Technical Specifications

Main Features and Advantages

Wide-input swallows site-voltage variance: The ABB 1SFB527068D7084​ takes anything from 100 V AC (Japanese/US light-industrial) to 250 V AC (European site) and the same span on DC (110 V DC / 220 V DC station battery). That means one spare SKU covers both sides of a multinational fleet — a US plant running 120 V AC/DC MCC and a EU plant running 230 V AC can both stock the 1SFB527068D7084​ without splitting BOMs. For plants that run both 110 V DC and 220 V DC station batteries across different yards (common in refineries and power-plant aux), the same board works on both — no jumper, no selector switch, the front-end auto-ranges.≥90% efficiency in a hot MCC bucket: An AF1350 contactor coil can draw 8–10 A on the 24 V side during pick/hold; a linear dropper would dissipate 80+ W as heat into a crowded MCC vertical. The ABB 1SFB527068D7084​ as a switching supply keeps that to ~24 W at full load, which helps the MCC-room summer ambient stay manageable and reduces the thermal cycling that kills neighboring relays. For MCC lines with three AF1250/AF1350 starters stacked vertically, the cumulative heat difference between a switcher and a linear dropper can be 150 W per bucket — measurable on the HVAC load of the motor room.Quad hardware protection baked in: The 1SFB527068D7084​ doesn’t rely on an upstream MCB alone — the board itself OCP-latches on a coil short, OVP-clamps on a line surge (lightning on the 230 V feed, VCB switching transient coupled through), SCP crowbars on a terminal screwdriver slip, and OTP derates/shuts if the MCC bucket ambient climbs past design. That containment means a failed contactor coil (common failure mode: winding short, coil draws 15 A on the 24 V side) blows the board’s OCP latch but doesn’t trip the MCC vertical’s main CB or propagate onto the DCS 24 V auxiliary rail that may share the same site PSU. The ABB 1SFB527068D7084​ isolates the fault to the one starter bucket.DIN footprint continuity: At 170 × 105 × 32 mm and ~120 g, the ABB 1SFB527068D7084​ clips onto a 35 mm DIN top-hat beside the AF1350 contactor body, the overload relay, and the terminal block row — the standard AF starter-bucket layout. Removable terminal blocks mean a swap doesn’t require re-terminating 6+ wires (L/N in, 24 V+/0 V out, aux sense). For panel builders this keeps the starter-bucket BOM clean: AF1350 + 1SFB527068D7084​ + overload + terminals = one vertical. For MRO, it means the “contactor chatters / won’t pick / coil driver overheats” ticket is a 10-minute DIN-swap instead of a rewire.AF1250/AF1350 specificity: This board is not universal across the whole AF range — the small/medium AF (AF09–AF370) have built-in wide-range coil electronics and don’t need an external 1SFB527068D7084. It’s the 1250 A / 1350 A frames where ABB externalized the coil-driver PSU, likely for thermal reasons (the coil current + driver dissipation on a 1350 A contactor is too much to bury inside the contactor housing). So if you’re buying the ABB 1SFB527068D7084, confirm you’re on AF1250 or AF1350 — putting it on a smaller AF is harmless (it’ll power it) but wasteful; putting a small-AF built-in-coil onto a 1350 without the 1SFB527068D7084​ won’t work because the 1350 expects the external DC.

Application Field

The ABB 1SFB527068D7084​ deploys almost exclusively in MCC buckets and switchgear panels that carry AF1250​ or AF1350​ large contactors. The canonical installs:

• Motor Control Centers (MCCs)​ — large induction-motor starters for crushers, mills, compressors, pumps, and fans where the FLA lands in the 600–1200 A range and the starter uses an AF1250 or AF1350. The ABB 1SFB527068D7084​ lives on the DIN beside the contactor, fed from the bucket’s 230 V AC control-transformer secondary or the plant’s 110/220 V DC station battery, and sends clean 24 V DC to the AF coil plus the bucket’s 24 V aux (PLC input from auxiliary contact, beacon, test switch).
• Capacitor-bank switching​ — AF1350 is a common spec for HV/MV capacitor-step switching (the contactor handles the step-current inrush). The 1SFB527068D7084​ gives the coil a clean 24 V even when the capacitor-bank control panel’s 230 V AC sags under inrush of a parallel step.
• Transformer / gen-set bypass line-ups​ — AF1250/AF1350 as the main-coupler contactor in LV switchgear (≤690 V). The ABB 1SFB527068D7084​ here is often fed from the gear’s 230 V AC control mains and also backs up the “breaker-open / contactor-open” beacon chain.
• UPS / static-bypass panels​ — where the bypass contactor is AF1350 class and the UPS’s 230 V control section feeds the 1SFB527068D7084​ to drive the coil independently of the UPS inverter’s 24 V rail.

