CN1033338A - Eddy current brake speed regulator - Google Patents
Eddy current brake speed regulator Download PDFInfo
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- CN1033338A CN1033338A CN 87107920 CN87107920A CN1033338A CN 1033338 A CN1033338 A CN 1033338A CN 87107920 CN87107920 CN 87107920 CN 87107920 A CN87107920 A CN 87107920A CN 1033338 A CN1033338 A CN 1033338A
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- speed
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- eddy
- current brake
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Abstract
The present invention is a kind of eddy current brake speed regulator that is used for crane hoisting mechanism, and it is made an amendment slightly, also can be used for mechanisms such as the demanding walking of speed adjusting performance, luffing, revolution.The present invention adopts the rotor frequency that detects induction motor, and its frequency is converted apace to the technical scheme of voltage.Also on the basis of speed closed loop, set up the electric current loop that overcomes the eddy-current brake electrical inertia, safe and reliable in order to ensure system set up exciting current fast rise compensation tache, exciting current whole process supervision link and the braking link of pausing again.The speed adjusting performance of this system can reach speed ratio 1: 10, momentary speed variation ± △ n%≤± 1.5%.
Description
The invention belongs to the dynamo-electric brake category, is that a kind of rotor frequency with induction motor is as the rotating speed of speed feedback, the eddy current brake speed regulator of current double closed-loop.
The speed control principle of eddy-current brake Closed-Loop Speed Governing System, be set-point signal by rotating speed and actual value signal relatively after, the brake torque that makes the exciting current of system's increase and decrease eddy-current brake regulate eddy-current brake.Closed-loop system under the given rotating speed condition, the electronic torque M that the brake torque MW of eddy-current brake must produce with motor
DAnd lift heavy is folded to the load torque Mfz balance on the motor reel.Be MW=M
D± Mfz(Mfz is "-" when rising, and is "+" during decline).For this reason, governing system is automatically regulated exciting current, can make controlling object (lifting mechanism) by given rotating speed operation.Existing eddy current brake speed regulator has 4 deficiencies technically:
1, speed measuring device of the prior art, the detection mode of its rotary speed actual value generally adopts the mode of tachogenerator or detection rotor voltage.
United States Patent (USP) NO.3886255 has introduced and has adopted alternating current tachogenerator to detect the speed-regulating actuator of rotating speed.Its tachometer is the cost height not only, and mechanical wear is arranged, and difficulty is installed simultaneously, needs frequent maintaining.In addition, when mechanism operated in 10% or 20% rated speed, generator was under the low speed situation and moves.Because speed is low, reduced the rate accuracy of tachometer, influence speed adjusting performance.
Dalian Low-Voltage Switch Factory QD-100 type in 1984 eddy-current brake automatic control equipment is to adopt to detect the induction motor rotor voltage, detects the example of rotating speed indirectly.We know that the rotor voltage of induction motor is the same with stator voltage, are subjected to the influence of voltage drop on the influence of factory building voltage fluctuation and the factory building slip.Therefore, this mode has reduced rate accuracy widely, has influenced speed adjusting performance.
2, do not overcome the electrical inertia of eddy-current brake in the prior art well.The device of above-mentioned United States Patent (USP) and big low factory, all be rotating speed list closed-loop system, promptly rotary speed setting value and actual value relatively after, the difference of generation is through speed regulator, make the electric current of silicon controlled rectifier control flows, thereby reach the purpose of speed regulation through eddy-current brake.We know that the excitation winding of eddy-current brake has bigger inductance value, and promptly the electrical inertia time constant is bigger.In this case, though der Geschwindigkeitkreis has output, exciting current can not respond fast.Therefore, the lifting mechanism of above-mentioned single closed-loop system in order to prevent under the weight to slip, adopts the passive exciting current of waiting for eddy-current brake to rise to (waiting for 1～2 second approximately) behind the setting, just allow the brake rubber block of release mechanism brake.This has brought trouble to driver operation.
