How does an elevator automatic rescue operating device ensure precise leveling and safe door opening in the event of a complete power outage?
Publish Time: 2025-11-25
Elevators, as an indispensable vertical transportation tool in modern buildings, have always had their safety as a core public concern. When the mains power suddenly fails or the control system malfunctions, causing the elevator to stop, passengers may be trapped inside the car. This is especially dangerous for the elderly, children, or those with weakened immune systems, easily leading to panic and even health risks. The elevator automatic rescue operating device was developed to address this need. This device, relying on its built-in backup power, can automatically and smoothly move the car to a preset safe floor, precisely leveling and reliably opening the car and landing doors, achieving a "rescue even without power" safety loop, even when the main power supply fails completely.1. Intelligent Energy Management: Efficient Distribution Under Limited PowerThe core of the automatic rescue device is a set of high-energy-density, maintenance-free batteries, continuously float-charged by the elevator control system during normal operation. Once a mains power outage is detected and the elevator is not leveled, the device immediately activates, prioritizing the allocation of limited power to the three most critical components: drive control, position detection, and the door operator system. Utilizing a low-power microprocessor and a high-efficiency DC-AC inverter module, the system drives the traction machine at only 10%–20% of its rated power, maximizing runtime and ensuring the completion of a full rescue operation.2. Multi-Source Position Sensing: Encoder-Free Precise PositioningTraditional elevators rely on rotary encoders to obtain the car's position, but this signal may be lost during a power outage. Advanced automatic rescue devices employ a multi-redundant positioning strategy: firstly, they read the last recorded floor information before the power outage; secondly, they use built-in Hall effect sensors or magnetic strip sensors to detect pre-installed leveling markers along the guide rails in real time; some high-end systems also integrate an inertial measurement unit to calculate the current position using acceleration and displacement integrals.3. Flexible Drive Control: Slow and Smooth Arrival at the Target FloorTo avoid passenger discomfort caused by sudden starts and stops, the rescue operation uses an "S-shaped" speed curve: during the initial acceleration phase, the speed gradually increases to 0.2–0.3 m/s, then decelerates in advance as it approaches the target floor, ultimately stopping precisely and almost silently. The entire process is controlled by a dedicated variable frequency drive module, maintaining stable torque even under low voltage conditions to prevent overshooting or undershooting due to load changes. Simultaneously, the system monitors motor current and position feedback in real time; if abnormal resistance is detected, it immediately stops operation and issues an alarm, eliminating safety hazards caused by forced operation.4. Dual Door Opening Protection: Mechanical and Electrical Coordinated UnlockingAfter leveling, the device first activates the car door operator, opening the car door; simultaneously, the landing door lock hook is released via a linkage mechanism or independent door knife. To address situations where the landing door cannot be opened due to deformation or obstruction by foreign objects, some designs are equipped with an "adaptive opening force" function—if the initial opening is obstructed, the system will briefly increase the door operator's output torque to attempt a second opening; if this still fails, a buzzer or voice prompt will guide passengers to use the emergency intercom for assistance. Furthermore, all door opening actions have time protection to prevent motor overheating, ensuring that a basic escape route can still be established even in extreme circumstances.5. Safety Logic Closed Loop: Safeguarding the Entire Rescue and Reset ProcessAfter passengers evacuate, the device automatically closes the car and landing doors after a set time to prevent the shaft from being exposed and causing a fall risk. It then enters standby mode, continuously monitoring the mains power restoration status. Once mains power is restored, the system automatically switches back to normal power supply mode and uploads the rescue record to the monitoring center for subsequent maintenance analysis.In conclusion, although the elevator automatic rescue operating device operates in a "black box" during a power outage, it constructs a highly reliable self-rescue system through intelligent energy management, multi-source positioning, flexible control, and multiple door opening mechanisms. It is not only a technological marvel but also a silent practice of the "life first" principle—ensuring that every unexpected elevator stop is no longer a helpless wait but an automated journey to safety.
