The OTIS OVF20 inverter plays a crucial role in modern elevator systems, ensuring smooth and safe operation. Its main function is to convert the AC power supplied to the elevator into a controlled, variable-frequency AC output that drives the motor efficiently.
The process begins with the incoming AC power, either 380V or 220V, which is first converted to DC voltage by the rectifier system inside the inverter. This DC voltage is then stabilized by capacitors in the DC circuit to provide a steady supply. The inverter then uses a pulse-width modulation (PWM) system to transform this rectified DC back into AC voltage with adjustable frequency, completing the inverter process.
Inside the OVF20, the first component visible after opening the front cover is the Motion Control Board II (MCBII). As its name suggests, this board is responsible for controlling the elevator’s motion system. It serves as the interface for all input and output signals of the OVF20 and processes these signals to ensure precise operation.
The elevator control system—such as LBII, LCBII, or other control boards—sends speed commands to the MCBII. The MCBII processes these commands along with additional hoistway signals, including safety circuits. It then sends control signals to the Power Drive Board (PDB), which manages the high-power transistors within the inverter to perform the actual AC conversion. Essentially, the PDB executes the inverter’s power switching under the direction of the MCBII.
For accurate operation, the MCBII also receives feedback from the PVT speed sensor. By comparing the actual speed of the elevator with the commanded speed, the MCBII adjusts the motor output to maintain smooth and reliable movement. Two additional lines from the inverter provide current feedback to the MCBII as part of the inverter’s internal current protection system. If the output current exceeds the rated value, the inverter will trigger a protective shutdown.
Finally, the OVF20 includes a braking resistor system. This resistor is used to safely decelerate the elevator, converting excess energy into heat to ensure controlled and safe stopping.
Overall, the OTIS OVF20 inverter combines precise motion control, real-time feedback, and safety mechanisms to deliver reliable performance for modern elevators.
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Post time: May-21-2026