3, exciting current is not carried out whole process supervision in the prior art.The device of above-mentioned United States Patent (USP) and big low factory mainly starts moment to exciting current implementation monitoring, and the exciting current monitoring link be not set in running.Like this, in case exciting current is lost in the running, it is synchronous speed that motor will speed up 1.5no(no) after, send signal by overspeed switch and make the mechanical brake braking.This braking method, its security reliability is poor.To the lifting mechanism after using for a long time, when moving, in case exciting current is lost, serious accident may take place particularly under full load situation.
4, the pause braking link that reduces the brake rubber block wearing and tearing is not set in the prior art, when driver operation stops, often the handgrip of master controller directly is withdrawn into the zero-bit shelves from top gear.At this moment, mechanical brake stops from braking by force at a high speed, so brake skin quick abrasion, brakes not steady.
The objective of the invention is to overcome the deficiency of prior art, propose a kind of eddy current brake speed regulator of novelty.The speed adjusting performance of this system can reach speed ratio 1: 10, momentary speed variation ± △ n%≤± 1.5%, (± △ n%=± △ n/no * 100%).And it is fast to have a dynamic response, system features in convenient, and the brake rubber block wearing and tearing are few, stable performance and play advantages such as braking is steady during low cruise.Native system makes an amendment except being used for crane hoisting mechanism slightly, also can be used for having the mechanism such as walking, luffing, revolution of high speed governing requirement.
The present invention is directed to the deficiencies in the prior art, propose in eddy current brake speed regulator, to adopt the rotor frequency that detects induction motor, and its frequency is converted apace to the technical scheme of voltage.
We know, when mains frequency just often, the relation that the rotor frequency of induction motor and rotating speed reduce linearly.The worst error of China regulation 50HZ mains frequency is ± 0.5HZ.Be that precision is ± 1%.China stipulates the pressure drop on voltage ripple of power network and the factory building slip equally, and its voltage maximum fluctuation value can reach-15%U
EAs compare accurate 15 times of frequency ratio voltage with worst error.For this reason, need only the frequency of detection rotor and it is converted to voltage, can obtain precision high rotational speed feedback signal.We also know, wave 0HZ or 30HZ when motor operates in the long-drawn-out moral hand of the 10% or 20% synchronous brave guarantor apricot Φ Duo mire of commentaries on classics.Therefore, this frequency inverted is become voltage, if also will keep certain precision, the time constant of its conversion is bigger.To this bigger lag time constant,, the normal operation of system will be influenced as not really good processing.The present invention proposes to make full use of the characteristics that the induction electric machine rotor also has three-phase in eddy current brake speed regulator, adopts three-phase bridge rectification and shaping.At this moment rotor frequency with only utilize after single-phase rectifier and the shaping half-wave relatively, it is increased to six times equivalently.For this reason, frequency inverted becomes the time constant of voltage, and just reducing becomes original 1/6.By the rotor frequency electric pressure converter of constant between this trial-production three-phase type hour, and the design correspondent control circuits, it is little just can to obtain time constant, the speed feedback signal that precision is high.
In order to overcome the electrical inertia of eddy-current brake, electric current loop and exciting current fast rise compensation tache are set.As everyone knows, the inductance value of the excitation winding of eddy-current brake is bigger, and it delays the fast rise of exciting current.For this reason, be provided with electric current loop specially, surround the electrical inertia of excitation winding, constitute a current feedback correction link by it.Because electric current loop has been arranged, the electrical inertia time constant of excitation winding has reduced, and this has just accelerated the rate of climb of exciting current.But, start moment, the electrical inertia time constant that reduces in the electric current loop is also delaying the fast rise of exciting current in varying degrees.Do not produce the moving phenomenon of downward slide in order to ensure the workpiece that is in freely falling body (starting moment mechanical brake has unclamped brake rubber block), so set up the zooming compensation tache of exciting current again.Like this, start moment, when electric current loop also had little time to play a role, compensation tache had made the brake torque that eddy-current brake produces is enough to prevent slide under the workpiece.After the starting, when der Geschwindigkeitkreis has had output, whole governing system is pressed the given speed operation.Like this, when the driver was placed on the operation of speed governing shelves to the master controller handgrip, lifting mechanism can be not only quick but also correctly workpiece is rested on the required position of stopping.
