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)
- Key Technical Specifications
| Parametru | Caietul de sarcini |
| Curent nominal | 400O |
| Tensiune nominală | 600V și / 300În DC |
| Interrupting Rating | 300kA@600VAC; 100kA@300VDC |
| Element Construction | Dual‑element time‑delay |
| Time‑Delay Characteristic | ≥10s at 500% În (resists motor starting inrush) |
| Dimensiuni | Φ53.59mm × 181mm long (2‑1/8″ × 7‑1/8″) |
| Montare | Bolted blade terminals |
| Indicator | LPJ‑400SP: No indicator; LPJ‑400SPI: With indicator |
| Aprobari | UL, CSA, CE, RoHS |
| Compatible Fuse Blocks | JM600 series |
- Aplicații tipice
Motor circuits (MCC), variable frequency drives, transformatoare
Distribuția de energie industrială, 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 | Model de înlocuire | Caracteristici |
| Bussmann | 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, înlocuire directă |
| Siemens | 3NA6 244‑6 | 400A 600V Class J |
- Selecţie & Note de înlocuire
- 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.
- Automatizare industrială & 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 (MCC) / Motor Circuits
Serie: LPJ (Class J), LPN-RK (Class RK5), KTK (Class RK1)
Aplicație: Protect three-phase induction motors, gear reducers, fani, 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
Aplicație: Protect VFDs, servo drives, UPS, rectifiers, startere soft. Fast-acting (aR) fuses clear short circuits in microseconds to safeguard expensive semiconductors such as IGBTs.
Distribuția de energie industrială & Transformers
Serie: NH series, KF series, CM series
Aplicație: Low-voltage switchgear, primary/secondary transformer sides, capacitor banks. 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
Aplicație: PLC-uri, relee, instruments, sensors, control power supplies. Compact size for precise protection of low-current control circuits.
- Energie Nouă & Green Power (Fastest-Growing Segment)
Engineered for high-voltage DC, high reliability, 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
Aplicație: PV combiner boxes, string circuits, inverter DC sides, central inverters. Compatible with 1000V/1500V DC systems, resistant to temperature cycles and DC arcing.
Energy Storage Systems (ESS) & Power Batteries
Serie: EV series, MEV series, 1500V ultra-fast DC fuses
Aplicație: 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
Aplicație: 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
Aplicație:
Vehicles: Main battery pack circuits, on-board chargers (OBC), PDU-uri, motor controllers.
Charging: DC fast chargers, battery swap stations. Rated up to 1000V DC, covering 10A–1600A.
- Centre de date & Telecommunications
Ensures 24/7 uninterrupted power supply with high reliability, low power loss, și design modular.
Aplicații: 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.
Aplicații: Explosion-proof motors, flameproof VFDs, oilfield pumping units, chemical reactors, underground coal mine equipment.
Serie: Explosion-proof certified fuses, Ex d flameproof fuse links
Key Requirements: ATEX, IECEx, CQST certified to prevent ignition of external explosive gases.
- Tranzit Feroviar & Marine
Withstands harsh conditions including strong vibration, high humidity, wide temperatures, și praf.
Tranzit Feroviar
Aplicații: Traction converters, auxiliary power, signaling systems, door controls for high-speed rail and metro.
Serie: Fast-acting fuses, special time-delay fuses, ÎN 50155 certified products
Marine & Offshore
Aplicații: Marine motors, pompe, compresoare, navigation equipment.
Certificari: 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.
Aplicații: Medium-voltage switchgear, transformer protection, capacitor banks, 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, aer condiționat, ECUs, starters.
Construction Machinery: Electrical systems for excavators, loaders, macarale, resistant to extreme temperatures and vibration.
- Quick Selection Guide (By Application)
| Aplicație | Recommended Bussmann Series | Key Features |
| Motoare industriale / 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 | Compact, precise, Class CC |
| Hazardous Areas | Ex‑certified series | ATEX/IECEx, flameproof |
| Electric Vehicles | EV, MEGA | High‑voltage DC, automotive‑grade |
- Motoare industriale / MCC / Transformers (For ABB M3JP Explosion-Proof Motors)
Aplicație: Three-phase induction motors, fani, pompe, compresoare, transformatoare
Typical series: LPJ (Class J), LPN-RK (Class RK5)
| Motor Power | Curent nominal | Recommended Bussmann Model |
| 1.1kW | 2.5O | LPJ‑2SP |
| 5.5kW | 11O | LPJ‑10SP / LPJ‑15SP |
| 11kW | 22O | LPJ‑20SP / LPJ‑25SP |
| 18.5kW | 37O | LPJ‑35SP / LPJ‑40SP |
| 30kW | 60O | LPJ‑60SP |
| 45kW | 85O | LPJ‑90SP |
| 75kW | 140O | LPJ‑125SP / LPJ‑150SP |
| 160kW | 300O | LPJ‑300SP |
| 200kW~315kW | 400~600A | LPJ‑400SP, LPJ‑500SP, LPJ‑600SP |
Caracteristici: Time-delay, resistant to motor starting inrush, no nuisance tripping.
- VFDs, IGBTs, Servos, UPS (Power Electronics Protection)
Aplicație: VFD DC links, rectifiers, invertoare, 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
Caracteristici: Ultra-fast aR characteristics, protects expensive semiconductors.
- PV / Stocarea Energiei / High-Voltage DC (1000V / 1500În DC)
Aplicație: 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
Caracteristici: DC-optimized, arc-resistant, thermal runaway protection.
- Control Circuits / PLC / Relays (For Schneider RXM Relays)
Aplicație: 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)
Aplicație: 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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