slip of wire ropesgreenspun.com : LUSENET : Elevator Problem Discussion : One Thread
What is the exact limit for slip? How could it be tested? Is there any regulation which brings the slip of the wire ropes under a limit? Please let me know is there any code in ASME or ISO or ....
-- Siamak Jarchi (email@example.com), August 23, 2003
If it's slipping, you have a traction loss. The limit for slip that I know of is Zero, because they aren't supposed to break traction unless you have landed the car or counterweight. This is not a good thing otherwise, and could indicate you have worn sheave grooves, the wrong kind of grooves for the job (U vs. V),wrong angle on the grooves (if regrooved), groove inserts made of the wrong material or worn out (the Otis guys know what I'm talking about),wrong sheave material or diameter, wrong rope type for the sheave material and design, worn out ropes (rope diameter less than replacement diameter-A.17) excessive or incorrect lubrication (Teflon lube is a no-no), or in the event of a brake dropping at contract speed, you may be setting the brake too fast, or with more spring tension than required by the mfgr., or local codes (varies from 125-150% full load-check mfg and codes). Any of these will cause the ropes to break traction to some degree. Good Luck! S.
-- Steve (firstname.lastname@example.org), August 23, 2003.
Get heavy grid ceiling wire and make a pointer and bolt it to somewhare solid and point to and area of the sheave that is easily observed, make sure that pointer is close to sheave but doesnt touch equipment. Get a white paint pen and mark the hoist ropes and sheave with one straight 1/8 line at main landing and better yet every landing.
When the car is level so you can easily monitor rope slipage. Run the car, one run up and down and you should not slip over 1/2 inch on one run up and down on a average job, sheave to white marks on rope. You will also observe the ropes moving around indicated by the white line not sraight anymore due to ropes slipage.
If the ropes are constantly slipping individually it indicates uneven rope tension, get one of those torque wrench type rope tensioner to set. That will give you info of whats going on as regards to rope slippage. What to do then is up to the individual equipment as far as,lubing ropes, sheave and rope powdering,regroove, bigger ropes,new sheave and ropes ect. This info is from years of experiance and have never seen that tolerance referance in any code book. The old otis SOB control ran the selector off the traction driver and used a corector device to reset selector every run to bottom landing or lobby because of rope slipage and that was new equipment. Make sure all work is preformed by a certified union trained mechanics Jim
-- Jim (email@example.com), August 23, 2003.