It's designed exclusively for the 3VA1 and 3VA20 through 3VA25 molded-case breaker frames. When the control voltage falls, the release opens the breaker mechanism — standard practice for motor feeders, conveyor lines, or crusher drives where an undervoltage condition should isolate the load rather than let it re-accelerate unpredictably. It's a compact unit: 28.8 mm deep, 25.7 mm wide, 65.1 mm tall, with three slots for wiring and a 10 mm strip length on the terminals.
Ratings that matter for the panel
Surge voltage resistance is 4 kV, which aligns with overvoltage category III in a 230/400 V distribution panel. That means it withstands switching transients and indirect lightning-induced spikes without failing — a real concern in mining or mill environments where long cable runs and frequent motor switching are the norm. The stripped length spec of 10 mm (0.4 in) is standard for spring-cage or screw terminals on this class of accessory. Use ferrule-ended stranded wire at that strip length to avoid stray strands shorting to adjacent slots.