GRAVITY DRIVEN START PHASE IN POWER LIMITED ELEVATOR RESCUE OPERATION
First Claim
1. A method of performing an elevator rescue run using power from a backup power source when main power is interrupted, the method comprising:
- holding an elevator car in position with a brake;
initiating a rescue run by lifting the brake to allow the car to move by gravity;
sensing movement of the car;
if the car is not moving, supplying backup power to the motor to apply motor torque to drive the car in a selected direction during the rescue run; and
if the car is moving, supplying backup power to the motor to produce a motor torque synchronized with sensed movement of the car during the rescue run in a direction of sensed movement.
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Accused Products
Abstract
When main power to an elevator system 10 is lost, an automatic rescue operation is performed using power from a backup power source 46. A rescue run for an elevator stopped between floors is initiated by lifting a brake 28 and allowing the elevator car 12 to move by gravity. If the car 12 moves as a result of a weight imbalance between the car 12 and a counterweight 14, operation of the hoist motor 24 is synchronized with sensed movement of the car 12 to generate electricity. If weight is balanced so that the car 12 does not move, backup power is supplied to the hoist motor 24 to apply a motor torque to drive the car 12 in a selected direction during the rescue run.
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Citations
20 Claims
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1. A method of performing an elevator rescue run using power from a backup power source when main power is interrupted, the method comprising:
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holding an elevator car in position with a brake; initiating a rescue run by lifting the brake to allow the car to move by gravity; sensing movement of the car; if the car is not moving, supplying backup power to the motor to apply motor torque to drive the car in a selected direction during the rescue run; and if the car is moving, supplying backup power to the motor to produce a motor torque synchronized with sensed movement of the car during the rescue run in a direction of sensed movement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An elevator system comprising:
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an elevator car; a counterweight; a sheave; roping suspending the car and the counterweight and extending over the sheave; a hoist motor having a shaft connected to the sheave; a sensor for providing a signal representative of motion of the elevator car; a brake for preventing rotation of the shaft; a power management system for detecting when main power is lost and providing backup power; a drive for controlling operation of the hoist motor;
wherein the drive, in response to a loss of main power, initiates an automatic rescue run by lifting the brake to allow the elevator car to move by gravity, applies motor torque to operate the hoist motor as a generator while the elevator car moves by gravity during the rescue run, and applies motor torque to operate the hoist motor as a motor to drive the elevator car if the elevator car is unable to move by gravity during the rescue run. - View Dependent Claims (10, 11, 12, 13)
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14. A method of performing an elevator rescue run, the method comprising:
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sensing an interruption of main power that has caused an elevator car to be held in position with a brake; initiating a rescue run by lifting the brake to allow the car to move by gravity; sensing movement of the car; if the car does not move by gravity, supplying backup power from a backup power source to the motor to apply motor torque to drive the car in a selected direction during the rescue run; and if the car is moves by gravity, supplying backup power to the motor to produce a motor torque synchronized with sensed movement of the car during the rescue run in a direction of sensed movement. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification