Description
Overview
The Eaton Bussmann 450FMM is a high speed, double barrel, BS88 Type Class aR semiconductor protection fuse engineered for the fast-acting protection of power semiconductors in industrial drive and converter applications. Rated at 450 A and 690 V AC (450 V DC) with a 200 kA breaking capacity, this fuse from the Bussmann FMM series provides the sub-cycle interruption speed necessary to protect sensitive thyristors, diodes, and IGBTs before damage can occur. It meets BS88 Part 4 and IEC 60269-4 standards and is both CE marked and RoHS compliant.
Key Features
- High Speed Semiconductor Protection — Class aR rating ensures sub-cycle response times critical for protecting thyristors, diodes, SCRs, and IGBTs from destructive fault currents.
- Double Barrel Construction — Dual barrel body design offers high breaking capacity and consistent arc interruption performance in a compact form factor.
- 200 kA Breaking Capacity — Handles very high prospective fault currents typical in industrial power systems, providing robust protection in high-fault-energy environments.
- Wide Voltage Coverage — Rated 690 V AC and 450 V DC, covering a broad range of industrial drive and converter circuit topologies including DC bus and AC input configurations.
- 450 A Current Rating — Suitable for high-power drive systems, large rectifier banks, and industrial converter cabinets requiring heavy-duty semiconductor fusing.
- IEC 60269-4 and BS88 Part 4 Compliance — Meets internationally recognized standards ensuring interoperability and regulatory acceptance across global and Indian industrial projects.
- CE Marked and RoHS Compliant — Meets European conformity requirements and restricts hazardous substances, supporting compliance with export and environmentally conscious procurement policies.
- IEC Rated and UL Recognized — Dual certification provides flexibility for installations requiring either IEC or UL documentation for panel approval and factory acceptance testing.
Technical Specifications
| Specification | Value |
|---|---|
| Catalog Number | 450FMM |
| Series | Bussmann FMM |
| Fuse Type | High Speed British Standard Double Barrel |
| Fuse Class | Class aR |
| Amperage Rating | 450 A |
| Voltage Rating (AC) | 690 V |
| Voltage Rating (DC) | 450 V |
| Breaking Capacity | 200 kA |
| Standard | BS88 Part 4, IEC 60269-4 |
| Compliances | CE Marked, RoHS Compliant |
| Certifications | IEC Rated, UL Recognized |
| Application | Semiconductor protection, DC drives, VFDs, power converters, rectifiers, soft starters, thyristor stacks, DC common bus |
Applications & Selection Guide
The 450FMM is the correct choice when you need to protect power semiconductors — such as thyristors, SCRs, diodes, and IGBTs — from fault currents in high-power industrial applications. It is widely used in DC drive input and output circuits, variable frequency drive (VFD) front-end rectifiers, soft starter bypass configurations, thyristor stacks for heating and motor control, power converters, and DC common bus architectures where conventional gG or gL fuses are too slow to prevent semiconductor damage.
As a Class aR fuse, the 450FMM is optimized for back-up semiconductor protection and should be used in conjunction with appropriate semiconductor-rated contactors and circuit breakers. The 690 V AC rating makes it suitable for standard 3-phase industrial power systems in India, while the 450 V DC rating covers applications in DC bus topologies, battery-backed drives, and regenerative converter systems. Always verify the I²t let-through value of the fuse against the I²t withstand capability of the semiconductor device being protected.
In India, this fuse series is widely used in industries including steel and metals processing, textile machinery, paper and pulp, cement plants, sugar mills, automotive manufacturing, and renewable energy inverter systems — all of which rely on high-power drives and converters in Coimbatore and across Tamil Nadu, Maharashtra, Gujarat, and other industrial states. Shansen Enterprises stocks and supplies Bussmann FMM series fuses for panel builders, OEMs, and plant maintenance teams throughout India.
Why Buy from Shansen Enterprises?
