1. A tree tensile load indicating belt device, having
a belt (10) with a loop at each end (12, 12\u2032) which loop is formed by turning over the end parts of the belt (10) and fastening the ends to the belt via fastenings (14, 14\u2032), wherein the fastenings (14, 14\u2032) and the belt (10) are adapted to withstand a predetermined minimum tensile force, said belt being a first color, and
an indicating element (16) having a signalling colour different from said first color in the vicinity of at least one of the loops (12), which indicating element is fastened with fastenings (18, 18\u2032) at first and second end portions of the signalling element onto the belt (10) such that said indicating element (16) shortens the belt (10), wherein the load carrying capacity of the fastenings (18, 18\u2032) is different, wherein the first indicating element end fastening (18) is a rated breaking point which yields to a pre-determined load, while the second indicating element end fastening (18\u2032) withstands higher loads such that the first indicating element end fastening (18) gives way when a pre-determined tensile force acts on the belt (10), the tensile force being smaller than said minimum tensile force which the loop fastenings (14, 14\u2032) and the belt are adapted to withstand, whereby the indicating element (16), released at one end and attached at the other end, forms a signal pendant different in color from said first color, wherein one end of said belt device is secured to a tree part to be monitored, and the other end of said belt device is secured to a tree part stronger than the tree part to be monitored.
2. The belt device according to claim 1, wherein the belt (10) is enclosed loosely between the 1oops (12, 12\u2032) by an opaque protective tube (17), which also covers the indicating element (16) in the state in which both its ends are fastened.
3. The belt device according to claim 2, wherein the indicating element (16) projects beyond the opaque protective tube (17) at least partially after its fastening (18) has given way when the tensile force has exceeded the limit.
4. The belt device according to claim 1, wherein the fastening (18) which is distant to the loop gives way when the pre-determined tensile force is exceeded.
5. The belt device according to claim 1, wherein a region (20) of the belt (10) which is overlapped by the indicating element (16) is folded in a Z-shaped manner.
6. The belt device according to claim 1, wherein the belt (10) is made of a plastic material.
7. The belt device according to claim 6, wherein the plastic material is a polyester-, polyamide- or polyethylene fabric.
8. The belt device according to claim 1, wherein the indicating element (16) is made of a plastic material.
9. The belt device according to claim 8, wherein the plastic material is a polyester-, polyamide- or polyethylene fabric.
10. The belt device according to claim 1, wherein the indicating element (16) is yellow, orange or red.
11. The belt device according to claim 1, wherein the fastening (14, 14\u2032) of the end portions of the belt (10) which forms the loop (12, 12\u2032) is a seam.
12. The belt device according to claim 1, wherein the fastening of the end portions of the belt (10) which forms the loop (12, 12\u2032) is by plastic welding, by means of an adhesive or by riveting.
13. The belt device according to claim 1, wherein the fastening (18, 18\u2032) of the end portions of the indicating element (16) on the belt (10) is by a seam.
14. The belt device according to claim 1, wherein the fastening of the end portions of the indicating element (16) on the belt (10) is by plastic welding, by means of an adhesive or by riveting.
15. The belt device according to claim 1, wherein the tensile force leading to giving way of the fastening (18) of the end portion of the indicating element (16) on the belt (10) is in the range of 5 kN to 100 kN.
16. A tree tension device with overload indication, including
a chain, rope or belt tension organ (10), at the ends of which a tensile force acts, and
at least one indicating element (16) having a signalling colour different from the tension organ (10) color which indicating element (16) when released visually signals a tensile force which exceeds a pre-determined tensile force,
wherein the tension organ (10) is enclosed by an opaque protective tube (17) which covers at least the indicating element (16), and
wherein the indicating element (16) is fastened with two end portions on the tension organ (10) and overlaps the tension organ in the length direction, forming a loop part (20) which shortens the tension organ, the indicating element (16) having a signalling colour, which indicating element is fastened with fastenings (18, 18\u2032) at first and second end portions of the signalling element onto the tension organ (10) such that said indicating element (16) shortens the tension organ (10), wherein the load carrying capacity of the fastenings (18, 18\u2032) is different, wherein the first indicating element end fastening (18) is a rated breaking point which yields to a pre-determined load, while the second indicating element end fastening (18\u2032) withstands higher loads such that the first indicating element end fastening (18) gives way when a pre-determined tensile force acts on the tension organ (10), the tensile force being smaller than said minimum tensile force which the loop fastenings (14, 14\u2032) and the belt are adapted to withstand, whereby the indicating element (16), released at one end and attached at the other end, forms a signal pendant wherein one end of said tension device is secured to a tree part to be monitored, and the other end of said tension device is secured to a tree part stronger than the tree part to be monitored.
