SINOFUSE RS309-MD Series AC/DC 500V High-Speed Bolt-Connected Fuse
The SINOFUSE RS309-MD Series is a cylindrical bolt-connected high-speed fuse family designed for demanding AC and DC protection applications. The series is rated at AC/DC 500V and covers a broad current range from 35A to 1200A.
According to the SINOFUSE manufacturer specification, RS309-MD fuses use the aR utilization category and combine compact construction, low I²t characteristics, high breaking capacity, and resistance to current surges, mechanical vibration, impact, wide temperature variation, and demanding road-vehicle operating environments.
RS309-MD Series Technical Specifications
- Manufacturer: SINOFUSE
- Series: RS309-MD
- Product Type: Cylindrical bolt-connected high-speed fuse
- Rated Voltage: AC/DC 500V
- Rated Current Range: 35A to 1200A
- Utilization Category: aR
- AC Breaking Capacity: 200kA
- DC Breaking Capacity: 50kA
- DC Time Constant: ≤15ms
- Performance Standards: UL 248 and IEC 60269
- Application Reliability References: ISO 8820 and GB/T 31465
- Certification: CE; UL certification applies to applicable models below 700A
- Environmental Compliance: RoHS
Key Features
- Compact cylindrical construction
- Low I²t characteristics
- High interrupting capability
- Resistance to current surges
- Designed to withstand strong mechanical vibration and impact
- Suitable for wide temperature-range environments
- Designed for demanding road-vehicle applications
Typical Applications
According to the manufacturer specification, the RS309-MD Series can be used in 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-MD Model Range
The RS309-MD family includes 27 current ratings from 35A to 1200A and uses multiple mechanical size codes to support different current levels and installation requirements.
| Size Code | Current Range | Models | Mounting Bolt | Recommended Torque |
|---|---|---|---|---|
| 3XA | 35A–60A | 35A, 40A, 45A, 50A, 60A | M8 | 12 ±1 N·m |
| 4ZA | 70A–100A | 70A, 80A, 90A, 100A | M8 | 12 ±1 N·m |
| 5ZA | 125A–200A | 125A, 150A, 175A, 200A | M8 | 12 ±1 N·m |
| 6ZA | 225A–400A | 225A, 250A, 275A, 300A, 325A, 350A, 400A | M10 | 21 ±1 N·m |
| 7ZB | 450A–600A | 450A, 500A, 600A | M10 | 21 ±1 N·m |
| 8ZB | 700A–800A | 700A, 800A | M12 | 28 ±1 N·m |
| 9RA | 1000A–1200A | 1000A, 1200A | M12 | 28 ±1 N·m |
Complete RS309-MD Current Ratings
Available RS309-MD ratings include:
35A, 40A, 45A, 50A, 60A, 70A, 80A, 90A, 100A, 125A, 150A, 175A, 200A, 225A, 250A, 275A, 300A, 325A, 350A, 400A, 450A, 500A, 600A, 700A, 800A, 1000A and 1200A.
Certification Note
According to the SINOFUSE manufacturer datasheet, the RS309-MD Series is CE certified and complies with the RoHS directive. UL certification applies to the relevant models below 700A. RS309-MD models rated from 700A through 1200A are specified as not UL certified.
Continuous Current Recommendation
The manufacturer recommends that long-term continuous operating current should not exceed 80% of the fuse rated current under the stated normal operating conditions.
Applications above the normal ambient temperature range or at elevated altitude may require parameter correction or current derating.
Operating Conditions
- Normal Ambient Temperature: -5°C to 40°C
- Permitted Ambient Temperature: -40°C to 120°C
- Product Storage Temperature: -40°C to 120°C
- Normal Operating Altitude: Up to 2000m
- Permitted Altitude: Up to 4500m with application evaluation and derating where required
- Pollution Degree: III
High-Altitude Applications
The manufacturer notes that higher altitude can affect thermal performance, air pressure, and insulation strength. For enclosed installations where internal temperature remains elevated, rated-current derating may be required.
The datasheet specifies a current derating guideline of approximately 2% to 5% for each 1000m increase in altitude under applicable enclosed operating conditions.
Vibration and Mechanical Resistance
The RS309-MD Series is designed to withstand vibration and mechanical impact. The manufacturer references GB2423.10-2008 4.1.2.6 and QC/T 413-2002 for vibration and shock performance.
The series is also described as suitable for rail-transit Class II application environments and road-vehicle body installation.
Manufacturer Test Data Note
According to the manufacturer datasheet, the published RS309-MD test data were measured under DC conditions. Test time constants and wiring methods reference IEC 60269 and UL 248.
Browse SINOFUSE RS309-MD Products
View available RS309-MD current ratings and individual product information in the complete series collection:
Browse SINOFUSE RS309-MD High-Speed Bolt-Connected Fuse Collection
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