1. Basic Working Principle
The Otis OVF20 drive adopts mature AC-DC-AC variable frequency speed regulation technology to ensure stable and efficient elevator operation. The external AC power supply (380V or 220V) is first converted into steady DC voltage through the built-in rectifier module. The DC link capacitor further filters and stabilizes the rectified voltage to eliminate voltage fluctuations.
Subsequently, the internal inverter unit applies Pulse Width Modulation (PWM) technology to convert the smoothed DC power into adjustable AC power with variable frequency and voltage. This precise power conversion process realizes stepless speed regulation of the elevator traction motor, laying a foundation for smooth elevator starting, running and stopping.
2. Core Components of OVF20 Drive
The OVF20 drive features a modular and compact structural design, with the MCBII board serving as the core control unit. Short for Motion Control Board 2, the MCBII is the central signal processing and control hub of the entire drive system. All input and output signal interfaces of the drive are integrated on this board, undertaking all signal reception, analysis and instruction output work.
During operation, elevator speed commands transmitted from the main control cabinet (released by LBII, LCBII and other main control boards) and various hoistway safety signals are synchronously transmitted to the MCBII board. After intelligent analysis and processing, the MCBII outputs precise control instructions to the PDB (Power Driver Board).
As the dedicated power drive unit of the inverter, the PDB board controls the on-off state of the high-power transistor group, thereby completing the final AC power inversion and driving the traction motor. It is worth noting that the PDB board works strictly in accordance with the control logic of the MCBII board to ensure coordinated and accurate system operation.
In addition, the MCBII board receives real-time speed feedback signals from the PVT speed sensor. By comparing the actual operating speed with the system’s preset speed parameters, it dynamically adjusts the output power and frequency, realizing closed-loop precise speed control and ensuring stable and consistent elevator operation.
3. Protection and Braking System
To guarantee safe and reliable long-term operation, the Otis OVF20 drive is equipped with a complete built-in protection system. High-precision current sensors are installed on the inverter’s motor output loop, which monitor the real-time output current of the drive throughout the operation process.
Once the output current exceeds the rated safe range due to overload, short circuit or other abnormal conditions, the system will immediately trigger the over-current protection mechanism, automatically cut off the output and shut down the operation effectively. This prevents damage to the drive, motor and other core equipment, and avoids potential safety hazards.
Meanwhile, the Otis OVF20 drive is equipped with a matching braking resistor. It provides reliable dynamic braking force during elevator deceleration, stopping and emergency braking, which effectively absorbs regenerative electric energy, stabilizes the braking process, avoids jitter and impact, and further improves the safety and comfort of elevator operation.
Post time: Aug-20-2026