What this voltage relay does that a standard phase monitor cannot
The K8AB-VS1 100/115VAC is a dedicated voltage sensing relay from Omron's K8AB-VS series, designed to monitor AC or DC voltage levels down to the millivolt range — 6 to 300 mV AC/DC trip threshold. That sub-volt sensitivity is what sets it apart from a standard phase-loss or overvoltage relay that typically starts at 1 V or higher. It operates on a 100 to 115 VAC control supply and switches a single SPDT (1 Form C) relay output rated 6 A at 250 VAC. The adjustable delay from 0.1 to 30 seconds lets you time-grade the response so momentary dips don't trigger nuisance trips on the line.
Sourcing reality — obsolete, not gone
Omron lists the K8AB-VS1 100/115VAC as obsolete. The part is still available through independent surplus and broker channels — quantities are lot-specific and confirmed at RFQ, not held in stock. For a line-down situation or a BOM that needs this exact order code, the sourcing path is a quoted-to-order RFQ through distribution that can locate the remaining inventory. No pin-compatible alternative from the K8AB-VS family has been designated as a formal successor.
DIN rail integration and panel fit
The relay mounts on standard DIN rail, so it slots into an existing control panel alongside other K8AB-series monitors or general-purpose relays. The box-style package occupies a single module width — no special cutout or panel drilling needed. Rated for -20°C to 60°C operating ambient, it handles the thermal environment inside a closed electrical enclosure without forced cooling, provided the panel design keeps internal rise within that window.