What the 16 A AC-3 rating means for motor starting
The 3RA2120-4AD26-0BB4: The 16 A at 400 V AC-3 rating covers standard squirrel-cage motor starting — breaking the stalled rotor current, not just the running load. Class 10 trip means the overload relay will open within 10 seconds at 7.2x the current setting — tight enough to protect the motor winding during a stall without nuisance tripping on a normal start. Maximum AC-3 voltage is 690 V, so this starter can also serve 480 V or 600 V motor circuits at the same 16 A rating.
Busbar snap-on and panel layout constraints
This S0-size starter snaps directly onto 60 mm busbar systems — no DIN rail adapter needed. That saves a mounting step and keeps the assembly height predictable. The footprint is 45 mm wide by 260 mm tall by 165 mm deep. Clearance requirements: 50 mm above, 20 mm in front, 20 mm at the sides, and 10 mm below — zero behind. Plan the enclosure depth around the 165 mm plus the 20 mm forward clearance. Mounting position is vertical only. The supplied contactor is a 3RT2026-1BB40 and the link module is 3RA2921-1BA00 — both factory-integrated, so no loose parts to order separately.
RoHS compliance date is 10/01/2009 — the starter meets the European substance restrictions for current production.