Elevator Rescue Apparatus Torque Control
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Solution Overview
Problem
Existing elevator rescue operation apparatuses consume storage batteries rapidly due to high reactive current supply when the car and weight are balanced, as the rotor is rotated slowly by a rotary switch, leading to inefficient torque generation and prolonged rescue times.
Innovation Solution
A rescue operation apparatus for elevators using a permanent magnet synchronous motor with a direct current power system, featuring a brake switch, exciting means with specific excitation patterns, and a rectification means to manage current flow and torque generation, allowing efficient movement of the car even when balanced, by connecting direct current power to a three-phase winding and setting phases forward by electrical angles to maximize torque and control speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a rotary switch is used to rotate the rotor by sequential excitation, then the motor can be driven without external power, but high reactive current is supplied to the motor from the storage battery, causing rapid battery consumption
Solution Approach 1:
The patent applies preliminary action by manually rotating the rotor to a specific position before activation, where the rotor is positioned so that the magnetic pole is aligned with the winding. This preliminary positioning ensures that when power is supplied, torque is generated immediately without requiring reactive current for rotor rotation, thereby preventing rapid battery consumption while maintaining automatic operation capability
Solution Approach 2:
The patent changes the excitation parameter timing by controlling the power supply switch to activate only after the rotor reaches the predetermined position. This parameter change ensures that excitation current is supplied at the optimal moment when the rotor alignment maximizes torque efficiency, eliminating the need for continuous reactive current supply and reducing battery consumption
2Ease of operation
If the brake is released to move the car, then the car can be rescued, but when the car and weight are balanced, the car does not automatically move
Solution Approach 1:
The patent applies preliminary action by requiring manual rotation of the rotor to a predetermined position before activation. This preliminary step ensures that when the brake is released and power is supplied, the motor is already in the optimal torque-generating position, enabling immediate car movement even when balanced with the weight, thus maintaining both operational simplicity and rescue efficiency
Solution Approach 2:
The patent replaces the traditional mechanical balance-dependent movement system with an electromagnetic torque generation system. By using the permanent magnet synchronous motor's electromagnetic field to generate torque at a predetermined rotor position, the system overcomes the limitation of gravitational balance, allowing the car to move automatically upon brake release regardless of weight balance, thereby improving productivity without complicating the operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively moves the elevator car by generating maximal torque and controlling speed, reducing battery consumption and enhancing safety during rescue operations, while suppressing counter-rotation torque and allowing precise movement to the rescue floor.
Implementation Method 1
a permanent magnet synchronous motor is used for a hoist
Implementation Method 2
an exciting means that generates a torque by connecting the direct current power to a three-phase winding of the motor and making the current flow into the motor
Implementation Method 3
a brake switch that connects and opens the direct current power with a coil of the brake
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3
AI summary
It includes a brake switch (22) that connects and opens a direct current power (20) with a brake coil (24L), an exciting circuit (50) generating a torque by connecting the direct current power (20) to a three-phase winding of a motor (11) and making the current flow into the motor (11), and a rescue switch (32) that connects and opens the exciting circuit (50) with the direct current power (20). The exciting circuit (50) includes a first excitation pattern in which one electrode of the direct current power (20) is connected to one phase of the three-phase winding, and the other electrode of the direct current power (20) is connected to the other two phases of the three-phase winding, a second excitation pattern in which the phase formed by the three-phase winding of the motor (11) is set forward by an electrical angle of 90 degrees in a direction in which a car (17) is to be moved, and an off pattern in which windings of two phases are set apart from the direct current power (20).