Aichi Electric 21V2-2FD-E Automatic Transfer Switch

The Aichi Electric 21V2-2FD-E Automatic Transfer Switch is a UL-recognized two-pole transfer switch in the W2 series that automatically routes a load between two power sources (Source I and Source II). It is a 100A device configured for a double-throw transfer (I ⇄ II) with flexible terminal options that support front- or rear-mounted connections, and it includes provisions for manual operation during maintenance when the circuit is de-energized. Automatic switching requires an external control circuit that integrates a power-outage detection relay and related control logic, a common setup for reliable standby-power systems. This design targets critical-load applications—such as servers, industrial controls, and process equipment—where uninterrupted power is essential, and it can be augmented with standard W2 accessories like main-terminal covers and auxiliary switches to tailor installation to exact requirements.