Method and test system for testing failure of a machinery brake of an elevator based on elevator machine oscillation

Abstract

The purpose of the invention is to detect a failure situation wherein the machinery brake of an elevator does not open sufficiently. In the method for testing failure of a machinery brake of an elevator, the machinery brake is controlled to open. After this, the traction sheave is oscillated with a test torque, the movement of the elevator machine is measured in connection with the oscillation, and if the machine does not move in connection with the oscillation, it is deduced that the machinery brake has not opened and has therefore failed.

Claims

1. Method for testing failure of a machinery brake of an elevator, wherein in the method: the machinery brake is controlled to open; after this, the traction sheave is oscillated with a test torque; the movement of the elevator machine is measured in connection with the oscillation; if the machine does not move in connection with the oscillation, it is deduced that the machinery brake has not opened and has therefore failed.

2. Method according to claim 1, wherein a shorter time is selected as the oscillation time than the time according to the displacement function of the elevator mechanics for transmitting movement of the traction sheave into movement of the elevator car.

3. Method according to claim 1, which is performed in the control of an elevator.

4. Method according to claim 1, wherein when it is deduced that the machinery brake has failed, a fault code is formed and the elevator is shut out of use.

5. Method according to claim 1, which is used when the elevator car is stationary.

6. Method according to claim 5, which is used when the elevator is in normal operation.

7. Test system for testing failure of a machinery brake of an elevator, wherein the test system comprises: a control means of the machinery brake for controlling the machinery brake to open; a control means of the machine, which means is configured to oscillate the traction sheave with a test torque after the control means of the machinery brake has controlled the machinery brake to open; a measuring means, which is configured to measure the movement of the elevator machine in connection with the oscillation; and a logic, which is configured to analyze the measurement results of the measuring means that are obtained in connection with the oscillation and to make the deduction that the machinery brake has not opened and has therefore failed if the machine does not move in connection with the oscillation.

8. Test system according to claim 7, wherein a shorter time is selected as the oscillation time than the time according to the displacement function of the elevator mechanics for transmitting movement of the traction sheave into movement of the elevator car.

9. Test system according to claim 7, which is integrated into the control of the elevator.

10. Test system according to claim 7, which is configured to form a fault code for shutting the elevator out of use when the logic has deduced that the machinery brake has failed.

11. Test system according to claim 7, which is used when the elevator car is stationary.

12. Test system according to claim 11, which is used when the elevator is in normal operation.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The FIGURE illustrates an elevator in accordance with example embodiments.

DETAILED DESCRIPTION

(2) An elevator 1 that comprises a control/test system 10 according to the invention and in which the method according to the invention is used has an elevator car 20, which is driven with the hoisting machine of the elevator 1 by means of traction ropes traveling via the traction sheave 30 of the hoisting machine. The elevator 1 also comprises an electromechanical machinery brake 40, which engages with the traction sheave 30 or with the shaft of the hoisting machine to brake the traction sheave 30 and thus also the movement of the elevator car 20.

(3) The electromechanical machinery brake 40 of the elevator 1 might be damaged if it does not open properly. The idea of the invention is to observe the braking torque produced by the brake utilizing a dynamic model of the elevator and of the machine.

(4) The torque of the machinery brake 40 braking the machine can be measured e.g. when the elevator car 1 is stationary by rapidly oscillating the traction sheave 30. When the oscillation is sufficiently rapid, it is not noticed in the elevator car 1. The braking moment can also be isolated from the run-time behavior between the elevator car 1 and the traction sheave 30.

(5) If the machinery brake 40 does not open properly, the increased friction is detected and the necessary procedures, such as fault codes and shutting the elevator 1 out of use can be executed.

(6) The European Committee for Standardization (French: Comite Europeen de Normalisation) is currently preparing a new European Standard EN81-20 that is intended to replace European Standard EN81-1.

(7) In connection with this, one working group was assigned to review the European Standard EN60204-1 to see which points of it are applicable to elevators. Clause 9.3.4 of the European Standard EN60204-1 requires that where a failure of a mechanical brake drive can result in a machinery brake being applied when the machinery of the elevator machine is energized and a hazardous situation can result as a consequence, the elevator shall be provided with a prevention system to switch off the machinery of the elevator machine

(8) The method and test system presented here for testing insufficient opening of a machinery brake of an elevator thus enable compliance with the requirements of Clause 9.3.4 of the European Standard EN60204-1. It is possible also that by means of the invention the requirements also of European Standards EN80-20 and prEN 81-20:2011-11 can be complied with better.

(9) The invention must not be regarded as being limited only to the claims below but instead should be understood to include all legal equivalents of said claims and combinations of the embodiments presented.