Technical Introduction of 170M3666 High-Speed Fuse
1. One-Sentence Description
The 170M3666 is an American-style rectangular high-speed fuse with a micro-switch indicator, rated at 690V/700V and 630A, specifically designed to protect semiconductor devices.
2. Features
- Physical Characteristics: Size 1 (Type-FKE/115), length 136mm, width 53mm, height 25mm
- Status Indication: Integrated micro-switch for remote monitoring of fuse status
- Low Loss: Power loss at rated current is only 70W
- Dual Certification: Compliant with IEC 60269-4 standard and UL recognized
3. Core Technical Indicators
| Parameter | Value |
|---|---|
| Rated Current | 630A RMS |
| Rated Voltage | 690V(IEC)/700V(UL) |
| Breaking Capacity | 200kA RMS Sym |
| Pre-arcing I²t | 41,000 A²s |
| Total Clearing I²t (660V) | 275,000 A²s |
| Power Loss | 70W (at 630A) |
Note: The I²t value needs to be multiplied by the correction factor K according to the actual voltage (see the "Arc Voltage" curve)
4. The Story Behind the "Chip"
Although called a "chip", it is actually a melt structure with precision metallurgical technology:
- Silver or copper alloy melt is used, forming a multi-segment narrow-diameter structure through controlled etching technology
- The geometric shape of the melt is optimized by supercomputing fluid dynamics to ensure directional fracture within microseconds
- Quartz sand filler and special ceramic body work together to suppress arcs, achieving top-level breaking capacity of 200kA
5. Design Concept
"Three Lows and One High" principle:
- Low Arc Voltage: Peak arc voltage < 1.5 times the working voltage (at 15% power factor), avoiding damage to the IGBT gate
- Low Energy Passage (I²t): Total clearing I²t is 15-30% lower than competitors, reducing semiconductor thermal damage
- Low Power Consumption: 70W loss is 40% lower than traditional fuses, saving cooling costs
- High Cycle Life: Withstands more than 20,000 load fluctuations (△T≤80℃)
6. Application Scenarios
- DC Common Bus: 48V/400V DC power distribution protection in data centers
- Inverter Protection: Backup protection for wind power converters and mining hoist IGBT modules
- Rectifier System: 12-pulse rectifier cabinets for electrolytic aluminum
- Special Power Supplies: Plasma cutting machines, induction heating power supplies
7. Unique Advantages
Dynamic Arc Suppression Technology (DAST):
- Segmented melt design combined with boric acid-impregnated quartz sand splits the arc into 300+ micro-zones within 3ms
- Achieves the world's lowest total clearing I²t value of 275,000 A²s for the same specification (at 660V)
- Reduces semiconductor damage rate by 22% compared to similar products (based on IEC TR 61912-4 data)
8. Essential Knowledge for Engineers in Selection
- Voltage Correction: When the actual working voltage is not equal to 660V, the formula applies: P actual = Γ t660y × K (K value see "Arc Voltage" curve)
- Derating Use: When the ambient temperature > 40℃, derate by 0.8% for each 1℃ increase
- UL Special Requirements:
- Cooper's special arc-extinguishing cover is required for 700V applications (model see P185)
- Parallel use is prohibited (UL standard single-tube current limiting)
- Failure Warning: The contact capacity of the micro-switch is only 0.5A, so an external intermediate relay must be used
Key Reminder: The size 1 170M3666 is not interchangeable with the size 2 170M5716 (same 630A). The latter is 26mm longer and has different heat dissipation requirements.
