LPJ-400SP is a Class J time-delay current-limiting fuse from the Low-Peak series by Eaton Bussmann, specifically designed for high-inrush loads such as motors and transformers.
- Model Definition
LPJ: Low-Peak™ series, Class J, time-delay
400: Rated current 400A
SP: Special Purpose (industrial/motor protection)
SPI: With blown fuse indicator (optional model: LPJ-400SPI)
- Specifiche tecniche principali
| Parametro | Specifica |
| Corrente nominale | 400UN |
| Tensione nominale | 600V e / 300A DC |
| Interrupting Rating | 300kA@600VAC; 100kA@300VDC |
| Element Construction | Dual‑element time‑delay |
| Time‑Delay Characteristic | ≥10s at 500% In (resists motor starting inrush) |
| Dimensioni | Φ53.59mm × 181mm long (2‑1/8″ × 7‑1/8″) |
| Montaggio | Bolted blade terminals |
| Indicatore | LPJ‑400SP: No indicator; LPJ‑400SPI: With indicator |
| Approvals | UL, CSA, CE, RoHS |
| Compatible Fuse Blocks | JM600 series |
- Applicazioni tipiche
Motor circuits (Centro clienti), variable frequency drives, trasformatori
Distribuzione dell'energia industriale, UPS, PV DC circuits
Applications requiring high current limiting, inrush resistance, and nuisance-trip prevention
- Full Series Models (70–600A)
LPJ-70SP / 80SP / 90SP / 100SP
LPJ-110SP / 125SP / 150SP / 175SP
LPJ-200SP / 225SP / 250SP / 300SP
LPJ-350SP / 400SP / 450SP / 500SP / 600SP
- Cross-Brand Direct Replacements (400A Class J Time-Delay)
| Marca | Modello sostitutivo | Caratteristiche |
| Busmann | LPJ‑400SP | Original, no indicator |
| LPJ‑400SPI | With blown fuse indicator | |
| Littelfuse | JTD‑400 | Identical dimensions and characteristics |
| Mersen (Ferraz) | AJT‑400 | Class J time‑delay, sostituzione diretta |
| Siemens | 3NA6 244‑6 | 400A 600V Class J |
- Selezione & Note di sostituzione
- Class J only: Not interchangeable with Class RK5/H/K; must use Class J fuse holders.
- Time-delay required: Motor circuits must use LPJ/JTD/AJT time-delay fuses; fast-acting types (JKS) are not suitable.
- Indicator upgrade: Use LPJ-400SPI for status monitoring.
- DC applications: Rated at 300V DC, suitable for PV and energy storage DC branches.
Application Scenarios of Eaton Bussmann Fuses
With a full, comprehensive, high-performance product portfolio, Eaton Bussmann fuses cover nearly all electrical protection scenarios from low voltage to high voltage, AC to DC, and industry to new energy, providing reliable overcurrent and short-circuit protection for high-value equipment, critical circuits, and hazardous environments.
- Automazione industriale & Traditional Manufacturing (Core Scenario)
Designed for industrial equipment including motors, VFDs, and PLCs, with emphasis on inrush resistance, time-delay, and current limiting to prevent nuisance tripping.
Motor Control Centers (Centro clienti) / Motor Circuits
Serie: LPJ (Class J), LPN-RK (Class RK5), KTK (Class RK1)
Applicazione: Protect three-phase induction motors, gear reducers, tifosi, pompe. Time-delay characteristics (≥10s at 500% In for LPJ series) withstand motor starting inrush and prevent tripping during frequent starts/stops.
Variable Frequency Drives & Power Electronics
Serie: Fast-acting fuses (FWH, FWX), DIN 43653 square body fuses
Applicazione: Protect VFDs, servo drives, UPS, rectifiers, soft starters. Fast-acting (aR) fuses clear short circuits in microseconds to safeguard expensive semiconductors such as IGBTs.
Distribuzione dell'energia industriale & Transformers
Serie: NH series, KF series, CM series
Applicazione: Low-voltage switchgear, primary/secondary transformer sides, banchi di condensatori. Provides overload and short-circuit protection for main and branch circuits with interrupting ratings up to 300kA.
Control Circuits & Precision Circuits
Serie: FNQ, FNM (Class CC), MDA, MFD
Applicazione: PLCs, relè, instruments, sensors, control power supplies. Compact size for precise protection of low-current control circuits.
- New Energy & Green Power (Fastest-Growing Segment)
Engineered for high-voltage DC, alta affidabilità, and explosion protection, covering the entire PV, wind, energy storage, and electric vehicle industrial chain.
Photovoltaic (PV) Systems
Serie: PV series, 10×38 PV fuses, GDC series
Applicazione: PV combiner boxes, string circuits, inverter DC sides, central inverters. Compatible with 1000V/1500V DC systems, resistant to temperature cycles and DC arcing.
Sistemi di accumulo dell'energia (ESS) & Power Batteries
Serie: EV series, MEV series, 1500V ultra-fast DC fuses
Applicazione: PCS, battery clusters, BMS circuits, containerized ESS. Provides high-voltage DC protection (up to 1500V DC) against thermal runaway and fire risks.
Wind Power Generation
Serie: Medium-high voltage fuses, special time-delay fuses
Applicazione: Wind turbine pitch and yaw systems, nacelle cabinets, pad-mount transformers. Adapted to high altitude, strong vibration, and wide temperature ranges.
Electric Vehicles (EV) & Charging Infrastructure
Serie: EV, MEGA, AM, FWH
Applicazione:
Vehicles: Main battery pack circuits, on-board chargers (OBC), PDUs, motor controllers.
Charging: DC fast chargers, battery swap stations. Rated up to 1000V DC, covering 10A–1600A.
