SINOFUSE RS309-MF Series 700V/750V High-Speed Bolt-Mounted Fuse
The SINOFUSE RS309-MF Series is a cylindrical bolt-connected high-speed fuse family designed for demanding AC and DC protection applications. The series covers rated currents from 5A to 800A and is available in multiple mechanical sizes for electric vehicle, power conversion, energy storage, charging, and industrial power-electronic systems.
According to the SINOFUSE selection specification, RS309-MF fuses are rated at AC/DC 700V under IEC specifications and DC 750V under UL specifications. The series uses the aR utilization category and combines compact construction, low pre-arcing I²t, high breaking capacity, and resistance to current surges, mechanical vibration, impact, wide temperature changes, and chemical loads.
RS309-MF Series Technical Specifications
- Manufacturer: SINOFUSE
- Series: RS309-MF
- Product Type: Cylindrical bolt-connected high-speed fuse
- Rated Voltage: AC/DC 700V (IEC), DC 750V (UL)
- Rated Current Range: 5A to 800A
- Utilization Category: aR
- AC Breaking Capacity: 100kA
- DC Breaking Capacity: 50kA, time constant ≤15ms
- Performance Standards: UL 248 and IEC 60269
- Environmental / Application Reliability Reference: ISO 8820 and GB/T 31465
- Approvals / Compliance: CE, UL and RoHS
Key RS309-MF Features
- Compact cylindrical construction
- Low pre-arcing I²t
- High interrupting capability
- Resistance to current surge conditions
- Designed to withstand strong mechanical vibration and impact
- Suitable for wide temperature variation
- Designed for demanding road-vehicle electrical environments
Typical Applications
The manufacturer specifies the RS309-MF Series for protection in road-vehicle and power-electronic applications, including:
- Electric vehicle drive power systems
- Power conversion systems
- Energy storage and power systems
- Variable frequency controllers
- Charging equipment
- Electrical conductors
- Automotive electrical devices and equipment
- Short-circuit protection
- Overload protection
- Backup protection
RS309-MF Model and Size Range
The RS309-MF family contains 31 current ratings from 5A through 800A. Different current ranges use different mechanical size codes and mounting hardware.
| Size Code | Current Range | Typical Models | Mounting Bolt | Recommended Torque |
|---|---|---|---|---|
| 2YA | 5A–30A | RS309-MF-5A to RS309-MF-30A | M6 | 6 ±1 N·m |
| 3SA | 35A–60A | RS309-MF-35A to RS309-MF-60A | M8 | 12 ±1 N·m |
| 4SB | 70A–100A | RS309-MF-70A to RS309-MF-100A | M8 | 12 ±1 N·m |
| 6TA | 125A–200A | RS309-MF-125A to RS309-MF-200A | M10 | 21 ±1 N·m |
| 7TA | 225A–450A | RS309-MF-225A to RS309-MF-450A | M10 | 21 ±1 N·m |
| 7TD | 500A–600A | RS309-MF-500A to RS309-MF-600A | M12 | 28 ±1 N·m |
| 7TC | 700A–800A | RS309-MF-700A to RS309-MF-800A | M12 | 28 ±1 N·m |
Mechanical Size Reference
The RS309-MF Series uses seven mechanical size codes. The following dimensions are specified in millimeters by the manufacturer.
| Size | A | B | C | D | E | F | G | H |
|---|---|---|---|---|---|---|---|---|
| 2YA | 73.5 | 14.3 | 47.6 | 60.5 | 63.5 | 6.5 | 10.3 | 1.6 |
| 3SA | 110 | 20 | 66 | 84 | 95.5 | 9 | 15 | 3.3 |
| 4SB | 110 | 24 | 66 | 84 | 95.5 | 9 | 18 | 3.2 |
| 6TA | 129 | 37 | 72 | 89 | 109 | 10.5 | 25 | 6 |
| 7TA | 129 | 49 | 72 | 89.5 | 109 | 10.5 | 38 | 6 |
| 7TD | 180 | 49 | 72 | 106 | 145 | 13.5 | 38 | 6 |
| 7TC | 168 | 49 | 72 | 128.5 | 141.5 | 16 | 38 | 6 |
Complete RS309-MF Current Ratings
Available models include:
RS309-MF-5A, 10A, 15A, 20A, 25A, 30A, 35A, 40A, 45A, 50A, 60A, 70A, 80A, 90A, 100A, 125A, 150A, 175A, 200A, 225A, 250A, 275A, 300A, 325A, 350A, 400A, 450A, 500A, 600A, 700A and 800A.
Manufacturer Test Data Note
The manufacturer states that the test data contained in the RS309-MF selection specification were measured under DC test conditions. The wiring method and test conditions reference IEC 60269 and UL 248.
Browse SINOFUSE RS309-MF Products
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Technical Sourcing Support
Apexon Solutions provides sourcing support for SINOFUSE RS309-MF fuses and other industrial electrical protection components. We support industrial buyers with model identification, specification review, technical cross-reference, and international sourcing coordination.
For RS309-MF availability, technical information, or quotation requests, contact Apexon Solutions.