Changeover-type Automatic Transfer Switch (ATS) panels rated from 250A to 2500A, 4-pole at 415V AC, 50Hz. Uses a motorized changeover switch mechanism for reliable make-before-break or break-before-make transfer between mains and generator. The changeover switch provides a visible and lockable isolation point with a clear ON–OFF–ON position indication. Each panel includes a digital ATS controller with adjustable voltage and frequency thresholds, transfer and retransfer time delays, generator start/stop signal outputs, and mode selection (Auto–Manual–Off). Standard protection includes over-voltage, under-voltage, phase rotation, phase voltage unbalance, and frequency monitoring on both sources. Supplied in IP55 powder-coated steel enclosures with indication lamps, alarm outputs, and terminal connections for generator interface. Optional Modbus RTU communication, battery charger, analog metering, and space heater available. Ideal for commercial buildings, hotels, hospitals, and mid-size industrial facilities.