For fear of producing hypervelocity, set up exciting current whole process supervision link.Bicyclic system is except carrying out the monitoring monitoring link when also setting up the operation of decline speed governing shelves in starting moment to exciting current.When system when moving, just in case exciting current is lost, just system sends trouble signal at 0.2no, and makes the mechanical brake braking at speed governing shelves (supposition 0.2no).Realize whole process supervision, need trial-production current monitoring relay and design correspondent control circuits.
In order to reduce the brake rubber block wearing and tearing, set up the braking link of pausing.The lifting mechanism of crane often is under motor rated speed (at a high speed) situation and moves.When stopping, driver's operation often is directly to move the zero-bit shelves to from top gear.Be till mechanical brake will be braked parking by force from high speed.This mode of braking brake rubber block quick abrasion, poor stop.For this reason, set up the deficiency that the braking link of pausing remedies prior art.After setting up the braking link of pausing, the driver directly moves the effect that bicyclic system behind the zero-bit shelves has just been brought into play electric current loop to from top gear again.Electric current loop is regulated the brake torque of eddy-current brake, make lifting mechanism by etc. deceleration brake.After braking 10% rated speed, brake by mechanical brake again and stop.So not only avoided the quick wearing and tearing of brake rubber block, can utilize hydraulic pressure to push away again and defend brake, made braking ability very steady.For this reason, trial-production speed monitoring relay and design correspondent control circuits, the braking link just can obtain to pause.
The present invention can also pass through the following examples, further is illustrated with reference to accompanying drawing.
Fig. 1 is rotating speed, the current double closed-loop eddy-current brake speed governing block diagram of lifting mechanism.
Fig. 2 is torque, the rotary speed property figure of lifting mechanism.
Torque when Fig. 3 is the lifting mechanism rising, rotary speed property figure.
Torque when Fig. 4 is lifting mechanism decline, rotary speed property figure.
Uphill process:
During starting, except preventing that workpiece from not slipping down, pursue the rapidity of system again.Therefore, as feedback voltage U
FnGreater than given voltage U
GnThe time, speed regulator is owing to there being diode clamp not have output, and current regulator is not input just.But exciting current fast rise compensation tache U
BSExisting voltage, U
BSMake eddy-current brake flow through a rated current value fast, after this electric current made the current monitoring actuating of relay, even mechanical brake is opened, governing system was devoted oneself to work immediately.
During speed governing shelves " 1 " operation, mechanism presses rising characteristic among Fig. 3 (3) and quickens, up to U
FnLess than U
GnThe time, the saturated output of speed regulator, current regulator work.Current regulator is regulated the exciting current of eddy-current brake, makes the brake torque MW=M of eddy-current brake
D-M
FZ, see that mechanism is at 0.1n among Fig. 3
oM during operation
W, M
D, M
FZNumerical value.As the driver master controller handgrip is rested on rising " 2 " shelves, the adjuster working condition is same with " 1 " shelves, but mechanism is at 0.2n
oWork.
Exciting current is lost when starting, and the master controller handle rests on rising " 1 ", " 2 " shelves, at that time, except that mechanism's akinesia, also sends trouble signal.After the starting, still at rise " 1 ", " 2 " shelves, machinery is in running status to the master controller handle, as the fault that exciting current is lost takes place, except that mechanical brake carries out brake hard, also sends trouble signal.
The driver enters non-speed governing shelves " 3 ", " 4 " to operating grip from speed governing shelves " 1 ", " 2 ", and its characteristic is pressed (3) among Fig. 3, (4) curve motion.The driver is as moving the zero-bit shelves from " 4 ", " 3 " shelves to through " 2 ", " 1 " shelves, or promptly gets back to the zero-bit shelves, and the braking link of pausing is had an effect.Promptly brake by eddy-current brake earlier, measure rotating speed when FV convertor and reached 0.1n
oAfter, mechanical brake is braked and is stopped.
