What a static transfer switch actually does

A mechanical automatic transfer switch moves a load by throwing a contact. That motion is measured in tens of milliseconds. A static transfer switch moves the load through semiconductors. On the HPS page that device is an SCR path, described as first disconnect then connect, with a typical transfer of ≤6 ms.

Two other published rules matter as much as the time: the cabinet has two independent inlets, and Source A is the priority source. After a transfer to B the switch can return the load to A when A is healthy again.

Open the HPS product page for the current steps and cabinet sizes.