AMPTEC Research · Ruggedized Igniter Testers
640N
Military-grade ruggedized, waterproof failsafe igniter tester
The 640N is a ruggedized failsafe igniter tester for military ordnance programs. It measures the resistance of explosive bridgewires (EBW), squibs, detonators and igniters without risk of firing them. A shielded Faraday cage and a waterproof rugged case make it suitable for rough field conditions. Evencat is AMPTEC's sole distributor in Taiwan.
Overview
The AMPTEC 640N is a ruggedized mid-range failsafe igniter tester developed for military ordnance and aerospace and defense work. It measures bridgewire resistance on squibs, igniters, explosive bolts, rocket motor squibs, automotive airbag initiators and other pyrotechnic devices without initiating them. A self-contained DC milliammeter and test resistors are built in, and four ranges of 20Ω, 2000Ω, 200KΩ and 2MΩ are provided. The shielded Faraday cage keeps external electromagnetic interference out, and the failsafe current is hard-limited to prevent accidental initiation. AMPTEC lists the 640N with multiple safety approvals, and it is catalogued under NSN 6625-01-642-8232. The waterproof rugged case carries a 4½ digit LED display and rechargeable NICAD batteries, giving field durability with laboratory-class accuracy (±.02% of reading & range). Note that the 641N and 641RS offer the same protection in a lighter case; the 640N remains the choice where an NSN or an existing procurement spec names it.
Key specifications
| Ranges | 20Ω / 2000Ω / 200KΩ / 2MΩ |
|---|---|
| Nominal current | 5 mA / 50 µA / 0.5 µA / 0.05 µA |
| Failsafe current | 8 mA / 150 µA / 1.5 µA / 0.15 µA (8 mA max) |
| Resolution | 1 mΩ / 10 Ω / 10 Ω / 100 Ω |
| Accuracy | ±.02% of reading & range (2MΩ range: ±1% of reading & ±.2% of range) |
| Display | 4½ digit LED |
| Terminals | Trident |
| Temperature coefficient | ±.002% per 15°C |
| Operating temperature | 0° to 50°C |
| Max input voltage / open circuit voltage | 250 VDC / 1.6 VDC |
| Power | 4 rechargeable 5AH NICAD batteries |
| Dimensions / weight | 13.4″ (L) × 11.62″ (W) × 6″ (D) / 9.8 lbs |
Features
Failsafe design
The failsafe current is hard-limited (8 mA max), so squibs, detonators and explosive bridgewires cannot be initiated during measurement.
Shielded Faraday cage
A shielded Faraday cage keeps external electromagnetic interference out, for stable resistance readings in fuel-laden and electrically noisy areas.
Military-grade waterproof case
The waterproof rugged case is built for harsh field and ordnance work, standing up to the shock, water and dust of transport and deployment.
Four ranges
Ranges of 20Ω, 2000Ω, 200KΩ and 2MΩ with ±.02% of reading & range accuracy cover most igniter measurement needs.
Self-contained measuring system
A built-in DC milliammeter and test resistors, a clear 4½ digit LED display and rechargeable NICAD batteries support long sessions in the field.
Approvals
Built under ISO 9001:2015, UL-913 compliant, catalogued under NSN 6625-01-642-8232, and in service with NASA and the USAF.
Typical applications
Munitions and ordnance
Pre-installation inspection of missile and rocket motor igniters
Before a missile system or rocket motor enters the final assembly line, ordnance technicians use the 640N to confirm the resistance of explosive bridgewires (EBW) and detonators is within design tolerance. The 8mA maximum failsafe current keeps the test from initiating the device and protects the assembly crew.
Aerospace ground support
Depot-level testing of spacecraft pyrotechnic separation systems
NASA and USAF ground support teams use the 640N on the pad or in the maintenance hangar for depot-level resistance measurements on pyrotechnic separation bolts and flare igniters. The waterproof ruggedized case and rechargeable NICAD batteries let it run on its own at an outdoor launch site with no external power.
EOD and safe disposal
Non-destructive safety confirmation at EOD sites
When handling unexploded ordnance or recovered igniters in the field, EOD teams rely on the 640N's Faraday cage shielding and four ranges (20Ω to 2MΩ) for non-destructive resistance checks on fuze bridgewires. They confirm continuity or short-circuit risk while the induced current stays below the safe threshold, in line with UL-913 intrinsic safety rules.
Options and configuration
Tick the options you need; we will assemble the configuration list and carry it into the inquiry form.
Standard equipment (included)
Test lead and probe options
Charger option
Downloads
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