OPERATING METHOD OF AC VARIABLE SPEED SHIFTER

摘要

PURPOSE:To enable to safely and efficiently operate a boiler by inching a motor by utilizing a bypass circuit when an AC variable speed shifter falls in trouble. CONSTITUTION:When a boiler is operated by switching to a direct drive type with a bypass circuit due to a trouble, an airflow controller such as a damper is forcibly closed, an induction motor M is inched by a breaker CB2 until the damper is opened to the opening capable of flowing at the optimum flow rate, and when the damper is opened to the opening capable of flowing at the optimum flow rate for the boiler, the motor M is operated by a continuous commercial power source. Thus, even if the boiler is switched to the commercial power operation by the bypass circuit when a trouble occurs, excess air is not fed to the boiler, but the boiler can be maintained in the optimum air flow range.