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Minimizing Rope Wear
With our overload measurement systems rope wear can be minimized considerably. With a few simple steps the rope life can be extended by many years. And best of all, the necessary functions are already integrated into our overload measurement systems at no extra cost.Whether high-performance system or standard lift, plastic (rubber) coated or not, the ropes were and are one of the most important components of lifts which also contribute significantly to the maintenance costs. This applies especially, if the ropes unnecessarily wear disproportionately fast. The problems are often caused by the construction of the facility which hardly can be changed afterwards. Fortunately, there are some ways, even for existing installations, to produce the optimum in terms of minimizing the rope wear.
The Problem
The problem of excessive rope wear increasingly occurs since the trend in the elevator market has gone towards ever thinner ropes. Triggered by the demand for elevator systems with minimal space requirements and the increasingly tough cost pressures, the drives are getting smaller and more compact at the same time increasing engine speed and decreasing engine torque. Lower engine torque and higher engine speeds require traction sheaves with relatively small diameters. Inevitably, the suspension ropes have to be thin in order to ensure the correct ratio of drive sheave diameter to rope diameter (D / d). To ensure sufficient rope security and a high load capacity, the number of ropes and the suspension ratio is increased. New systems with 12 or even 14 carrying ropes and strong reduction ratios are now an integral part of the elevator market. As the rope research shows, the bending capacity of ropes decreases steadily with the diameter. A smaller ratio of drive sheave diameter to rope diameter (D / d) reduces the bending capacity as well as multiple deflections of the ropes.Uniform Adjustment of Rope Tensions
Anyone who has ever adjusted a set of ropes knows, how difficult a task this can be. As changing the tension of one rope causes directly a change of the tension of all the other ropes of the set, the setting of a group of four ropes is relatively difficult job and requires some time, even if you can measure the tension of each rope with a metering device. The human brain is only capable at solving the problem by trial and error, so each rope has to be tensioned or relaxed (often several times) in small increments. For a set of up to twelve ropes this procedure takes considerable time to complete.
But the correct setting is so extremely important! The difference in rope live between a set of ropes adjusted relatively uniform (max. 10% deviation of the ropes tensions) to the same set of ropes with a deviation of up to 25% deviation may be as much as 38%!
A set of ropes which could perform its duties for up to 10 years will have to be replaced after 6 years.
But the correct setting is so extremely important! The difference in rope live between a set of ropes adjusted relatively uniform (max. 10% deviation of the ropes tensions) to the same set of ropes with a deviation of up to 25% deviation may be as much as 38%!
A set of ropes which could perform its duties for up to 10 years will have to be replaced after 6 years.
The Solution
Free Rope-Adjusting Software
With our free software (see below) each AE12 overload measuring device is equipped for quick and easy adjustment of the support means. This can prevent unnecessary wear on the ropes. Even with a deviation of only 20% of tension between the ropes, the rope service life will almost be halved. A good rope setting and regular monitoring thus helps greatly with saving costs. In the software, a rope compensation wizard may be utilized, which has been parameterized with preset tolerances between the rope tensions.
As soon as the rope compensation wizard has been started, the percentage deviation from the ideal rope load for each suspension element is shown via a colored bar. A bar above the center line means, that the supporting mean in question bears too much load, a bar below the center line stands for a rope which has not been tensioned enough. If the rope has been set within the desired tolerance, the color of the bar changes from red to green.
With the rope tension wizard each support mean has to be set only once.
As soon as the rope compensation wizard has been started, the percentage deviation from the ideal rope load for each suspension element is shown via a colored bar. A bar above the center line means, that the supporting mean in question bears too much load, a bar below the center line stands for a rope which has not been tensioned enough. If the rope has been set within the desired tolerance, the color of the bar changes from red to green.
With the rope tension wizard each support mean has to be set only once.
Monitoring is important
Since its first version our overload measuring device AE12 has had an additional relay output, which gives a signal when the rope loads vary too much. The maximum allowable deviation of the ropes to each other may be defined by user. If a monitoring system is available at the elevator, the signal may be forwarded, but a look at the status LED for the signal during regular maintenance of the elevator is sufficient to counteract unnecessary rope wear in time.
You will find the latest software for the use of rope tension wizard AE12 units with firmware version V 1.24 here:
For older firmware versions (<V 1.24) the right software can be found here:
22.07.2016