- Authorized Eaton Channel Partner in Coimbatore — guaranteed genuine products with full manufacturer backing
- 100% genuine Eaton Bussmann fuses supplied with warranty and authentic documentation
- Pan-India delivery to all major industrial hubs including Chennai, Bangalore, Mumbai, Pune, Hyderabad, and beyond
- WhatsApp technical support for fuse selection, I²t coordination, and application queries
- Competitive bulk pricing for panel builders, OEMs, EPC contractors, and plant procurement teams
Compatible Products & Accessories
- Eaton Bussmann FMM Series fuses — other current ratings (e.g., 100FMM, 200FMM, 315FMM, 500FMM) for system coordination
- Eaton Bussmann BS88 semiconductor fuse holders and DIN-rail fuse bases compatible with double barrel FMM fuses
- Eaton Bussmann fuse status indicators and blown fuse microswitch accessories for remote monitoring
- Eaton semiconductor-rated contactors and motor protection relays for complete drive protection assemblies
- Eaton Bussmann gR and aR fuses for coordinated upstream and downstream protection in converter panels
Frequently Asked Questions
What does Class aR mean and why is it required for semiconductor protection?
Class aR (current-limiting, range-rated) fuses are specifically designed for semiconductor protection. Unlike general purpose gG fuses, Class aR fuses operate at extremely high speed — typically within a half cycle — to interrupt fault currents before they can destroy sensitive thyristors, diodes, SCRs, or IGBTs. The 450FMM is a Class aR fuse and must be used in semiconductor protection applications rather than standard gG or gL fuses, which are far too slow to prevent semiconductor damage under fault conditions.
Can the 450FMM be used on both AC and DC circuits?
Yes. The Eaton Bussmann 450FMM is rated for 690 V AC and 450 V DC, making it suitable for use on both AC input protection circuits (such as VFD or converter input stages) and DC bus protection circuits. Always confirm that the application voltage does not exceed the respective AC or DC voltage rating. For DC applications, the circuit DC voltage must not exceed 450 V.
What is the breaking capacity of the 450FMM and why does it matter?
The 450FMM has a breaking capacity of 200 kA. Breaking capacity (also called interrupt rating) is the maximum prospective fault current the fuse can safely interrupt without rupturing or causing a hazardous failure. A 200 kA rating makes the 450FMM suitable for installations close to high-capacity transformer secondaries and large industrial busbars where prospective fault currents can be very high. Always verify that the installation’s available fault current does not exceed 200 kA.
What is the difference between FMM series double barrel fuses and standard cylindrical or square body semiconductor fuses?
The Bussmann FMM series uses a double barrel body construction conforming to BS88 Part 4, which provides a specific fuse holder bolt pattern and terminal configuration different from square body (North American style) or standard cylindrical semiconductor fuses. The double barrel format is common in European-style and BS88-based panel designs widely used in India. It is important to select fuse holders and fuse bases that are specifically rated and dimensioned for the FMM double barrel series to ensure correct mechanical and electrical contact.
Is the 450FMM compliant with Indian industrial standards and CE requirements?
The Eaton Bussmann 450FMM is compliant with IEC 60269-4 and BS88 Part 4, which are the internationally accepted standards referenced by Indian industrial and electrical installation regulations. It is CE marked for European conformity, RoHS compliant for restriction of hazardous substances, IEC rated, and UL recognized — making it acceptable for panel builders and OEMs in India who export to or follow IEC or UL documentation requirements for factory acceptance testing and customer approvals.
How do I order the Eaton Bussmann 450FMM from Shansen Enterprises?
You can order the Eaton Bussmann 450FMM directly from Shansen Enterprises, authorized Eaton channel partner in Coimbatore, Tamil Nadu. Contact us via WhatsApp or email using the quote buttons on this page, quoting catalog number 450FMM along with the required quantity. Our team will respond with pricing, availability, and delivery timeline for your location across India. Bulk orders for panel builders and OEMs are welcome and receive preferential pricing.
