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Npc’s Arc resistant ceramic is made by Zircon. A high tension air circuit breaker and electro magnetic switch. Arc resistance ceramic is a excellent arc extinguish material and it is able to protect other parts from the arc heating.
Pros
- Especially, suitable for direct current arc
- Fire resistance
- thermal shock resistance
- Mechanical strength
- Good electric insulation, withstand voltage
- Easy to absorb the arc heat.
- Dimensional accuracy
Fire resistance test（by Oxy-acetylene flame）
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（N-330 arc extinguishing ceramic made by zircon）
Note: Test piece is exposed by oxy-acetylene frame which is belched out from 1.75mm caliber nozzle and the frame is around 100mm length. exposing to the frame for 5 second by maximum temparture, and pausing for 10 second. The test is operated this cycle for 5 times.
Properties and stats
| properties | units | N-300 | N-330 | Experiment method | |
| Water absorption | % | 0.2 | 6.0 | JIS C2210 | |
| Porosity | % | 0.0 | 12.0 | ||
| apparent specific gravity | 3.2 | 2.7 | JIS C2210 | ||
| Bending strength | ordinary state | ㎏/㎝2 | 1000 | 250 | JIS C2210 |
| After heated by 500℃ | ㎏/㎝2 | 1000 | 250 | JIS C2210 | |
| Impact bending strength | ㎏-cm/㎝2 | 3.5 | 1.5 | JIS C2210 | |
| Thermal expansion coefficient | ×10-6 | 3.2 | 3.0 | 20~400℃ | |
| Break down voltage | KV/㎜ | 14.0 | 1.5 | JIS C2210 | |
| Volume resistivity | Ω‐㎝ | >1014 | >1013 | JEC148 | |
| Fire resistance | Excellent | Excellent | Oxy-acetylene | ||
| Arc-resistance | second | >420 | >420 | ASTM495 | |
| Strong point | Fine grain Strength |
Arc-resistance | |||
| Usefulness | Pleurum | Arc Barrier, etc | |||