The decline process:
During starting, prevent that workpiece from not slipping down and the rapidity of the system of pursuit and uphill process with, during speed governing shelves " 1 " operation, characteristic curve FC acceleration among Fig. 4 is pressed by mechanism, up to U
FnLess than U
GnThe time, the saturated output of speed regulator, current regulator work.Current regulator is regulated the exciting current of eddy-current brake, makes the brake torque M of eddy-current brake
W=M
D+ M
FZ, see that mechanism is at 0.1n among Fig. 4
oM during operation
W, M
DAnd M
FzNumerical value.As the driver handgrip of master controller is rested on decline " 2 " shelves, the working condition of adjuster and decline " 1 " shelves are same, but mechanism operates in 0.2n
o
Exciting current the time is lost in starting and operation, its system works situation when rising with.
When non-speed governing shelves were moved the zero-bit shelves to, the braking link of pausing and rising were together.
Claims (5)
1, a kind of eddy current brake speed regulator, be to utilize to detect the rotating speed list closed-loop system of induction motor rotor voltage as speed feedback signal, when rotary speed setting value and actual value when relatively the back produces difference, this difference is through speed regulator, make silicon controlled rectifier regulate the brake torque of eddy-current brake, system is moved under given rotating speed, it is characterized in that described governing system is on the basis of speed closed loop, set up the electric current loop that overcomes the eddy-current brake electrical inertia, safe and reliable in order to ensure system, set up exciting current fast rise compensation tache again, the exciting current whole process supervision link and the braking link of pausing, the speed feedback signal of described speed closed loop, be to adopt the rotor frequency that detects induction motor, and frequency converted fast to the speed-measuring method of voltage.
2, according to the described eddy current brake speed regulator of claim 1, it is characterized in that described with the rotor frequency that detects induction motor speed-measuring method as speed feedback signal, be to have utilized motor rotor to have the characteristics of three-phase, after the three-phase bridge rectification shaping, with the mode of single-phase rotor frequency equivalence multiplication.
3,, it is characterized in that the mode of described rotor frequency equivalence multiplication is meant: adopt three-phase type FV convertor and design correspondent control circuits according to claim 1 or 2 described eddy current brake speed regulators.
4,, it is characterized in that described exciting current whole process supervision link is meant employing current monitoring relay and design correspondent control circuits according to the described eddy current brake speed regulator of claim 1.
5, according to the described eddy current brake speed regulator of claim 1, it is characterized in that described pause braking link, be meant and adopt speed monitoring relay and design correspondent control circuits.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87107920 CN1033338A (en) | 1987-11-20 | 1987-11-20 | Eddy current brake speed regulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87107920 CN1033338A (en) | 1987-11-20 | 1987-11-20 | Eddy current brake speed regulator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1033338A true CN1033338A (en) | 1989-06-07 |
Family
ID=4816294
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 87107920 Pending CN1033338A (en) | 1987-11-20 | 1987-11-20 | Eddy current brake speed regulator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1033338A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102107088A (en) * | 2009-12-24 | 2011-06-29 | 斯平玛斯特有限公司 | Velocity feedback control system for a rotor of a toy helicopter |
| CN102780449A (en) * | 2012-07-23 | 2012-11-14 | 中联重科股份有限公司 | Equipment, system and method for controlling slewing speed regulation of tower crane, and tower crane |
| CN105373151A (en) * | 2015-12-23 | 2016-03-02 | 高显明 | Vibration machine vibration frequency closed-loop control device |
-
1987
- 1987-11-20 CN CN 87107920 patent/CN1033338A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102107088A (en) * | 2009-12-24 | 2011-06-29 | 斯平玛斯特有限公司 | Velocity feedback control system for a rotor of a toy helicopter |
| CN102107088B (en) * | 2009-12-24 | 2013-12-25 | 斯平玛斯特有限公司 | Velocity feedback control system for rotor of toy helicopter |
| CN102780449A (en) * | 2012-07-23 | 2012-11-14 | 中联重科股份有限公司 | Equipment, system and method for controlling slewing speed regulation of tower crane, and tower crane |
| CN102780449B (en) * | 2012-07-23 | 2015-08-12 | 中联重科股份有限公司 | Tower machine revolution speed regulating control equipment, system, method and tower machine |
| CN105373151A (en) * | 2015-12-23 | 2016-03-02 | 高显明 | Vibration machine vibration frequency closed-loop control device |
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