind of tower machine jib lubbing mechanism frequency-converting speed-governing control system, comprises connectionMoving platform, limit signal harvester, PLC controller and frequency converter; Wherein: described limit signal collection dressPut, frequency converter is connected with PLC controller respectively, described frequency converter respectively with the change of joint action table and jib lubbing mechanismWidth motor connects, and luffing motor, reductor and the cylinder of described joint action table, frequency converter, jib lubbing mechanism formA sequence loop.
Further, described joint action table is also provided with electric current speed adjusting module, for by the handle position of joint action tableInformation is converted to the current signal of 4-20mA, enters frequency converter, frequency conversion by frequency converter analog input endDevice coding is the different frequency between corresponding output 0-50Hz respectively.
Further, between PLC controller and frequency converter, there is low speed by low speed resistance loop switch in parallelResistance branch.
Compared with prior art, the utility model has the advantages that:
1, the size of joint action table joystick determining positions output current, and it is defeated directly to control frequency converter frequencyGo out.
2, after power supply input, can change as requested through frequency converter frequency.
3, stepless speed regulation: increase the flatness of speed governing, increase speed adjustable range, adjusting speed accuracy is high, and efficiency is fast;Speed change is steady, nothing is impacted, and can greatly improve the service condition of jib lubbing mechanism and steel construction, has improved tower machineSafety in operation.
4, curent change is little when low, the speed change of starting current, building site electrical network is impacted little, has alleviated userThe burden of electrical network dilatation, power savings is obvious.
5, be easy to implementation procedure automation control.
6, can select to set speed adjustable range, improve the operating efficiency of tower machine, energy-conservation mode of speed regulation, subtractsLack system operation energy consumption.
7, zero-speed band-type brake, and can reduce the wearing and tearing to brake.
8, to adopt the frequency control of Current Control to set lower with regard to bit rate for jib lubbing mechanism, forAccurately lifting.
Brief description of the drawings
The utility model will illustrate by example and with reference to the mode of accompanying drawing, wherein:
Fig. 1 is structural representation of the present utility model.
Detailed description of the invention
A kind of tower machine jib lubbing mechanism frequency-converting speed-governing control system, as shown in Figure 1, comprising: joint action table 1, spacingSignal pickup assembly 2, PLC controller 3, frequency converter 4, luffing motor 5, reductor 6, cylinder 7; Wherein:
Limit signal harvester 2, frequency converter 4 are connected with PLC controller 3 respectively, joint action table 1, changeFrequently device 4, luffing motor 5, reductor 6, cylinder 7 form a sequence loop; Luffing motor 5, decelerationMachine 6, cylinder 7 are jib lubbing mechanism.
Described limit signal harvester 2 is for gathering tower machine mechanism operation shape in tower machine equipment runningThe device of the lead limit switch signal of the stroke of state and limit position limitation protection; Its formation comprises: band shaft jointGear train, cam set, travel switch; No-load voltage ratio relation by gear train is by the operation row of control objectIt is upper that journey situation feeds back to cam running, and with the turned position impact stroke switch of cam, travel switch contact is movingMake (open or close) transmission of signal to controller; Its operation principle is: limit signal harvester is arranged onPrearranged position, when being loaded on hoisting machinery moving component or hitting because of the module of stressed generation distorted movementWhile hitting travel switch, the contact action of lead limit switch, realizes the switching of circuit. Therefore, limit signalHarvester is a kind of according to the travel position of moving component and the electrical equipment of commutation circuit, its action principle withButton is similar. Limit switch is widely used in all kinds of lathes and hoisting machinery, in order to control its stroke, to carry out endEnd position limitation protection. In the luffing control circuit of tower machine, with limit signal harvester input PLC, through PLCLogical operation output control loop control frequency converter output, and then change the speed of jib lubbing mechanism motor,Reach to jib lubbing mechanism forward, position limitation protection effect and safe operation effect backward.
Described joint action table 1 is also provided with electric current speed adjusting module, for the handle position information of joint action table is changedFor the current signal of 4-20mA, enter frequency converter by frequency converter analog input end, frequency converter coding is respectivelyDifferent frequency between corresponding output 0-50Hz, thus make frequency converter drive luffing motor rotation, luffing electricityMachine is carried out forward or action backward, realizes the infinitely variable speeds of luffing motor.