17. The tension device according to claim 16, wherein the first fastening (18) of the indicating element (16) on the tension organ (10) gives way when a predetermined tensile force is exceeded and at least a portion of the indicating element (16) is pulled out from the opaque protective tube (17) by the straightening of the loop part (20) of the tension organ (10).
18. A tree tensile load indicating method for quickly and reliably determining from a distance whether an overload has occurred on a belt device, the method comprising:
forming a belt (10) with a loop at each end (12, 12\u2032) which loop is formed by turning over the end parts of the belt (10) and fastening the ends to the belt via fastenings (14, 14\u2032), wherein the fastenings (14, 14\u2032) and the belt (10) are adapted to withstand a predetermined minimum tensile force, said belt being a first color,
providing said belt with an indicating element (16) having a signalling colour different from said first color in the vicinity of at least one of the loops (12), which indicating element is fastened with fastenings (18, 18\u2032) at first and second end portions of the signalling element onto the belt (10) such that said indicating element (16) shortens the belt (10), wherein the load carrying capacity of the fastenings (18, 18\u2032) is different, wherein the first indicating element end fastening (18) is a rated breaking point which yields to a pre-determined load, while the second indicating element end fastening (18\u2032) withstands higher loads such that the first indicating element end fastening (18) gives way when a pre-determined tensile force acts on the belt (10), the tensile force being smaller than said minimum tensile force which the 1oop fastenings (14, 14\u2032) and the belt are adapted to withstand,
attaching said first loop to a tree part to be monitored, attaching said second loop to a tree part stronger than the tree part to be monitored,
observing whether a signal pendant different in color from said first color has been released by the indicating element (16) becoming released at one end while remaining attached at the other end, the signal pendant indicating that overload has occurred on a belt device.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for use in correcting a signal from a tachometer coupled to a rotating shaft in a wind turbine, said method comprising:
receiving a raw tachometer signal from the tachometer, the signal indicating the speed andor angular position of the shaft, wherein the tachometer is configured to transmit at least 1000 pulses in each revolution of the shaft;
dividing each revolution of the received raw signal into a predetermined number of segments, wherein each segment is associated with an angular portion of the shaft;
determining a speed profile by tracking the received raw signal, the speed profile including a speed of each segment for each revolution;
determining a cyclic error exists in the raw tachometer signal; and
providing a corrective signal to adjust a torque within the wind turbine based at least in part on the determined cyclic error.
2. A method in accordance with claim 1, wherein determining a speed profile further comprises tracking the received raw signal for at least one of a predetermined period of time and a predetermined number of revolutions.
3. A method in accordance with claim 1, further comprising determining an average segment speed for each revolution.
4. A method in accordance with claim 3, further comprising determining a segment error by comparing a speed of a segment of a revolution to the average segment speed of the revolution.
5. A method in accordance with claim 4, further comprising determining an average segment error for each segment by averaging the segment errors of the segment for at least one of a predetermined period of time and a predetermined number of revolutions.
6. A method in accordance with claim 5, wherein determining a cyclic error exists comprises comparing the average segment error to a predetermined threshold.
7. A method in accordance with claim 5, wherein providing a corrective signal comprises subtracting the average segment error from the received raw signal.
8. A method in accordance with claim 1, further comprising determining an angular position profile by tracking the received raw signal, the angular position profile including an angular position of each segment for each revolution.
9. A method in accordance with claim 8, wherein determining a cyclic error exists comprises comparing an angular position of a segment of a first revolution to an angular position of the segment of a second revolution.
10. A wind turbine system comprising:
a tachometer configured to provide a raw tachometer signal, the signal indicating a number of revolutions of a shaft of the wind turbine, wherein the tachometer is further configured to transmit at least 1000 pulses in each revolution of the shaft; and
a power converter configured to:
divide each revolution of the received raw signal into a predetermined number of segments, wherein each segment is associated with an angular portion of the shaft;
determine a speed profile by tracking the received raw signal, the speed profile including a speed of each segment for each revolution for at least one of a predetermined period of time and a predetermined number of revolutions;
determine a cyclic error exists in the raw tachometer signal; and
provide a corrective signal to adjust a torque within the wind turbine using the determined cyclic error.
11. A wind turbine system in accordance with claim 10, wherein the power converter is further configured to
determine an average segment speed for each revolution for at least one of a predetermined period of time and a predetermined number of revolutions.
12. A wind turbine system in accordance with claim 11, wherein the power converter is further configured to:
determine a segment error by comparing a speed of a segment of a revolution to an average segment speed of the revolution;
determine an average segment error by averaging the segment errors of a segment for at least one of a predetermined period of time and a predetermined number of revolutions; and
compare the average segment error to a predetermined threshold.
13. A wind turbine system in accordance with claim 12, wherein the power converter is further configured to provide a corrective signal by subtracting the average segment error from the received raw signal.