Failure modes that drive ABB 1SFB527068D7084​ replacement: AF contactor “chatters” on pick (coil voltage sagging under load — board’s output caps drifting), contactor won’t pick at all (board dead, input fuse blown, or OVP latch from a surge), or the MCC bucket’s 24 V aux (DCS status, beacon) goes dark while the 230 V feed measures fine (board’s 24 V reg section failed). Because the 1SFB527068D7084​ sits in a warm MCC bucket and the electrolytics age on a ~12–15 year curve, proactive spare stock — one ABB 1SFB527068D7084​ per AF1250/AF1350 bucket type, plus 1–2 float per MCC line-up — is standard MRO. The board is also a retrofit buy: plants that originally installed AF1250/AF1350 with a different coil-driver PSU (older ABB code or third-party) and want ABB-native form-fit move to the 1SFB527068D7084​ for the warranty/lifecycle match.One boundary worth stating: the 1SFB527068D7084​ is only the coil-driver / 24 V aux PSU. It does not carry overload protection (that’s the separate thermal/motor-protect relay on the AF1350), does not carry the control-logic (that’s the PLC/DCS), and does not carry the contactor main-pole switching (that’s the AF1250/AF1350 mechanically). The board is the “give the coil clean 24 V” layer — nothing more, nothing less. Mixing this up with “AF contactor coil” or “AF overload relay” is the common misorder.

Related Products

• ABB AF1250 / AF1350​ – 3-pole large contactors (1250 A / 1350 A) that the 1SFB527068D7084​ is specified to drive; the board is essentially the external coil-driver for these frames.
• ABB AF Series (AF09–AF370)​ – Smaller AF contactors with built-in wide-range coil electronics; these do not require the 1SFB527068D7084​ — useful contrast when auditing a mixed-AF MCC.
• ABB 1SFB527068D7083 / D7085​ – Sibling revisions of the same 1SFB527068 base (if they exist in dealer listings); verify the D7084 suffix before substituting — D7083/D7085 may differ on input span or FW monitor port.
• ABB EF / TF / MF overload relays​ – Thermal/motor-protect relays that mount beside the AF1350 on the same DIN; often serviced in the same MCC ticket as the ABB 1SFB527068D7084.
• ABB S200 / S800 MCBs​ – The control-circuit protection upstream of the 1SFB527068D7084​ (230 V AC control transformer → S200 MCB → board input); commonly replaced in the same PM window.
• ABB 1SAY130130R0100 / 1MRK000173-CCR00 / 1MRK002239-BB / 1KHL015107R0001​ – Other ABB spares from this series (connection cable, protection binary I/O, Relion PSU, Symphony Plus DCS); all can co-exist in a multi-vintage ABB plant where the 1SFB527068D7084​ handles LV contactor coil duty while those others handle DCS, protection, and drives.

Installation and Maintenance

Pre-installation preparation: The ABB 1SFB527068D7084​ mounts on 35 mm DIN inside an MCC bucket or LV switchgear panel, so prep starts at the bucket’s 230 V AC control-transformer secondary (or 110/220 V DC station battery) and the 24 V DC load side (AF contactor coil + aux). LOTO the MCC bucket’s control-fuse / disconnect, verify 0 V at the board’s input terminals and also at the 24 V output (the AF coil can hold charge on the 24 V side for a few seconds after disconnect). Photograph the terminal-block wiring before extraction — the ABB 1SFB527068D7084​ uses removable terminals on most builds, so you can unplug the block, swap the board, and re-plug, but label every wire: L/N (or 110/220 V DC +/-), 24 V+, 0 V, aux-sense return. If the old board failed as “contactor chatters / won’t pick,” meter the AF1350 coil resistance before powering up the replacement 1SFB527068D7084​ — a shorted coil (winding fault) will immediately OCP-latch a fresh board and fool you into thinking the new board is bad. Also check the upstream S200 MCB rating: the ABB 1SFB527068D7084​ at 10 A output plus losses pulls ~2.5–3 A on the 230 V input side; a 2 A MCB will nuisance-trip on pick inrush.Maintenance recommendations: The ABB 1SFB527068D7084​ is largely solid-state, but MCC annual PM should include a visual on the electrolytics (bulge/vent = end-of-life, common at 10–12 years in hot MCC rooms), a check on the DIN clip latch (vibration from contactor close — AF1350 pick is a heavy thunk — can work the clip loose over years), and a voltage-check on the 24 V output under load (should hold 24 V ±1% with the AF coil picked; sag to 22–23 V means output caps drifting, pre-failure sign). If the bucket has an RS-485 monitor port wired (FW-dependent), the DCS/SCADA can trend the board’s health — use it. For MRO stores, key the ABB 1SFB527068D7084​ to “AF1250 bucket / AF1350 bucket” rather than just “1SFB527068” — the D7084 suffix is the one that matches the AF1250/AF1350 coil-driver spec; other D708x suffixes in the same 1SFB527068 base may be for different contactor frames or different input spans. Keep ESD discipline handling — the board’s secondary side talks to the AF coil driver ICs, not hyper-sensitive logic, but a zap on the 24 V reg section can still kill a channel.