The output current of the electric current speed adjusting module that joint action table handle position determines enters into the analog quantity of frequency converterInput produces velocity magnitude signal, and the goal pace that handle position determines (grasped by driver by this goal paceThe personnel that do need operations linkage platform handle position to determine according to field condition); When the actual speed of luffing motorDetermine lower than handle position goal pace time, frequency converter continues to increase frequency output, makes the reality of luffing motorBorder rotating speed continues to increase; The final actual speed when luffing motor is consistent with the goal pace that handle position determinesTime, frequency converter frequency stable output also keeps; And the position of the frequency of this maintenance and joint action table handle isCoincide. In the time that PLC3 detects direction instruction forward or backward, in conjunction with limit signal harvester 2The limit signal collecting comprehensively judges, PLC3 sends forward or signal backward to frequency converter 4, becomesFrequently device 4 drives luffing motor 5, is carried out forward or action backward by luffing motor 5, Here it is jib lubbing mechanismThe sequence process of system.
Operation principle of the present utility model is:
The first, this control system in the time carrying out stepless speed regulation, position limitation protection function process, runningAs follows:
Above-mentioned whole system, in driver operation tower machine running, the lift hook position of tower machine, or hangHook load-bearing central point is to the moment of tower machine tower body central point, or tower machine suspension hook lift heavy exceedes in advance according to tower machineWhen value that design specification specifies, trigger the travel switch on limit signal harvester 2, limit signal collectionDevice 2 collects (position, moment, lift heavy) limit signal defeated from PLC3 signal input part by circuitEnter PLC3, PLC3 does as follows relatively judgement by built-in logic control program:
1, when PLC3 receives position limit signal that limit signal harvester 2 collects as to front reduction gear orPerson is slowed down backward, PLC3 plug-in judgement output low speed, low speed resistance loop switch connection (PLC3On be defined as the output point of low speed) parallel resistance branch road, make to enter frequency converter analog quantity control loopElectric current reduces according to the choked flow relation of parallel connection shunting; If receiving to front reduction gear or before slowing down backward, PLC3 becomesThe motor speed of width mechanism, in fast state, becomes low speed equally; Like this from the effect of practice,Just make tower machine fast near near the large arm far-end spacing zone limit or large arm in running forward or backwardThe position of end 1 meter of left and right of the limit, reliably slows down, and plays the effect of deceleration position limitation protection; Tower machine suspension hook lift heavy existsIn process, effectively avoid driver's the error large arm of inertial collision that deceleration-operation does not cause far away forward or backwardHead sheave mechanism or the danger of clashing into backward tower body. In like manner, when PLC3 receives limit signal harvesterThe 2 position limit signals that collect are as to front limit or spacing backward, and PLC3 plug-in is judgingMove and stop forward or backward, PLC3 is output point or output point cut-out output backward forward, PLC3 at onceForward output point or backward output point be linked into the rotating direction input of frequency converter, frequency converter direction is defeatedEnter to cut off, frequency converter is out of service, and the luffing motor that frequency converter output is controlled shuts down.
2, same, in the time that PLC3 receives the moment deceleration limit signal that limit signal harvester 2 collects,PLC3 plug-in judgement output low speed, low speed resistance loop switch connection (is defined as on PLC3The output point of low speed) parallel resistance branch road, make the electric current that enters frequency converter analog quantity control loop according to parallel connectionThe choked flow relation of shunting reduces; If PLC3 receives the motor speed of the front jib lubbing mechanism of moment deceleration limit signalIn fast state, become equally low speed; Like this from the effect of practice, just make lift heavy forwardIn running, moment reaches the position of 1 meter of left and right of the characteristic maximum value limit of tower crane load soon, reliableSlow down, play the effect of deceleration position limitation protection; Tower machine suspension hook lift heavy is effectively avoiding driver in running forwardThe error inertia preshoot that deceleration-operation does not cause cause crank, avoid the danger of toppling of tower machine.
3, in the time that PLC3 receives the moment limit signal that limit signal harvester 2 collects, in PLC3Put program judgement and stop forward, output is forward cut off in the judgement of PLC3 logic, and PLC3 forward output point is linked into changeFrequently the direction input of device, the input of frequency converter forward direction is cut off, and frequency converter is out of service, frequency converter outputThe luffing motor of controlling moves and stops forward, only to carry out backward operation.
By above-mentioned detailed annotation position limitation protection function process, running; Ensure that tower machine normally makesWith the safe operation in process.
