CN103001185A - Warning method for instantaneous overload of cold rolling production line looper motor - Google Patents
Warning method for instantaneous overload of cold rolling production line looper motor Download PDFInfo
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- CN103001185A CN103001185A CN201110272512XA CN201110272512A CN103001185A CN 103001185 A CN103001185 A CN 103001185A CN 201110272512X A CN201110272512X A CN 201110272512XA CN 201110272512 A CN201110272512 A CN 201110272512A CN 103001185 A CN103001185 A CN 103001185A
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Abstract
The invention relates to a fault warning method for a cold rolling production line looper, in particular to a warning method for instantaneous overload of a cold rolling production line looper motor. The method includes: firstly, according to time t decreasing along with increase of current i during overload, determining the relation between the time and the current conforming to the formula: delay time t=K/(in-1) when the current is i, wherein K=80, and n=2; secondly, respectively substituting 90% of motor current instantaneous load and 150% of the motor current instantaneous load into the formula, and obtaining the minimum delay time t1 and the maximum delay time t2 respectively through the formula, wherein t1=1m, and t2=21s; and thirdly, dividing a delay time span into seven segments, computing the corresponding delay time according to the algorithm, and when instantaneous current reaches 90% of the load, starting to computing a t value according to the formula and judging whether warning or not according to the size of the t value. The method is capable of avoiding instantaneous impact load which cannot be avoided by a general warning model, and eliminating frequent false warning of the looper current load.
Description
Technical field
The present invention relates to the rolling mill production line fault pre-alarming, relate in particular to a kind of fault early warning method of rolling mill production line loop back roll.
Background technology
In the cold rolled continuous annealing process, strip speed is stablized constant in the stove, the kink section is by to rushing cover and putting cover with steel, played the effect of speed-bufferings before and after the annealing section strip steel, however kink when beginning to fill cover or beginning to put cover, the impact that loop back roll is subject to is larger, roller speed changes also larger, motor load and roller speed are varied to direct ratio, and current of electric can instantaneously surpass nominal load, and this phenomenon is normal from the angle that drags principle.Current setting value and actual value compare calculating during loop back roll motor stable state that former method only provides by PLC, draw the early warning conclusion, ignored and filled cover and put the moment impact that brings in the cover process, so this early warning can't escape instantaneous impact load, cause the phenomenon of the frequent false alarm of loop back roll current capacity.
Summary of the invention
The present invention is intended to address the aforementioned drawbacks, the method that provides a kind of rolling mill production line loop back roll motor instantaneous overload to report to the police.The temporary impact load that the present invention can avoid general Early-warning Model to escape, the phenomenon of the frequent false alarm of elimination loop back roll current capacity.
For addressing the above problem, the method that a kind of rolling mill production line loop back roll motor instantaneous overload is reported to the police,
Step 1, time t reduces with the current i increase during according to overload, determines that time and current relationship meet following formula:
Delay time t=K/ (i when electric current is i
n-1);
K=80 wherein; N=2;
Step 2 with current of electric momentary load 90% and 150% difference substitution following formula, by following formula, draws the minimax delay time and is respectively: t1=1m, t2=21s;
Step 3 is divided into 7 sections with delay time length, calculates corresponding delay time according to above algorithm, and when transient current reached load 90%, beginning was calculated the t value according to following formula, judges whether to report to the police according to t value size:
When the loop back roll load〉90% also lasting 1m, then report to the police
When the loop back roll load〉100% also lasting 48s, then report to the police
When the loop back roll load〉110% also lasting 40s, then report to the police
When the loop back roll load〉120% also lasting 33s, then report to the police
When the loop back roll load〉130% also lasting 28s, then report to the police
When the loop back roll load〉140% also lasting 24s, then report to the police
When the loop back roll load〉150% also lasting 21s, then report to the police.
Because the band steel is in the cold rolled continuous annealing process, entrance and outlet looping are namely being controlled band steel throughput and are being changed closely bound up with strip tension again, the variation of throughput and the imbalance of strip tension all may cause loop back roll current of electric overload, in case electric current sustained overload, the roller electrical fault causes band steel broken belt.Loop back roll load and roller speed are varied to direct ratio, and former early warning system is come the broken belt that caused by motor in the early warning kink by the monitoring to motor load.
Original system does not have perfect warning function for kink motor momentary overload, only having load to reach 150% and the function of the 1m tripping operation of delaying time, and this function is as protection and can not be as prevention.If loop back roll motor trip protection may cause the accident of shutting down completely, therefore the early warning for the motor instantaneous overload is very necessary, and key is how to design Early-warning Model.According to dragging principle, the power characteristic of motor has the inverse time lag characteristics, and inverse time over-current protection refers to a kind of protected mode of automatically reducing with the increase of short circuit current operate time.
The present invention no longer considers speed, and after transient current exceeded standard value, pre-warning time set point and load current were inverse ratio, forms a function curve that successively decreases.The present invention wishes to concern to eliminate the warning that mistake that temporary impact causes brings by the function curve of setting up current loading and time.The temporary impact load that method of the present invention can avoid general Early-warning Model to escape, the phenomenon of the frequent false alarm of elimination loop back roll current capacity.
Description of drawings
The present invention is further illustrated below in conjunction with accompanying drawing:
Fig. 1 is described anti-time limit characteristic curve synoptic diagram.
Abscissa is the time T axle among the figure, and ordinate is the electric current I axle.
Embodiment
New algorithm is no longer considered speed, and after transient current exceeded standard value, pre-warning time set point and negative current were inverse ratio, forms a function curve that successively decreases.
The anti-time limit characteristic principle as shown in Figure 1.Electric current is larger, and operation time limit is shorter.
