Description
Overview
The Eaton Bussmann 250FM is a single barrel, high speed BS88-type semiconductor protection fuse from the Bussmann FM series. Rated 250 A at 690 V AC and 450 V DC, it provides ultra-fast fault current interruption up to 200 kA to protect costly power semiconductor devices from thermal and surge damage. Its Class aR rating makes it the correct choice wherever semiconductor-specific protection characteristics — rather than general-purpose gG response — are required in industrial drive and converter panels.
Key Features
- High Speed Response — Class aR characteristic ensures the fuse operates fast enough to protect IGBTs, thyristors, SCRs, and diodes before they reach destructive energy levels.
- 250 A Amperage Rating — Handles substantial continuous load currents typical of medium-to-large drive and converter assemblies.
- 690 V AC / 450 V DC Rated Voltage — Suitable for standard 3-phase 400 V and 690 V industrial power systems as well as DC bus architectures.
- 200 kA Breaking Capacity — Industry-leading interrupting rating provides reliable fault clearing even on stiff, high-fault-level industrial supply networks.
- Single Barrel Construction — Compact, single-element body simplifies mounting and replacement in panel designs.
- BS88 Part 4 / IEC 60269-4 Compliant — Meets the internationally recognised standard for HRC fuses used in semiconductor protection.
- CE Marked and RoHS Compliant — Meets European regulatory requirements for industrial equipment export and domestic use.
- IEC Rated and UL Recognized — Dual certification supports use in both IEC-based Indian and global installations as well as UL-listed equipment.
- Bussmann FM Series Pedigree — Part of Eaton’s proven FM family, widely specified by OEMs and panel builders across India and globally.
Technical Specifications
| Specification | Value |
|---|---|
| Catalog Number | 250FM |
| Brand / Series | Eaton Bussmann / FM Series |
| Fuse Type | High Speed British Standard, Single Barrel |
| Amperage Rating | 250 A |
| Rated Voltage AC | 690 V |
| Rated Voltage DC | 450 V |
| Breaking Capacity | 200 kA |
| Fuse Class | Class aR |
| 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 250FM is the correct fuse selection wherever power semiconductor devices — including IGBTs, SCRs, thyristors, and power diodes — must be protected from short-circuit fault currents. Its Class aR characteristic means it is intentionally designed to operate only on high overcurrents that threaten semiconductor junctions, allowing downstream circuit breakers or other protective devices to handle overload conditions. It is widely specified in VFD panels, DC motor drive cabinets, active front end converters, and multi-drive DC common bus systems where semiconductor replacement costs far exceed fuse cost.
In Indian industrial environments, the 250FM is found in automotive paint shop drives, textile mill variable speed drives, steel rolling mill converters, paper machine drives, and pump/fan VFD panels across Coimbatore, Pune, Ahmedabad, Chennai, and other manufacturing hubs. Its 690 V AC rating provides full compatibility with 11 kV / 690 V transformers used in large process plants, while the 450 V DC rating covers standard DC bus voltages in 415 V drive systems.
When selecting the 250FM, confirm that the fuse I²t let-through value is lower than the semiconductor’s rated withstand I²t. Always consult the drive or converter OEM’s fuse coordination table — Eaton Bussmann provides detailed application guides for FM series fuses. Shansen Enterprises can assist panel builders and OEMs in Coimbatore and across India with fuse sizing and coordination support.
Why Buy from Shansen Enterprises?
- Authorized Eaton Channel Partner in Coimbatore — supplying genuine Eaton Bussmann products with full traceability
- 100% genuine products with manufacturer warranty — no counterfeit risk
- Pan-India delivery — prompt dispatch to Coimbatore, Chennai, Bangalore, Mumbai, Pune, Hyderabad, and beyond
- WhatsApp technical support — quick response for fuse sizing, coordination, and selection queries
- Bulk pricing for panel builders, OEMs, and EPC contractors — competitive rates on volume orders
Compatible Products & Accessories
- Eaton Bussmann FM Series fuse holders and fuse bases for BS88 single barrel fuses
- Eaton Bussmann FWP and FWH series high speed square body fuses (alternative form factor for semiconductor protection)
- Eaton Bussmann striker pin indicator accessories for FM series fuses
- Eaton DIN rail and busbar-mounted fuse carriers for 690 V semiconductor protection panels
- Complementary Class gG BS88 backup fuses for feeder protection upstream of semiconductor equipment
- Eaton variable frequency drives (VFDs) and soft starters requiring Class aR fuse protection
Frequently Asked Questions
What is the difference between a Class aR fuse and a Class gG fuse for semiconductor protection?
A Class gG fuse is a general-purpose fuse designed to protect cables and equipment across the full range from overload to short circuit. A Class aR fuse, such as the Eaton Bussmann 250FM, is a current-limiting high speed fuse that operates only in the high short-circuit current range — it does not provide overload protection on its own. This fast-acting characteristic is essential for protecting semiconductor devices like IGBTs, thyristors, and diodes, which can be destroyed within microseconds by fault currents before a standard gG fuse has time to operate. Always use a Class aR fuse in series with appropriate overload protection when protecting semiconductor assemblies.
Is the Eaton Bussmann 250FM suitable for both AC and DC applications?
Yes. The 250FM is rated 690 V AC and 450 V DC, making it suitable for use in both three-phase AC semiconductor protection circuits and DC bus protection in drive systems. The DC voltage rating of 450 V is appropriate for the DC bus of standard 415 V AC-fed variable speed drives. Always verify that your application voltage does not exceed the fuse’s rated voltage for the supply type (AC or DC) being used.
What breaking capacity does the Eaton Bussmann 250FM provide?
The 250FM has a breaking capacity of 200 kA, which is among the highest available for this class of semiconductor protection fuse. This ensures that the fuse can safely interrupt the maximum prospective fault current likely to be encountered on industrial 690 V distribution systems in India, including those fed from high-capacity transformers with low impedance. Always confirm that the fuse’s breaking capacity meets or exceeds the prospective short-circuit current (PSCC) at the point of installation.
Which industries and applications in India commonly use the Eaton Bussmann 250FM?
The 250FM is widely used across Indian industries wherever power semiconductors require protection. Typical applications include VFD panels in textile mills in Coimbatore and Surat, DC drive panels in steel plants, thyristor-based power controllers in induction heating systems, active front end converters in renewable energy and UPS systems, rectifier assemblies in electroplating and chemical plants, and soft starter panels in pump and HVAC installations. Its 690 V AC rating also makes it suitable for large offshore and marine drive systems.
Does the Eaton Bussmann 250FM comply with CE and RoHS requirements?
Yes. The 250FM carries CE marking, confirming conformity with applicable European directives for low voltage equipment. It is also RoHS compliant, meaning it does not contain restricted hazardous substances such as lead, mercury, or cadmium above permitted thresholds. Additionally, it is IEC rated per IEC 60269-4 and UL Recognized, supporting use in both IEC-based Indian panel builds and equipment destined for UL-listed markets.
How do I order the Eaton Bussmann 250FM from Shansen Enterprises?
Ordering the Eaton Bussmann 250FM from Shansen Enterprises is straightforward. You can contact us via WhatsApp or email using the buttons on this page to request a quotation — simply mention the catalog number 250FM and your required quantity. Our team in Coimbatore will respond promptly with pricing, availability, and delivery timelines for your location anywhere in India. For bulk or recurring OEM orders, ask about our volume pricing and scheduled delivery options.
