Traction Problem Otis 269HT : LUSENET : Elevator Problem Discussion : One Thread

I am have a 269HT that slips pretty bad, on the order of 2 to 4 feet. (36" sheave, double wrapped) We re-roped and had the sheave re-grooved, lubricated and re-tensioned the ropes, but it keeps on slipping. I watched it with a strobe and I can see that the sheave is slowing down and speeding up mid-run, but I'm not sure that's causing the slip or is a symptom of the slip. The drive is a magentek and the tachometer is a Dynapar. I am thinking of checking to see if the counterweight is properly weighted for the car. Any suggestions?

-- Rick Owens (, March 24, 2004


What type of roping you have?

-- (, March 24, 2004.

I have Pfiefer-Draco 6-25 fiber core high speed traction steel. Yes, it slips in both directions. The problem is more pronounced at the 19th floor, the building is 34 stories.

-- Rick Owens (, March 24, 2004.

The Pfiefer-Draco rep was out and recommended we use Vita-life 600.

-- Rick Owens (, March 24, 2004.

Roping is 1:1, with comp ropes.

-- Rick Owens (, March 24, 2004.

We did replace the tachometer, but not the encoder. I 'll try that next. Both are retrofitted to the machine and I'm not very confident about that mounting. The shaft that turns them both was threaded into the motor shaft and it does not turn true, but there are flex couplings. The encoders bodies are mounted on 1/4" all-thread rod standing off of the end of the motor.

-- Rick Owens (, March 24, 2004.


Isn't rope slippage a leveling speed! Try sonstrac it helped on B vernieer jobs. The ropes should not slip on ocillation unless severe. If they slip on minor ocillation i wonder how bad it slips on acc or jerk with aload.

-- (KANTHACKJ@AOL.COM), April 08, 2004.

If the vibration seems bad with the car at mid hatch, double check parameters 104, 105,107 and 108 on the drive. With magnateck dsd412 they'll vibrate bad with the wrong settings

-- W (, March 24, 2004.


At the risk of sounding stupid I pose a few questions. First is what type of control system is operating this elevator and drive?

Is the control system reporting any faults?

Have you considered that the control system is recognizing a fault and shutting down the drive and recovering from said error creating a slide condition?

Encoders and Tachometers would not normally create a slip condition yet drive/control faults will.

Sounds to me like you are having a control failure at the 19th floor be it an interlock or traveling cable issue is yet to be determined.

Provide us with control info and it may make it easier to pin down.


-- Wilbur (, March 24, 2004.

Hi Rick I have worked on 1600 fpm 269HT jobs that slipped and other guys used to use fuller earth on the ropes to help the traction slipage problem its a kind of powder, that was over twenty years ago and that was then and today is a brave new world and before you do that check with your supervisor about doing that. Also another thing I would do is get a white paint pen and mark a 1/8 line accross the ropes and also mark the sheave with the line and run the car full speed top to bottom and back and measure how much slip on a normal run. I would also maybe call Bethlem Wire rope and talk to those guys and make sure you have the correct ropes. I still have pictures of me in front of the 369ht machines at the trade center, 116 stops, 17 foot high 104 selector and 3600 feet of selector tape, now thats an elevator.

-- Jim (ELEVATOR555@HOTMAIL.COM), March 25, 2004.

I have had a similar problems but with fault codes on the drive of modernization jobs, one that took me a while was an intermittent fault caused by the comp rope sheave bearing catching, I kept the auto lubes full but years of past neglect had caused shavings to clog lines, depending on what governor you have, are set screws tight sometimes theres more than one from the sheave to the position encoder and make sure couplings are not broken.

-- Mike Underwood (, March 26, 2004.


The the original data tag on the crosshead call for a 6 by 25 hoistrope. Is it possible that the new rope is metric and the grooves were cut for Imperial ropes? Metric ropes are just a friction smaller. I too, would like to know if if you have excessive creepage when the elevator is run from top to bottom one complete round trip, with a chalk line drawn acroos the sheave and cables at the beginning of a run. Anything in excess of 2 inches is excessive creepage.

-- Don Rosenberger (, March 29, 2004.

In your testing have you tried balanced and full load conditions to check for any change in conditions to check for any balance problems?

-- mole (, March 31, 2004.

Another thing to consider is the type of rope, Regular or Lang lay I don't recall any 269 machines with sheave liners but those require lang lay ropes cast sheave groove uses regular lay. Regular lay on sheave liners will slip badly. Just throwing 2 cents in the pot. Tom

-- T. LaRue (, July 20, 2004.

Had a similar fault last year. Ropes slipped midshaft.Fault found to ba a really tightspot in counterweight guides hidden behind the mid- shaft safety screen.Possibly worth a look

-- geoff judge (, July 22, 2004.

Moderation questions? read the FAQ