In the course of the work, joint action table handle position determines tower machine luffing speed-adjusting and control system of the present utility modelThe output current of electric current speed adjusting module enter into the goal pace that the analog input end of frequency converter produces, whenThe actual speed of motor is during lower than goal pace, and frequency converter continues to increase frequency output, and the actual of motor turnedSpeed continues to increase; When the final actual speed when motor is consistent with goal pace, frequency converter frequency stable outputAnd keep; And the position of the frequency of this maintenance and joint action table handle coincide. When PLC3 detect toBefore or when direction instruction backward, the limit signal collecting in conjunction with limit signal harvester 2 is combinedClose judgement, PLC3 sends forward or signal backward to frequency converter 4, and frequency converter 4 drives luffing motor 5, byLuffing motor 5 is carried out forward or action backward, the sequence process of jib lubbing mechanism system that Here it is.
The second, this control system is in the time carrying out stepless speed regulation, and tower machine driver operation joint action table handle, through electricityStream speed adjusting module is sent the different electric currents between (4-20mA), enters change by frequency converter analog input endFrequently device, frequency converter coding is the different frequency between corresponding output 0-50Hz respectively, and frequency converter drives luffing electricityMachine running, luffing motor is carried out forward or action backward, realizes the infinitely variable speeds of luffing motor, improves effectRate; Be embodied in: permanent torque control, and conventional V/F control is exactly permanent torque control in essence, V/FControl be exactly frequency converter output frequency and output voltage ratio be steady state value or direct ratio. Can according to Principle of Electric EngineKnow the virtual value of the every emf phase of threephase asynchronous machine stator: in E1=4.44f1N1 Φ m formula: E1--is fixedThe virtual value of the every electromotive force of being responded to by air-gap flux of son, V; F1--stator frequency, Hz; N1---fixedThe every phase winding effective turn of son; The every utmost point magnetic flux of Φ m-is by finding out in formula, and the value of Φ m is determined by E1/f1Fixed, but because E1 is difficult to direct control, so in the time that electromotive force is higher, can ignore the pressure drop of stator leakage impedance,And replace with stator phase voltage U1. To ensure that so Φ m is constant, as long as U1/f1 is always certain value.In the time of rated speed speed governing once, wish to keep not rated value of every utmost point magnetic flux in motor, if magnetic flux declines,The electromagnetic torque of asynchronous machine will reduce, and will lose like this governing system below base speed when speed governingPermanent torque mechanical property, this is the basic condition of the following timing speed of fundamental frequency, therefore needs constant voltage and frequency ratio (permanent magneticLogical) control mode, belong to speed regulation by constant torque. Reference frequency is the highest frequency in speed regulation by constant torque district, benchmarkThe corresponding voltage of frequency, for being reference voltage, is the ceiling voltage in speed regulation by constant torque district, below fundamental frequencyWhen speed governing, voltage can change with frequency, but both ratio is constant. V/F control mode: frequency converter is adoptedDuring by V/F control mode, the parameter of electric machine is relied on not quite, generally emphasize the size of " no-load current ". ByAdopt the V/F control mode of vector quantization in us, therefore it is static from adjusting or being necessary to do the parameter of electric machine.The frequency converter of different capacity section, it is also different that the no-load current after self study accounts for rated current size percentage. The V/F control mode of vector quantization is also carried out decoupling zero control by input current amount in the time that V/F controls,Make to control more accurate. Frequency converter output current comprises two values: no-load current and torque current, output electricityThe value of stream I is to open 2 powers after no-load current Im and torque current It quadratic sum. Therefore no-load current is to affect frequency conversionOne of principal element of device output current. When V/F controls, output voltage is certain value with the ratio of running frequency:Be V/F=K (K is constant), this formula is described the constant ratio relation between electromotive force and frequency. Frequency converter existsWhen fundamental frequency moves below, along with speed speeds, can export constant torque, speed increases can not be affected and turnThe output of square, is permanent torque output.
The utlity model has following features:
1, use the joint action table of current control mode. Increase the joint action table of electric current speed adjusting module, can be connectionThe handle position information of moving platform is converted to the current signal of 4-20mA, and these current signals can enter frequency converterAnalog input end signal, become frequency converter speed command signal. The joint action table of current control mode is towerMachine luffing method for controlling speed regulation is implemented one of necessary requirement of controlling,
2, according to jib lubbing mechanism job requirement PLC program. The instructions for use of jib lubbing mechanism tower machine operation: withThe handle signal of tower machine driver operation joint action table, provide forward or instruction backward; PLC receives this and refers toOrder, PLC controls according to following logical relation; Forward or backward actuating signal, produce in service inBetween status signal, judge that whether luffing in a safe condition and provide instruction; If safety, time delay obtainingThe luffing frequency conversion band-type brake feedback signal of frequency converter, logic output luffing restraining coil self-sustaining; From in logicPrevent that reverse-starting braking operation maloperation from causing adverse consequences, carry out the spacing judgement of moment, the judgement of transfiniting again in addition,Carry out the judgement of band-type brake logic fault, carry out external fault judgement.
