Elevator system using dynamic braking

Patent metadata

Field	Value
Publication number	US-9975729-B2
Application number	US-201214422775-A
Country	US
Kind code	B2
Filing date	Aug 22, 2012
Priority date	Aug 22, 2012
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

An elevator system includes a motor having a plurality of motor windings; a plurality of braking switches coupled to the motor windings, the braking switches coupling the motor windings to a common electrical point; a sensor coupled to the motor, the sensor providing a sensed signal indicative of a parameter of the motor; and a controller providing a braking signal to the braking switches in response to the sensed signal to selectively control the braking switches to short the motor windings.

First claim

The invention claimed is:

1. A system comprising:
a motor having a plurality of motor windings;
a plurality of braking switches coupled to the motor windings, the braking switches coupling the motor windings to a common electrical point;
a sensor coupled to the motor, the sensor providing a sensed signal indicative of a parameter of the motor; and
a controller providing a braking signal to the braking switches in response to the sensed signal to selectively control the braking switches to short the motor windings;
wherein the controller compares the sensed signal to a threshold and generates the braking signal in response the sensed signal exceeding the threshold.

2. The system of claim 1 wherein the braking switches couple the motor windings in a star configuration.

3. The system of claim 1 wherein the braking switches are transistors.

4. The system of claim 3 wherein the braking switches are MOSFETs.

5. The system of claim 1 wherein the sensed signal represents current at the motor.

6. The system of claim 1 wherein the sensed signal represents speed at the motor.

7. The system of claim 1 wherein the sensed signal represents current and speed at the motor.

8. The system of claim 1 wherein the controller determines if the elevator system is in maintenance mode, and provides the braking signal only when the elevator system is in maintenance mode.

9. A method for providing dynamic braking in an elevator system, the method comprising:
sensing a parameter of a motor;
determining an operating mode of the elevator system; and
selectively shorting windings of the motor to a common electrical point in response to sensing the parameter and determining the operating mode of the elevator system;
wherein selectively shorting windings of the motor comprises comparing the parameter to a threshold and selectively shorting windings of the motor to the common electrical point in response to the parameter exceeding the threshold.

10. The method of claim 9 wherein sensing the parameter of the motor includes sensing current at the motor.

11. The method of claim 9 wherein sensing the parameter of the motor includes sensing speed at the motor.

12. The method of claim 9 wherein sensing the parameter of the motor includes sensing current at the motor and speed at the motor.

13. The elevator system of claim 9 wherein the controller determines if the system is in maintenance mode, and provides the braking signal only when the system is in maintenance mode.

14. An elevator system comprising:
a motor having a plurality of motor windings;
a plurality of braking switches coupled to the motor windings, the braking switches coupling the motor windings to a common electrical point; and
a controller providing a braking signal to the braking switches in response to the system being in a maintenance mode and a mechanical brake applied;
wherein the controller determines if the system is in maintenance mode, and provides the braking signal only when the system is in maintenance mode.

Assignees

• Rogers Kyle W
• Marvin Daryl J
• Otis Elevator Co

Inventors

• Rogers Kyle W
• Marvin Daryl J

Classifications

• G01P3/44

  for measuring angular speed (G01P3/56 takes precedence) · CPC title

• H02P3/22

  by short-circuit or resistive braking · CPC title

• B66B1/308

  with AC powered elevator drive · CPC title

• B66B5/0043

  Devices enhancing safety during maintenance · CPC title

• B66B1/32

  effective on braking devices {, e.g. acting on electrically controlled brakes (brake control H02P, lift brakes per se B66B5/02)} · CPC title