Elevator cord health monitoring

Patent metadata

Field	Value
Publication number	US-2016002006-A1
Application number	US-201314768667-A
Country	US
Kind code	A1
Filing date	Feb 21, 2013
Priority date	Feb 21, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A method of fault detection of a belt or rope includes interconnecting a plurality of cords of the belt or rope, the cords including a plurality of wires, to form a bridge circuit. A fault detection bridge circuit is subjected to a voltage excitation and outputs a voltage which is indicative of the belt or rope damage but remaining insensitive to other environmental noises.

First claim

1 . A method of fault detection of a belt or rope comprising:
interconnecting a plurality of cords of the belt or rope, the cords including a plurality of wires, to form a bridge circuit; subjecting the bridge circuit to an excitation voltage; outputting a signal voltage from the bridge circuit, the bridge circuit structure suppressing environmental noise to increase signal to noise ratio of the signal voltage; and monitoring the signal voltage to detect a fault condition of the rope.

2 . The method of claim 1 , further comprising comparing the signal voltage to the excitation voltage in magnitude and phase to detect the fault condition of the rope.

3 . The method of claim 1 , further comprising:
comparing a profile of a measured electrical impedance to a baseline electrical impedance profile; and determining a fault condition of the belt or rope via the comparison.

4 . The method of claim 1 , wherein each leg of the bridge circuit comprises at least one cord of the belt or rope.

5 . The method of claim 4 , wherein each leg of the bridge circuit comprises two or more cords of the belt or rope.

6 . The method of claim 1 , wherein the output voltage is proportional to an impedance difference between cords of the plurality of cords.

7 . The method of claim 6 , wherein the output voltage is indicative of an impedance difference between laterally inner cords of the belt and laterally outer cords of the belt.

8 . The method of claim 1 , wherein fault conditions include wire breakage, fretting and/or birdcaging.

9 . The method of claim 1 , wherein the electrical impedance is measured substantially continuously.

10 . The method of claim 1 , further comprising switching the interconnection of the plurality of cords via a switching mechanism operably connected to the plurality of cords.

11 . The method of claim 1 , wherein the excitation voltage is supplied from an AC voltage source.

12 . The method of claim 1 , wherein at least one leg of the bridge circuit comprises a fixed resistor.

13 . The method of claim 12 , wherein two legs of the bridge circuit each comprise at least one cord and two legs of the bridge circuit each comprise a fixed resistor.

14 . An elevator system comprising:
an elevator car; one or more sheaves; a belt or rope comprising a plurality of wires arranged into a plurality of cords for supporting and/or driving the elevator car routed across the one or more sheaves and operably connected to the elevator car, the plurality of cords interconnected to form a bridge circuit.

15 . The elevator system of claim 14 , wherein each leg of the bridge circuit comprises at least one cord of the belt or rope.

16 . The elevator system of claim 15 , wherein each leg of the bridge circuit comprises two or more cords of the belt or rope.

17 . The elevator system of claim 14 , further comprising a switching element operably connected to the plurality of cords to change an interconnection configuration of the plurality of cords.

18 . The elevator system of claim 14 , further comprising an AC voltage source operably connected to the belt or rope.

19 . The elevator system of claim 14 , wherein the belt or rope is a coated belt or rope.

20 . The elevator system of claim 14 , wherein at least one leg of the bridge circuit comprises a fixed resistor.

21 . The elevator system of claim 20 , wherein two legs of the bridge circuit each comprise at least one cord and two legs of the bridge circuit each comprise a fixed resistor.

Assignees

• Otis Elevator Co

Inventors

• Sun Fanping
• Luo Xiaodong
• Mosher Daniel A
• Zhang Huan
• Wesson John P
• Chen Yan
• Thompson Mark Steven
• Kountanya Raja
• Fargo Richard N

Classifications

• G01R17/00

  Measuring arrangements involving comparison with a reference value, e.g. bridge · CPC title

• B66B9/00

  Kinds or types of lifts in, or associated with, buildings or other structures (characterised by control systems B66B1/00; apparatus for raising or lowering persons on stages of theatres A63J5/12) · CPC title

• D07B2301/307

  Breakage of wire or strand or rope · CPC title

• G01R31/12

  Testing dielectric strength or breakdown voltage {; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing (G01R31/08, G01R31/327 and G01R31/72 take precedence; measuring in plasmas G01R19/0061; measuring dielectric constants G01R27/2617; ESD, EMC or EMP testing of circuits G01R31/002)} · CPC title

• D07B2301/45

  for diagnosing · CPC title