Large-axis peristaltic detection method applicable to power station unit

[0045] Examples:

[0046] Such as Figure 1 to 3 As shown, the number of speed measuring toothed belts and the number of empty slots of the main shaft of the Three Gorges Right Bank Harbin Power Generation Unit are both 80, the length of a single toothed belt: 50mm, the length of a single slot: 110mm, and the duty cycle is 0.31. The arc length of a toothed belt plus the arc length of an empty slot corresponds to the center angle of the major shaft:

[0047] φ=360°/80=4.5°.

[0048] The angle of the center of the major axis corresponding to the arc length of a single sprocket: 4.5°*50/160=1.4°.

[0049] The angle of the center of the major axis corresponding to the arc length of a single slot:

[0050] 4.5°*110/160=3.1°.

[0051] After analysis and calculation, six probes must be installed, and the spacing of each probe is a multiple of 0.5° in order to meet the peristaltic requirements of the national standard. The identifiable domain of one cycle of the chainring is 0.5*2=1 degree (the sum of rising and falling edges), [4.5/1]+1=5, at least 5 probes are required (necessary but not sufficient conditions), after precise calculation ( Mathematical programming algorithm) 5 probes are also sufficient conditions, that is, 5 probes can meet the theoretical requirements. However, considering practical engineering problems, the six probe algorithms are more concise and easy to realize the fault-tolerant identification mechanism. At the same time, the two probes also have the function of pairing (3 pairs). Therefore, 6 probes are selected in consideration of theoretical and actual engineering requirements. As attached figure 2 Shown in the left part. In this working mode, the area covers all phases, and the logical judgment is relatively simple. considering figure 2 The position of the left part of the probe is relatively close, the probes may cause mutual interference. Therefore, the position of some probes is moved to adjacent phases by 1 to 2 cycles. Such a change does not affect the coordination relationship between the probes, but can improve the accuracy of the device and the reliability of processing. See the final probe distribution diagram figure 2 Shown in the right part.

[0052] The judgment logic of the creep alarm of the creep detection device is as follows image 3 Shown.

[0053] In the motion logic judgment of the probe, the creep angle of the unit is determined by detecting the rising and falling edges of each probe. Because each probe has a rising edge and a falling edge, there are the following 12 probe states (↑ means rising edge, ↓ means falling edge): A↑, A↓, B↑, B↓, C↑, C↓, D↑, D↓, E↑, E↓, F↑, F↓.

[0054] When the unit is stopped, the position of the probe is random, that is, the probe may fall on any phase point, so the correct action logic of the chainring must cover all phases. Investigate all positions of probe A from phase 0 to a full cycle of 4.5° (each probe is the same). If probe A meets the national standard at any position on a cycle (0-4.5°), you can It is concluded that the whole set of equipment meets the action logic requirements of the national standard. When the main shaft creeps 4.5° (one cycle), the cycle calculation restarts.