1SBN040100R1013 The ABB WA4 mechanical latching unit is used for AF09 to AF96 contactors and NF contactor relays to ensure that the contactor or contactor relay remains switched on even if there is a lack or a failure of voltage. It contains a mechanical latching device with electromagnetic impulse unlatching (AC or DC) or manual unlatching. Screw terminals
Clipped onto the front face of the 1-stack contactor