- Centri dati & Telecommunications
Ensures 24/7 uninterrupted power supply with high reliability, bassa perdita di potenza, and modular design.
Applicazioni: UPS input/output, precision air conditioning, server power supplies, telecom base stations, IDC PDUs.
Serie: KTK, FNQ, LPJ, low-voltage blade fuses
Key Benefits: Strong current limiting, fast fault clearing to prevent single-point failures from spreading; low power loss reduces heat and energy consumption.
- Petroleum, Chemical, Coal Mining (Hazardous Environments)
Used in flammable gas and dust atmospheres, requiring explosion-proof and flameproof certifications.
Applicazioni: Explosion-proof motors, flameproof VFDs, oilfield pumping units, chemical reactors, underground coal mine equipment.
Serie: Explosion-proof certified fuses, Ex d flameproof fuse links
Requisiti chiave: ATEX, IECEx, CQST certified to prevent ignition of external explosive gases.
- Transito ferroviario & Marino
Withstands harsh conditions including strong vibration, high humidity, wide temperatures, and dust.
Transito ferroviario
Applicazioni: Traction converters, auxiliary power, signaling systems, door controls for high-speed rail and metro.
Serie: Fast-acting fuses, special time-delay fuses, IN 50155 certified products
Marino & Offshore
Applicazioni: Marine motors, pompe, compressori, navigation equipment.
Certificazioni: ABS, DNV, LR marine type approvals, salt-mist and mold resistant.
- Electric Power Transmission & Distribution (Medium-High Voltage)
Covers full-link protection from power plants to end users.
Applicazioni: Medium-voltage switchgear, transformer protection, banchi di condensatori, cable feeders, transformer protection.
Serie: XRNP (PT protection), XRNM (motor protection), WFN (outdoor)
- Automotive & Construction Machinery
Conventional Vehicles: ATC/ATO blade fuses, MAXI, MEGA, AMI for lighting, aria condizionata, ECUs, starters.
Construction Machinery: Electrical systems for excavators, loaders, gru, resistant to extreme temperatures and vibration.
- Guida alla selezione rapida (By Application)
| Applicazione | Recommended Bussmann Series | Caratteristiche principali |
| Industrial Motors / Transformers | LPJ, LPN‑RK | Time‑delay, inrush resistance, Class J/RK5 |
| VFDs / Semiconductors | FWH, FWX, DIN 43653 | Ultra‑fast, aR, IGBT protection |
| PV / Energy Storage DC | PV, EV, GDC | 1000V/1500V DC, arc resistance |
| Control Circuits / PLC | FNQ, KTK | Compatto, precise, Class CC |
| Hazardous Areas | Ex‑certified series | ATEX/IECEx, flameproof |
| Electric Vehicles | EV, MEGA | High‑voltage DC, automotive‑grade |
- Industrial Motors / Centro clienti / Transformers (For ABB M3JP Explosion-Proof Motors)
Applicazione: Three-phase induction motors, tifosi, pompe, compressori, trasformatori
Typical series: LPJ (Class J), LPN-RK (Class RK5)
| Potenza del motore | Corrente nominale | Recommended Bussmann Model |
| 1.1kW | 2.5UN | LPJ‑2SP |
| 5.5kW | 11UN | LPJ‑10SP / LPJ‑15SP |
| 11kW | 22UN | LPJ‑20SP / LPJ‑25SP |
| 18.5kW | 37UN | LPJ‑35SP / LPJ‑40SP |
| 30kW | 60UN | LPJ‑60SP |
| 45kW | 85UN | LPJ‑90SP |
| 75kW | 140UN | LPJ‑125SP / LPJ‑150SP |
| 160kW | 300UN | LPJ‑300SP |
| 200kW~315kW | 400~600A | LPJ‑400SP, LPJ‑500SP, LPJ‑600SP |
Caratteristiche: Time-delay, resistant to motor starting inrush, no nuisance tripping.
- VFDs, IGBTs, Servos, UPS (Power Electronics Protection)
Applicazione: VFD DC links, rectifiers, inverters, servo drives
Serie: FWH, FWX, 170M (square body fast fuses)
≤22kW VFDs: FWX-10A, FWX-20A, FWH-30A
45~75kW VFDs: FWH-60A, FWH-80A
≥160kW high-power drives: 170M series 200A~600A
Caratteristiche: Ultra-fast aR characteristics, protects expensive semiconductors.
- PV / Energy Storage / High-Voltage DC (1000V / 1500A DC)
Applicazione: PV combiner boxes, strings, PCS, energy storage battery clusters
Serie: PV, EV, GDC, 10×38 PV fuses
PV strings 15A/20A: PV-15A, PV-20A
Combiner boxes 32A: PV-32A
ESS high-voltage DC: EV-315A, EV-400A, EV-500A
Caratteristiche: DC-optimized, arc-resistant, thermal runaway protection.
- Control Circuits / PLC / Relays (For Schneider RXM Relays)
Applicazione: Cabinet control circuits, 24V power supplies, instruments, sensors
Serie: FNQ, FNM, KTK, MDA
1A~10A control circuits: FNQ-1, FNQ-2, FNQ-5, FNQ-10
Compact terminal block protection: KTK-1, KTK-5
- Hazardous Explosion-Proof Environments (Petrochemical, Coal Mining, For M3JP Motors)
Applicazione: Ex d flameproof cabinets, Zone 1/2 hazardous areas
Serie: LPJ-xxSP with explosion-proof certification, Ex-type fuses
Direct usable models:
LPJ-400SP, LPJ-300SP, LPJ-200SP
Suitable for short-circuit protection in hazardous areas when used with flameproof enclosures.
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