1、Public Lessons Learned Entry: 4021 Lesson Info: Lesson Number: 4021 Lesson Date: 2010-09-29 Submitting Organization: KSC Submitted by: Annette Pitt Subject: Elevator 5-Year Test Procedure Revisions Abstract: A change to the design of a new drive installed on the high-bay elevators in the Vehicle Ass
2、embly Building (VAB) at the Kennedy Space Center caused all the elevators to fail the minimum slide-distance test. Features of the new drive design had altered system parameters. Description of Driving Event: During the 5-year-safety slide test on the high-bay elevators in the VAB, every elevator fa
3、iled the test criteria. Those criteria state that elevators must slide a certain minimum distance according to parameters stated in ASME A17.1, Safety Code for Elevators and Escalators. Elevators in the VAB were sliding short of the specified minimum distance. Lesson(s) Learned: The VABs high-bay el
4、evators were upgraded from generator-controlled to DC-drive-controlled elevators. The new units use encoders on the motors to determine the speed and position of the elevator in the hoistway. The position encoder feeds data to the programmable logic controller (PLC) about its location. When the elev
5、ator was signaled to stop during the slide test, the PLC caused the drive to start decelerating to what is termed the approach speed. It seemed the PLC was sensing a more abrupt change than was actually occurring. This effect brought the elevator to a stop sooner than intended. Adjustments to the pr
6、ocedure eliminated the unintended deceleration. Since then, every elevators 5-year safety slide test has performed within allowable scope. Recommendation(s): Whenever an elevator system is upgraded and a revalidation test is used to compare the old system to the new one, new elevator performance mus
7、t be analyzed and procedures revised to accommodate unintended deviations. Evidence of Recurrence Control Effectiveness: N/A Documents Related to Lesson: ASME A17.1, Safety Code for Elevators and Escalators Mission Directorate(s): Space Operations Additional Key Phrase(s): Ground support systems Con
8、figuration Change Control Test & Verification Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Systems analysis - cost analysis Long term sustainability and maintenance planning Engineering design and project processes and standards Additional Info: Project: Space Shuttle Program Approval Info: Approval Date: 2011-07-06 Approval Name: mbell Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
