Elevator Troubleshooting & Repair. David Herres

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СКАЧАТЬ and DC Electric Motor Maintenance, VFD Troubleshooting, and Diagnostic Procedures

Good Motor Maintenance

       Machine Room

       Bearings

       Motor Shaft and Bearing Current

       Vibration Analysis

       Motor Drive Alignment

       Electrical Issues

       Diagnosing Three-Phase Circuits and Motors

       Testing Components

       Study Questions

       CHAPTER 4

       Advanced Motor Repair

       What It Takes

       Some Examples

       Surge Testing

       Core-Loss Test

       Detecting and Analyzing Motor Vibration

       Bearing Maintenance

       More on Vibration Analysis

       Hydraulic Rope Equalizers

       Passenger Rescue from a Stuck Car

       Traveling Cable

       Lubrication and Oil Analysis

       Study Questions

       CHAPTER 5

       Troubleshooting Elevator Systems

       Study Questions

       CHAPTER 6

       Electrical Troubleshooting Tools and Instruments

       Test Lights

       Multimeters

       Non-Contact Meters

       Power Quality Measurements

       Oscilloscopes

       PC Based Spectrum Analyzer

       Thermal Imager

       Study Questions

       CHAPTER 7

       Measuring Power Quality: How It May Be Improved

       Three-Phase Configurations

       Total Harmonic Distortion Measurements

       Catastrophic Transformer Failure

       Costly Harmonics

       Power Factor

       What’s All This About Sine Waves?

       Three-Phase Motors

       Oscilloscope

       Fourier Transform

       Study Questions

       CHAPTER 8

       Elevator System Overview

       National Electrical Code

       Study Questions

       CHAPTER 9

       Motion Controller

       Programmable Logic Controllers

       Specific Operating Modes

       Car Top Operating Station

       Study Questions

       CHAPTER 10

       Systems Connected to Elevator Installations and How They Work in Concert

       Emergency Power

       Tests and Maintenance

       Normal Electrical System

       Wiring Methods for Elevator Shafts, Pits, and Machine Rooms

       Study Questions

       APPENDIX A

       Study Questions Answers

       APPENDIX B

       Electrical Laws and Equations

       Index

INTRODUCTION

      An appropriate subtitle for this introduction would be: DON’T GET IN OVER YOUR HEAD! Elevators move large numbers of people up and down in high-rise buildings on a daily basis and there is the potential for an accident to occur. A highly-developed system of safeguards is in place, and for this reason an elevator ride is statistically far less hazardous than crossing a street.

      Fatalities are extremely rare due to the redundant safety mechanisms, but they have occurred, some because of faulty maintenance procedures. A documented instance involved two wires which were temporarily disconnected from a circuit board and then reversed, thus disabling the door interlock, which prevents an elevator car from moving when the door is not closed and latched. A child was crushed between the car floor and door opening. There are tremendous moral and legal issues, and it is the responsibility of each worker to understand the consequences of any errors.

      In the popular imagination, if an elevator cable breaks, the car immediately falls to the bottom of the shaft, killing the occupants. In actuality, the car is connected by multiple cables, which are regularly inspected for wear, any one of which would hold a fully-loaded car. Additionally, elevator cars have mechanisms known as safeties, which clamp onto the guide rails in an overspeeding or slack-cable situation.

      In performing elevator maintenance and repair, there are enormous moral and legal issues. Workers need to fully understand proper maintenance procedures so that all safeguards remain in effect. As a start, it is essential to become aware of applicable regulations and to comply with them.

      Of course, a major aspect in elevator technology is electrical. The National Electrical Code (NEC), revised and issued every three years by the National СКАЧАТЬ