A regulated DC power supply within the elevator controller that provides stable low-voltage DC power to the control logic, sensors, communication modules, and safety circuits.
Full Definition
The elevator power supply unit (PSU) converts the incoming AC mains supply (or intermediate DC bus voltage from the drive) to stable, regulated DC voltages — typically 24 V DC and 5 V DC — required by the microprocessor control board, input/output modules, sensors, encoder interface, and communication interfaces. A well-regulated PSU is essential for reliable controller operation; voltage fluctuations or ripple can cause random controller faults, safety circuit false trips, and communication errors. Modern PSUs include over-voltage, over-current, and short-circuit protection, and a diagnostic LED or output signal indicating healthy operation. PSU life is typically 10–15 years; replacement is recommended proactively during major modernisation. Battery-backed UPS functionality is sometimes integrated to maintain controller state during brief power interruptions.
