Rope diameter reduction

  • Causes

Reduction of the ropes diameter due to mechanical abrasion of ropes against the drive sheave

  • Description of defect

Wearing of ropes can cause reduction in rope diameter causing inadequate strength of the ropes. Ropes that have contact with wearing drive sheave grooves will have full contact with the surface of the sheave groove hence greater pressure is exerted on the ropes and sheave grooves. This condition will promote the greatest amount of rope abrasion and eventually reducing the ropes diameter.

the-end-of-the-suspension-ropes-are-broken-ropes

The end of the suspension ropes are broken ropes [16]

 

  • Diagnostic/testing method

Gauge is used to measure the diameter of the ropes, taken on a straight portion of rope at worst location. Measurement shall be taken twice at the same position at right angles and if the diameter is below the replacement value, ropes shall be replaced. If only one measurement below the replacement value, criteria for wire breaks shall be referred. If the ropes fit in the outer stepped slot and no sign of rouge, the ropes are in acceptable condition.

ropes-require-replacement-as-there-is-presence-of-rouge-30

Ropes require replacement as there is presence of rouge [30]

ropes-require-replacement-as-it-fits-in-inner-stepped-slot-bottom-of-slot-30

Ropes require replacement as it fits in inner stepped slot (bottom of slot) [30]

 

  • Good practices

The condition, type, number and diameter of the hoisting ropes shall be inspected while cut off the power. With power on, the hoisting ropes shall be inspected for visual defects.

Spring balance or other suitable equipment shall be used to ensure the governor ropes are properly and equally tensioned (SS550). The conditions of the ropes need to be properly inspected to detect any signs of wearing and reduction of ropes diameter.

The diameter of any remaining ropes shall not be less than the nominal diameter minus 0.4 mm (0.015 in.). Measurement of ropes diameter shall be done from crown to crown, as the crown wires subject to wear that can reduced the rope diameter and the breaks that occur in the wear area.

 

  • Corrections

If one rope of a strand is worn or damaged and require to be replaced, the entire strands shall be replaced, except when the damaged occur during installation where the ropes passed the testing prior to being subjected to elevator service, it shall be permissible to replace one damaged rope with a new rope (ASMEA17.1-2010).