3, converter parameter is set, comprise the corresponding output frequency of size of current, electric motor protecting setting value andRunning parameter etc. A setting parameter control mode has closed loop and open loop, vector controlled, and V/F controls; Purposes choosingBe selected as translation (luffing); The given DC injection braking of B parameter starts frequency, DC injection braking time when startup; C ginsengNumber is set Acceleration and deceleration time, carrier frequency; D setting parameter frequency instruction; E setting parameter frequency converter input electricityPressure, the highest output frequency, the parameter of electric machine; F parameter PG is conventional to be arranged; H setting parameter function terminal; InterlockPlatform handle signal enters after frequency converter through overcurrent speed adjusting module, the limit signal access of limit signal collectorPLC, frequency converter just moves according to the mode of relevant parameters, judges and processes, and output is controlled and is becomeWidth motor.
4, collect concurrent according to lift heavy and driver operation joint action table handle position through limit signal collectorGive PLC, through the relatively judgement of PLC, internal logic computing, output, in conjunction with the setting of frequency converter, combineComposition and division in a proportion judges to adjust exports to the Current Control speed way of output of luffing motor.
Advantage of the present utility model the electric machine speed regulation pattern that uses advanced frequency control to replace to fall behind asAuto-transformer stepping drives double speed or three-speed motor speed governing, and luffing motor is from zero velocity to operation maximum speedAll can accomplish seamlessly transitting of speed, mechanism and structural member, without impact, have been improved to the safety in operation of tower machine;Lower starting current, owing to having used variable frequency starting mode, can make the starting current of variable-frequency motor drop to3 amperes of left and right, lower like this starting current, has good protective effect to motor, plays flexible controlThe effect of system, in like manner lower starting current can not produce large impact to supply line, has alleviated userThe burden of electrical network dilatation; Can select and can set tower machine jib lubbing mechanism frequency control scope, generally correspondingThe electric current output 0-50Hz frequency of 4-20mA, the higher derricking speed of frequency is faster, Here it is jib lubbing mechanism towerThe conventional speed adjustable range of machine frequency control; Improve like this operating efficiency of tower machine, according to different actual needWant to change speed adjustable range is set, as the tower machine according to different tonnages can be set different high speeds, middling speed,Low speed limit value; Energy-conservation mode of speed regulation, just because of adopted frequency control, electric power acting is not wasted like this,Can be unnecessary waste of energy in heating, according to the required size of actual conditions moment, various limit signalsUnder the situation instruction gathering, the motor running frequency of jib lubbing mechanism is adjustable, has reduced system operation energy consumption; OftenWhen in running, jib lubbing mechanism need to be stopped certain position in the process of luffing according to the requirement of workTime, need to stop luffing action, derricking speed reduces to zero; When speed reduces to for zero moment, luffing action is flatSurely stop, band-type brake function is enabled, and is exactly zero-speed band-type brake, and lift heavy horizontal forward like this or operation backward is not noCan be because climb situation unable and that slide in the oversize appearance time-out of tower arm process; Zero-speed band-type brake function reliablySafety while making tower machine jib lubbing mechanism in use ensure load and not rocking, extremely important and worthPay close attention to, and can reduce the wearing and tearing to brake; The frequency control of jib lubbing mechanism employing Current Control canSet lower with regard to bit rate, can be low to moderate 0.01m/s with regard to bit rate, and for accurate lifting.
Claims (3)
1. a tower machine jib lubbing mechanism frequency-converting speed-governing control system, is characterized in that: comprise joint action table, limitPosition signal pickup assembly, PLC controller and frequency converter; Wherein: described limit signal harvester, frequency conversionDevice is connected with PLC controller respectively, and described frequency converter connects with the luffing motor of joint action table and jib lubbing mechanism respectivelyConnect, luffing motor, reductor and the cylinder of described joint action table, frequency converter, jib lubbing mechanism form a sequenceLoop.
