Description
ABB NFZ44E-23(1SBH136001R2344)
- Technical Specifications:
- Poles: 4 (4 × NO — normally open main contacts)
- Rated Operational Current (Ie):
- AC-3 (400 V): 25 A → motor power ≈11 kW @ 400 V (2-pole used for 1-ph; 3-pole for 3-ph — 4th pole often for auxiliary or N-switching)
- AC-1 (resistive, ≤60 °C): 40 A @ ≤440 V
- Rated Insulation Voltage (Ui): 690 V
- Rated Impulse Withstand (Uimp): 6 kV
- Coil Voltage: 230 V AC 50/60 Hz (electronically controlled coil — low hum, reduced pick-hold power)
- Pick-Up / Drop-Out Time: ≤20 ms / ≤15 ms (typical)
- Mechanical Life: >10 million operations
- Electrical Life: ≈1.2 × 10⁶ ops @ AC-3 rated; ≈0.2 × 10⁶ @ AC-1 full load
- Auxiliary Contacts: Typically 1 NO + 1 NC on top (CA4-10/CA4-01) — sold separately unless “with aux” noted
- Mounting: 35 mm DIN rail (EN 60715)
- Terminals: Screw (M4) — accepts 1.5–10 mm² stranded; box lug for power; control terminals accept 0.5–2.5 mm²
- Dimensions (approx.): 45 mm (W) × 86 mm (H) × 105 mm (D)
- Certifications: IEC 60947-4-1, UL 508, CSA, CE, CCC
- Functional Features:
- Built-in surge suppressor (varistor / RC across coil — AC-coil AF has electronic coil with integrated suppression)
- Silent coil operation — no 100 Hz hum (electronic coil)
- Wide ambient tolerance (−25 °C to +55 °C full rating; −40 °C to +70 °C with derating)
- Snap-on front-mount auxiliary contact blocks, mechanical interlock kits (for star-delta / reversing pairs), timer blocks
- Application Scenarios:
- 3-phase motor switching (25 A AC-3 → 11 kW @ 400 V) — 3 poles used; 4th pole can switch neutral or used as auxiliary contact via jumpering
- Resistive heating load switching (AC-1 — up to 40 A @ ≤440 V)
- Power contactor for capacitor bank switching (de-rate per PF — consult ABB capacitor switching guide)
- Interposing contactor controlled by PLC DO module (24 V DC via interposing relay or directly if coil voltage matches)
- Material & Structure:
- Housing: Gray polyamide (PA66), UL 94 V-0, with transparent contact status inspection window
- Main Contacts: Silver alloy (AgCdO or AgSnO₂) — arc-chute designed for AC-3 breaking
- Coil: Electronic (AC coil version — rectified & regulated internally)
- DIN-clip: Integral with rear bracket; can be panel-mounted with screws (2 × M4)
- Working Principle:
When coil is energized (230 V AC applied across A1/A2), the electronic driver closes a power MOSFET/thyristor which feeds the contactor’s electromagnetic coil with regulated DC — generating magnetic flux that attracts the moving armature, closing the 4 main NO contacts and the auxiliary contacts (if fitted). On coil de-energization the armature releases under spring force, opening contacts. Arc quenching occurs in the molded arc chutes above each pole.
- Installation Requirements:
- Mount on 35 mm DIN rail; leave ≥10 mm above/below for ventilation
- Tighten power terminals to specified torque (typically 2.5–3.5 N·m for M4 screws); use properly sized ferrules
- Wire coil A1/A2 to control circuit (230 V AC); verify control voltage present before test
- Fit auxiliary contact block (CA4-..) if required — snaps onto front of contactor
- For reversing / star-delta: install mechanical interlock (MK-x) between two contactors to prevent simultaneous closure
- Precautions:
- Verify coil voltage — applying 400 V AC to 230 V coil destroys it instantly; applying 24 V DC to AC coil results in no pick-up
- For capacitive or highly inductive DC loads — contact rating differs; use DC-rated contactor
- For frequent switching (>30 ops/hr at full load) consider contactor AC-4 rating (typically 40–60 % of AC-3) — upsize if needed
- Ensure correct tightening torque — loose connection causes overheating & contact failure
- When switching motors with electronic VFD: contactor is usually upstream as isolator/disconnect; do NOT switch VFD output — switch line side only