T reduces with the electric current increase among Fig. 1, when limit value t when exceeding, load current still surpass a certain limit value, then thinks the moment overload current.The algorithm of t value is:
t=K/(i
n-1)
K and n are constant in the formula, draw K=80, n=2 according to analysis, test and experience.
T is the delay time when electric current is i.
I is larger, and then t is less, allows the time of overload shorter; I is less, allows overload time just longer.
With current of electric momentary load 90% and 150% difference substitution following formula, by the curved line relation of following formula algorithm, draw the minimax delay time and be respectively: t1=1m, t2=21s, through test, delay time meets on-site actual situations.
Consider that curent change is very fast, Early-warning Model need to be finished in PLC, each variation all need be revised delay time one time, and PLC itself is not with database, can not support the storage of mass data, so time-delay is divided into 7 sections, calculate corresponding delay time according to above algorithm, when reaching 90%, transient current begins to start this algorithm.
The inverse time lag relation of table 1 loop back roll current of electric and time
| The load percentage value | 90% | 100% | 110% | 120% | 130% | 140% | 150% |
| The corresponding delay time | 1m | 48s | 40s | 33s | 28s | 24s | 21s |
Upper table can be expressed as:
When the loop back roll load〉90% also lasting 1m, then report to the police
When the loop back roll load〉100% also lasting 48s, then report to the police
When the loop back roll load〉110% also lasting 40s, then report to the police
When the loop back roll load〉120% also lasting 33s, then report to the police
When the loop back roll load〉130% also lasting 28s, then report to the police
When the loop back roll load〉140% also lasting 24s, then report to the police
When the loop back roll load〉150% also lasting 21s, then report to the police.
Claims (1)
1. the method that rolling mill production line loop back roll motor instantaneous overload is reported to the police is characterized in that,
Step 1, time t reduces with the current i increase during according to overload, determines that time and current relationship meet following formula:
Delay time t=K/ (i when electric current is i
n-1);
K=80 wherein; N=2;
Step 2 with current of electric momentary load 90% and 150% difference substitution following formula, by following formula, draws the minimax delay time and is respectively: t1=1m, t2=21s;
Step 3 is divided into seven sections with delay time length, calculates corresponding delay time according to above algorithm, and when transient current reached load 90%, beginning was calculated the t value according to following formula, judges whether to report to the police according to t value size:
When the loop back roll load〉90% also lasting 1m, then report to the police
When the loop back roll load〉100% also lasting 48s, then report to the police
When the loop back roll load〉110% also lasting 40s, then report to the police
When the loop back roll load〉120% also lasting 33s, then report to the police
When the loop back roll load〉130% also lasting 28s, then report to the police
When the loop back roll load〉140% also lasting 24s, then report to the police
When the loop back roll load〉150% also lasting 21s, then report to the police.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110272512XA CN103001185A (en) | 2011-09-15 | 2011-09-15 | Warning method for instantaneous overload of cold rolling production line looper motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110272512XA CN103001185A (en) | 2011-09-15 | 2011-09-15 | Warning method for instantaneous overload of cold rolling production line looper motor |
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| CN103001185A true CN103001185A (en) | 2013-03-27 |
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| CN201110272512XA Pending CN103001185A (en) | 2011-09-15 | 2011-09-15 | Warning method for instantaneous overload of cold rolling production line looper motor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104550253A (en) * | 2013-10-22 | 2015-04-29 | 上海宝钢工业技术服务有限公司 | Pre-warning system and pre-warning method for inclination of temper mill |
| CN111338301A (en) * | 2020-02-28 | 2020-06-26 | 鞍钢股份有限公司 | Method for preventing stalling and tipping of vertical loop of aluminum-zinc plating unit |
| CN113705854A (en) * | 2021-07-13 | 2021-11-26 | 上海烟草集团有限责任公司 | Fan current abnormity monitoring and early warning method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN2548342Y (en) * | 2002-05-14 | 2003-04-30 | 叶长春 | Fireproof leakage current acting alarm device |
| CN102074932A (en) * | 2011-01-06 | 2011-05-25 | 广东省韶关钢铁集团有限公司 | Method and system for monitoring motor load |
| US20110156680A1 (en) * | 2009-12-25 | 2011-06-30 | Wen-Chung Yeh | Methods and related controllers for controlling output power of a power supply |
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2011
- 2011-09-15 CN CN201110272512XA patent/CN103001185A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2548342Y (en) * | 2002-05-14 | 2003-04-30 | 叶长春 | Fireproof leakage current acting alarm device |
| US20110156680A1 (en) * | 2009-12-25 | 2011-06-30 | Wen-Chung Yeh | Methods and related controllers for controlling output power of a power supply |
| CN102074932A (en) * | 2011-01-06 | 2011-05-25 | 广东省韶关钢铁集团有限公司 | Method and system for monitoring motor load |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104550253A (en) * | 2013-10-22 | 2015-04-29 | 上海宝钢工业技术服务有限公司 | Pre-warning system and pre-warning method for inclination of temper mill |
| CN111338301A (en) * | 2020-02-28 | 2020-06-26 | 鞍钢股份有限公司 | Method for preventing stalling and tipping of vertical loop of aluminum-zinc plating unit |
| CN111338301B (en) * | 2020-02-28 | 2023-03-03 | 鞍钢股份有限公司 | Method for preventing stalling and tipping of vertical loop of aluminum-zinc plating unit |
| CN113705854A (en) * | 2021-07-13 | 2021-11-26 | 上海烟草集团有限责任公司 | Fan current abnormity monitoring and early warning method |
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Application publication date: 20130327 |