2. tower machine jib lubbing mechanism frequency-converting speed-governing control system according to claim 1, is characterized in that:Described joint action table is also provided with electric current speed adjusting module, for the handle position information of joint action table is converted toThe current signal of 4-20mA, enters frequency converter by frequency converter analog input end, and frequency converter coding is right respectivelyShould export the different frequency between 0-50Hz.
3. tower machine jib lubbing mechanism frequency-converting speed-governing control system according to claim 1, is characterized in that:Between PLC controller and frequency converter, there is low speed resistance branch by low speed resistance loop switch in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521103032.0U CN205249113U (en) | 2015-12-28 | 2015-12-28 | Tower machine amplitude changing device variable frequency speed control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521103032.0U CN205249113U (en) | 2015-12-28 | 2015-12-28 | Tower machine amplitude changing device variable frequency speed control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205249113U true CN205249113U (en) | 2016-05-18 |
Family
ID=55948182
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521103032.0U Active CN205249113U (en) | 2015-12-28 | 2015-12-28 | Tower machine amplitude changing device variable frequency speed control system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205249113U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105429558A (en) * | 2015-12-28 | 2016-03-23 | 中科院成都信息技术股份有限公司 | Tower crane luffing mechanism variable frequency speed regulation control system and control method |
| CN109994299A (en) * | 2017-12-29 | 2019-07-09 | 深圳市优必选科技有限公司 | A kind of constant current locking system |
| CN110002341A (en) * | 2019-04-30 | 2019-07-12 | 徐工集团工程机械股份有限公司建设机械分公司 | The method for control speed and system of engineering machinery executing agency execution movement |
-
2015
- 2015-12-28 CN CN201521103032.0U patent/CN205249113U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105429558A (en) * | 2015-12-28 | 2016-03-23 | 中科院成都信息技术股份有限公司 | Tower crane luffing mechanism variable frequency speed regulation control system and control method |
| CN109994299A (en) * | 2017-12-29 | 2019-07-09 | 深圳市优必选科技有限公司 | A kind of constant current locking system |
| CN110002341A (en) * | 2019-04-30 | 2019-07-12 | 徐工集团工程机械股份有限公司建设机械分公司 | The method for control speed and system of engineering machinery executing agency execution movement |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105384084A (en) | Variable-frequency-speed-adjusting control system and method of tower-crane lifting mechanism | |
| CN103043534B (en) | Tower crane hoisting and speed control method | |
| CN105429558A (en) | Tower crane luffing mechanism variable frequency speed regulation control system and control method | |
| CN101665220B (en) | Variable-frequency speed-regulating control system of crane | |
| CN205249113U (en) | Tower machine amplitude changing device variable frequency speed control system | |
| CN205241085U (en) | Tower machine elevating system variable frequency speed control system | |
| CN101704473B (en) | Main lifting parallel operation height balance correcting system of 400-ton bridge crane | |
| CN205241117U (en) | Tower machine rotation mechanism variable frequency speed control system | |
| CN101780920A (en) | Swing mechanism control system for tower crane | |
| CN201530644U (en) | All-digital frequency converting electric control system of mine hoister | |
| CN102647148A (en) | Equipment, method and system used for lifting variable frequency motor and engineering machinery equipment | |
| CN201071258Y (en) | Hook slide preventing crane | |
| CN102530730B (en) | Control system of swing mechanism and tower crane | |
| CN202978810U (en) | Elevating mechanism based on double PWM variable-frequency double-fed motor | |
| CN201534735U (en) | Full digital frequency conversion electric control system control console of mine lifter | |
| CN201557032U (en) | Variable frequency motor and potential energy loading high-speed-ratio frequency conversion system for hoisting machinery | |
| CN204802901U (en) | Tower machine rotation mechanism's stepless speed control control system | |
| CN203582303U (en) | Crane control system driven by outer rotor permanent magnet synchronous motor | |
| CN105384095A (en) | Variable-frequency-speed-adjusting control system and method of tower-crane rotating mechanism | |
| CN210683023U (en) | Double-mechanism synchronous operation lifting control system for tower crane | |
| CN101214907A (en) | Alternating current frequency conversion tyre crane | |
| CN109775583A (en) | Tower crane rotary drive mechanism, rotation control device and tower crane | |
| CN203747716U (en) | Composite-rotor brushless doubly-fed alternating-current motor all-quadrant variable-frequency speed regulation system | |
| CN103338004A (en) | Speed adjustment control system | |
| CN105356509A (en) | Lifting machinery matrix type energy feedback transmission system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |