Talk about transducer to be in of crane apply

Introduction: As the ceaseless development of our country bldg. , those who build construction mechanization level is ceaseless rise, the production quality to tower machine and overall the demand of technical level is higher and higher also. The maneuverability of the means that place of each main transfer machinery of tower machine use, technology standard that controls a system, user and the technical level that can maintain a gender to basically reflect whole tower opportunity and class. One, the overview ceaseless development as our country bldg. , those who build construction mechanization level is ceaseless rise, the production quality to tower machine and overall the demand of technical level is higher and higher also. The maneuverability of the means that place of each main transfer machinery of tower machine use, technology standard that controls a system, user and the technical level that can maintain a gender to basically reflect whole tower opportunity and class. And in these a few orgnaizations, also should be to have a technology most again most representative is hoisting mechanism, it controls power scope of the biggest, timing the widest, maintenance difficulty after giving trouble is the greatest also. And the exhaustion that the mechanical percussive volume that this system generates in gearshift process place will affect tower machine structural member directly injures degree. To improve its performance, domestic each leader produces business to control a technology to went up to already spent a lot of time in the timing of hoisting mechanism, got great progress. Look from whole, what great majority uses is drive of conventional odd electric machinery, give priority to in order to take the plan of the electric machinery of the type that wind a string of eddy current brake and timing of multipolar electric machinery. These traditional timing plan, want to reach wider timing range, its way nothing more than the electric machinery is not mark that designs range of production high-power, wide timing, be like: Use those who take eddy current brake is multipolar the many fast electric machinery that circle line type electric machinery or makes big extreme difference. The taller timing that as a result of tower machine hoisting mechanism place needs asks not only brought more quality to control difficult problem to electric machinery manufacturer, and the production cost that also raised control loop and electric machinery, reduced systematic reliability. Have more very person, ask to the ability removing condole of tower machine as the user bigger and bigger, conventional control means already more and more feel ability not equal to one's ambition, be afore-mentioned technologies no matter can realize a gender, its make the respect such as cost and performance characteristics also be put in a few problems. So, we must seek more perfect new timing to control a technology. In view of the reason of above, domestic and international professional production business is in a rising tone of tower machine undertook more new technology uses an attempt on fast means, for instance: Those who use multipolar electric machinery is pressure regulating timing, introduce frequency control to wait. Gradually, as the ceaseless development of frequency conversion technology, be known by people ceaselessly, it surpassed any other timing program with very preponderance, its actor or actress check the number is counted deeply, be like: 0 fast hold brake in the arms, do not have to brake wear away; The perch rate with low random, can use at accurate hoisting; The smooth glide of speed is crossed, do not have concussion to orgnaization and structural member, enhanced the moving security of tower machine; Extremely small starting electric current, reduced the burden that enlarge of user electrified wire netting allows; Almost aleatoric wide timing range, improved the work efficiency of tower machine; Energy-saving timing pattern, reduced a system to run specific power consumption; Odd fast the moving dependability that squirrel cage electromotor assured an orgnaization . Mix because of these apparent characteristics just about advantage, the hoisting mechanism of the machine of new generation tower that tower aircraft manufacturer of abroad rolls out also adopts frequency control plan mostly, be like POTAIN, the world-renowned company such as LIEBHERR. At the same time we think, as transducer price reduce ceaselessly, dependability rises ceaselessly, frequency conversion technology can get applied extensively on tower machine certainly, this will have important sense to the safety of the product moves and reducing moving specific power consumption. To popularize frequency conversion technology, deepen the understanding of pair of frequency control plan, the article will be in to frequency conversion technology the application on hoisting mechanism makes tower machine be discussed. 2, hoisting mechanism of groovy frequency conversion 1. Technology of structural introduction frequency control the time that in tower machine the application of each main transfer machinery is in our country to had had nearly 10 years, although gained the applied experience of a few successes, and also have not little frequency conversion hoisting mechanism moving normally in building site now, but compare with other industry posture, frequency control technology has not reached due level far in the application on tower machine, have the reason of cost among them, also have technical reason. The typical plan that home and abroad adopt at present, will tell from the technology, very much the same, differentia depends on: (1) the brand of transducer is different, the control return circuit that its use is different; (2) the system is open loop (do not take PG) or closed circuit (take PG) (3) of the form of rigid structure different: L decorate, п decorate or one word decorate etc; (4) the type of decelerate machine is different, be like: Machine of columnar gear decelerate or planetary decelerate machine; It is to decide speed ratio or alterable speed ratio to wait. With respect to transmission control technology character, above place narrates difference to did not involve the change that controls fashion, all have the typical pattern of timing to use a transducer to control an electromotor, also call its hoisting mechanism of groovy frequency conversion. Be in all in orgnaizations of these groovy frequency conversion, the characteristic of the frequency conversion hoisting mechanism that LIEBHERR company assembles on EC-H tower machine is most outstanding, it uses 250V electromotor and the transducer that match to it, deploy the decelerate aircraft of alterable speed ratio, l decorate. This plan has better load-lifting speed character, its defect is systematic cost tall, and component versatility is poor. 2. The design of hoisting mechanism of groovy frequency conversion should nod (1) electromotor extremely the school nucleus of number and power becomes the basic parameter of hoisting mechanism (be like: Rate of the largest lifting capacity, top job) after giving, be about to be opposite of electromotor extremely number and power undertake decide and be computationaled, its design a point is: A) electromotor output rotate speed should is less than 3000 turn / cent (the working rotate speed that inputs class by decelerate machine is restricted) ; B) top job frequency should be less than the system 100Hz (frequency is taller, the loss power of electromotor is greater, will destroy constant power character, ability removing condole is reduced substantially and do not have actual application value) ; C) rated torsion uses motor at school nucleus the largest lifting capacity (consideration total drive is compared, efficiency, fold) ; D) the lifting capacity when the rated power of electromotor is used at school nucleus high speed (consideration total drive is compared, efficiency, fold, if frequency is close to 100Hz, should consider effective power to reduce 10 ～ 15 ％ ) . When choosing electric machinery power, decrease with respect to what can define decelerate aircraft basically according to the condition of above speed ratio and electromotor power and extremely several. (2) electronic-controlled design A of the system) of transducer after choosing the electromotor when the system to decide, undertake controlling systematic design with respect to hand of manage to make do. It is the type selecting of transducer above all. The brand of domestic and international transducer on the market is not little now, control level and dependability difference are bigger, the cardinal principle on the technology can be divided for V/F control, vector control and DTC direct torsion controls 3 kinds. Use at the hoisting mechanism of tower machine, the proposal had better choose appliance to vector controls a function to perhaps have DTC the transducer of function of direct torsion control, such transducer brand is more, the element such as the use case that the architect can back factory of strength, other industry according to his familiar degree, technology will choose. As a result of transducer brand different, the overload ability of the transducer below same power and value of rated electric current agree not completely also. So, when choosing transducer capacity, want to see the size of rated power not simply, whether rated job electric current is more than school nucleus or be equal to the rated electric current of electromotor even, the power that general experience is choice transducer is more than electromotor power 30 ％ of 10 ～ are controlled. B) of resistor of specific power consumption choose regard a frequency conversion of put sb in a very important position as the system, the key that its design depends on electromotor be in the systematic dependability below regenerative braking condition, because this kind of system goes breakdown to often happen in the operating mode when the clog drops, if sneak away hook, overspeed, press too etc. That is to say the clog drops the function stand or fall of system of the frequency conversion when operating mode will affect whole hoisting mechanism directly whether safety moves. This is about to beg those who design personnel to understand system of frequency conversion transmission clearly to pass on working process, ability accomplishs know fairly well. In the product specification of major transducer, do not have very clear description to how choosing the resistance of resistor of specific power consumption and power, and the requirement that the level that often recommends by its is configured and cannot satisfy a heavy operating mode completely, the implied meaning that discusses about this respect at the same time also does not see more, be in so since frequency conversion in the design that controls a system again, resistor parameter chooses to appear a little confused. The article will work to undertake qualitative analysis in the working mechanism of the system when regenerative braking condition to electric machinery, the reader can get concerned the computational method of resistor parameter further through these analysises. Of ① resistance choose the parameter that can give out basically by transducer example to decide, basic principle is, the voltage that considers dc return (the clog drops 600VDC will exceed when operating mode) below the circumstance, the electric current on resistor does not exceed the rated electric current of transducer. Of ② resistor power choosing the power that should choose resistor well and truly is very important, if the selection is too big, can raise systematic cost, too small can cause those who move is fluky. But the power that should choose resistor of specific power consumption well and truly is one relatively the thing of loaded down with trivial details, the factor that affects this parameter is more, be like: Machine of volume of electric machinery power, decelerate is retrorse efficiency, drop the metropolis such as the moment of inertia of run time of the size of run time accident, negative acceleration, slowdown and drive disk assembly affects resistor power choose. So, we drop so that be in from analytic system above all the working process of operating mode, get resistor power decides a method really thereby. The fall of the clog power is classics " drive disk assembly " , " electromotor " (be in right now generate electricity condition) , the retrorse commutate loop inside transducer is delivered by unit of apply the brake again " resistor R " those who go up, if the retrorse efficiency of transmission link is lower, the power that consumes on resistor is less. Have then: "Resistor R " calorific consume power + the expression that delivers the power that the power = clog that uses up on method drops to return attainable resistor to use up power P further: In divide evenly fast power comsumption of the stable state when dropping: In type of ① of δ of × of Me of × of Pe= ω M: δ is the peak value power comsumption when the retrorse efficiency decelerate of transmission system: × of J of Pm=Pe+ δ × (D of ω M- ω ) / in Ta ② type: The moment of inertia that J is transmission system combines type ① and type ② to have: When hoisting mechanism moves in rated power condition and high speed drops, if give out right now,decelerate dictates, in the initial stage of decelerate, of resistor use up power to will reach maximum; Spend short slowdown time, will cause what go up in resistor to use up power peak value to rise; Systematic moment of inertia and load are bigger, the torsion of apply the brake when decelerate is taller, also can cause the peak value that consumes power on resistor to rise; The mechanical efficiency when transmission system is lower, resistor consumes power lower also. Visible, want well and truly computation resistor to consume power, the time length of process of the initial work rate with corresponding dot of the moment of inertia that must know each parts in transmission system, decelerate and end activity speed, decelerate and systematic load size. Want to determine the exact value of these parameter, designing initial stage in the system have certain difficulty, one of, before the product is half-baked, cannot be measured accurately or calculate the moment of inertia of each drive disk assembly; Secondly, in be used actually, can follow the need of the spot and decelerate feature of the system is changed. So big much case falls, resistor power did not make strict calculation. Between the 70 ％ of 40 ～ that the extraction of experience is worth is electric machinery power commonly, when the retrorse efficiency of decelerate machine is inferior, can choose lesser resistor power. Wanted to know the working position of the decelerate process of frequency conversion system adequately only, with respect to the real work that can design a system according to place expression amends resistor parameter. C) control program is the option that the system uses open loop or closed-loop control above all surely really, the author thinks, hoisting mechanism can use average tower machine open loop controls fashion, those control precision to ask higher case just wants to consider closed-loop control to speed. If want to make closed circuit system, must have PG (coder) , detect loop and jumper. These link increased the complexity of installation; Raised systematic cost; More important is the reliability that reduced a system, because be in closed circuit system, any petty accident may cause feedback return the system is disorder. It is speed next those who give way choose, the transducer of great majority has a variety of speed to input means, if multistage switch measures input means and imitate quantity to give way, the transducer of many brands still provides communication interface of stock bus line. To hoisting mechanism of groovy frequency conversion, use switch quantity to be given as speed mostly, different using PLC or afterwards report logic to control then. The author thinks, most compact construction of system should be by PLC and transducer communication interface deferent speed and control are dictated, such, the jumper inside control ark is least. 3, hoisting mechanism of double frequency conversion 1. The necessity that develops hoisting mechanism of double frequency conversion so far, transducer is in the history that the application on hoisting mechanism had had tower opportunity nearly 10 years, from afore-mentioned analysises we know, frequency control technology can give tower chance move bring more profit, and the symposium that department of concerned technology promotion and guild also had run application of frequency conversion technology for many times, but use an amount actually and not ideal, only minority has the leader plant of actual strength to had rolled out frequency conversion hoisting mechanism inside course of study, this is far cannot compare with the applied rate photograph of other industry. Reason thinks, restricting the main reason that frequency conversion technology popularizes inside the industry is: The after service difficulty after occurrence breakdown of frequency conversion system is great, compare with groovy system photograph, increased the shutdown maintenance time of tower machine, increased the shutdown loss of the user; Frequency conversion controls systematic cost to want hoisting mechanism of prep above convention, increased to popularize difficulty; The 60 ％ left and right sides of cost of frequency conversion hoisting mechanism is transducer, because the price of transducer is at present higher, so systematic totle drilling cost wants hoisting mechanism of prep above convention, but as frequency conversion technology gain ground ceaselessly and rise, the price of transducer still has bigger fall space, and the cost of groovy hoisting mechanism already did not have latent capacity basically to be able to be dug. We believe, be in before long in the future, the cost of groovy hoisting mechanism will not have very preponderance but character. So, the urgent affairs of industry technology worker is how can design the frequency conversion hoisting system that eases after service pressure. 2. The exercise state analysis of hoisting mechanism weighs tower chance the working ability of machine of a tower, it is the largest lifting capacity that matchs hoisting mechanism not simply this one parameter, and the size that more important parameter is working moment of force, it is the main index that tower machine safety runs. As a result of the limitation of pitching moment parameter, tower machine is impossible to can remove condole below any working extent of the largest lifting capacity, and from the effective use of building site spot travel case looks, a string of 1 the operating mode of the greatest weight also is very little since tower machine. The 5613 towers engine that couplet company produces in, the largest lifting capacity of this tower machine is 8t, radius of the biggest job is 56m. "Carry a district gently " lifting capacity is less than 4t, working radius is 56m, work area is 9847m2; "Burden area " lifting capacity is more than 4t, working radius is 24m, work area is 1808m2; "Be fully loaded with " area lifting capacity is equal to 8t, working radius is 14m, work area is 615m2; Its job dead band (the car is the smallest working radius) it is 3m about, the area is 28m2. Get through computation: If regard the dividing line of light burden as the dot with the weight removing condole of 4t, "Burden area " work area is occupied only " carry a district gently " the 18 ％ of work area. And go to the effective use of tower machine in building site case count, one deploys 8t the tower machine of hoisting mechanism, the operating mode that has load of condole 4t above truly is very little. The analysis that passes above has: The halve of ability removing condole of tower machine, the operating mode of 80 ％ above is insusceptible. This offerred a train of thought to us: Two electromotor that if mix those who have by an electromotor,hoisting mechanism of frequency conversion of pilot of a transducer changes a success to lead halve and two small transducer come the word of collective drive, although have electric machinery or transducer occurrence breakdown, tower machine is OK still below majority circumstance as usual works. Reduced the after service pressure of leader plant greatly so, very advantageous also to the user. To tower machine this is planted special crane, it is OK that if hoisting mechanism uses,plan promotes since double frequency conversion: When carrying gently, odd electric machinery moves, can achieve energy-saving with the purpose that prolongs systematic life; When one transducer damages, but odd electric machinery works, the system will break a breakdown loop automatically, can accomplish ceaseless to the system machine to maintain, reduced the pressure after the carry out of tower aircraft manufacturer greatly; After an electromotor gives trouble, can use means of job of odd electric machinery likewise, do not affect tower mechanic to make below majority operating mode; Below burden, double electric machinery works, satisfy the operation requirement of tower machine with perfect frequency conversion function; Decrescent of each power component, decreased to maintain cost and difficulty. This system already was mixed through detecting strictly industrial assessment, function achieved design requirement. We think, the hoisting mechanism of double frequency conversion that article place discusses is to was industry of machine of our country tower to find a feasible new thinking on the application of frequency control technology, standards of this pair of tower machine technology that promote our country, can maintain the gender, after service pressure that reduces leader plant and the active sense with reduce the technical gap that travels together with abroad to have important what improve a system. CNC Milling