Overview

The AMPTEC 630ES is a ruggedized mid-range digital failsafe ohmmeter for in-circuit resistance testing of military munitions and pyrotechnic devices, built on the proven 620ES circuit. It offers four ranges of 2Ω, 20Ω, 200Ω and 200KΩ, a 4½ digit LED display and 4-wire Kelvin terminals, and resolves 100µΩ on the 2Ω range. Reading accuracy is ±0.02% with a temperature coefficient of only ±0.002%/°C, so readings stay stable across the 0 to 50°C operating range. The 8mA maximum failsafe current, self-contained DC milliammeter and Faraday cage shielding keep the test safe on fuzes, bridgewires, explosive bolts, rocket motor squibs and automotive airbag initiators. The rugged waterproof case is compact for its class, and four rechargeable 5AH NICAD batteries power it through harsh field and tactical work. It is UL-913 compliant, built under ISO 9001:2015 and in service with NASA and the USAF. When ordering, choose a lead set (the 630-300 Kelvin clip set is the usual pick) and the 630-DC charger.

Key specifications

Ranges	2Ω / 20Ω / 200Ω / 200KΩ
Resolution	100µΩ (2Ω range) to 10Ω
Reading accuracy	±0.02% of reading; ±0.02–0.05% of range
Nominal test current	5mA (2Ω / 20Ω), 500µA (200Ω), 0.5µA (200KΩ)
Failsafe current	8mA max
Display	4½ digit LED
Terminal type	4-wire Kelvin
Temperature coefficient	±0.002% per 1°C
Operating temperature	0–50°C
Dimensions / weight	11.5" × 13.5" × 6" / 12 lbs
Power	4 rechargeable 5AH NICAD batteries
Max input voltage / open circuit voltage	250 VDC / 1.6 VDC

Features

Failsafe current limiting

An 8mA maximum failsafe current plus Faraday cage shielding keeps tests on fuzes, bridgewires and similar sensitive devices safe.

High resolution and accuracy

The 2Ω range resolves 100µΩ, reading accuracy is ±0.02%, and the temperature coefficient is only ±0.002%/°C.

Ruggedized waterproof case

A rugged, waterproof and reasonably compact case built for military ordnance programs and harsh field and tactical work.

4½ digit LED and 4-wire Kelvin

A clear 4½ digit LED display and 4-wire Kelvin terminals remove lead resistance from the reading.

Rechargeable battery power

Four rechargeable 5AH NICAD batteries, plus a self-contained DC milliammeter and test resistors, so nothing external is needed on site.

Wide device coverage

In-circuit testing of fuzes, squibs, explosive bolts, rocket motor squibs, automotive airbag initiators and other pyrotechnic devices.

Typical applications

630ES routine initiator safety verification at a field ammunition depot

Military munitions

Routine initiator safety verification at field ammunition depots

During ground munitions preparation, ordnance technicians use the 630ES to confirm continuity of explosive bridgewire (EBW) fuzes, checking that the firing circuit conducts within the allowed current and has no short-circuit risk, so nothing fires by accident. The weatherproof compact case and four rechargeable NICAD cells let it run on its own in magazines, field positions and aircraft loading areas with no mains power.

Aerospace launch

Pre-flight testing of rocket and spacecraft ignition systems

NASA and USAF launch-site ground support teams use the 630ES during vehicle integration, measuring solid rocket igniter and separation bolt resistance through the 4-wire Kelvin terminals and accepting values inside the manufacturer's window. The ±0.02% accuracy and failsafe circuit keep the test current below the initiation threshold, as flight safety rules demand.

Harsh environments

High-reliability measurement on ship decks and overseas forward bases

Having passed MIL-STD-810F environmental testing, the 630ES is at home on a ship's deck, at a desert forward base or in hot, humid regions. The weatherproof case keeps salt fog and dust out, and the built-in DC milliammeter and test resistors let technicians pass or fail fuzes and electro-explosive devices on the spot with no extra calibration gear, reducing dependence on the supply chain.

Options and configuration

Tick the options you need; we will assemble the configuration list and carry it into the inquiry form.

Standard equipment (included)

4½ digit LED digital displayHigh-brightness LED, readable in any lighting

4-wire Kelvin terminalsRemoves lead resistance error for true four-wire measurement

Four measurement ranges2Ω, 20Ω, 200Ω and 200kΩ, failsafe test current 8mA max

Faraday cage designMetal shielded enclosure that blocks static interference, as military explosive-safety practice requires

Waterproof weatherproof aluminum caseTough and durable, for outdoor and harsh-environment military sites

4 rechargeable D-cell 5AH Ni-Cad batteriesFour heavy-duty nickel-cadmium rechargeable cells fitted as standard for long runtime

Built-in self-calibrating DC milliammeter and test resistorsSelf-contained, so a full check can be run with no extra external equipment

Test lead and probe options

630-300 | 4-wire Kelvin clip test lead set48" shielded leads with gold-plated Kelvin clips, ½" jaw opening, for wires, pins and conductors up to ½" in diameter; the recommended standard choice 630-304 | 4-wire banana plug Kelvin test lead set48" leads terminated in 4-wire banana plugs, for standard test benches 630-305 | Twin single banana plug test lead setRed and black single-conductor leads, for jobs that need separate positive and negative probes 630-401 | Single-point Kelvin probe set4-wire single-point Kelvin probes for circuit board solder joints and small contacts 630-403 | Mini probe setFine mini probes for tight spaces and very small contact points 630-405K | Heavy-duty spiked Kelvin probe setHeavy-duty build; the spiked tips pierce oxide or coatings for reliable contact 630-405S | Heavy-duty spear Kelvin probe set (10 ft)Spear probes with 10 ft reach, for distant test points or large test items 630-406S | Heavy-duty spear Kelvin probe set (5 ft)Spear probes in the 5 ft version, lighter and easier to carry 630-408J | Heavy-duty Kelvin clamp jaw test lead setWide-opening clamp jaws for thick cables or large conductors

Power and storage options

630-DC | Slimline AC battery charger115VAC to 9VDC charger for the built-in Ni-Cad pack, for base or maintenance-shop use 630-BAT | Replacement D-cell Ni-Cad battery setFactory set of 4 D-cell 5AH nickel-cadmium rechargeable batteries, as spares or replacements 630-100 | Padded carry case for bonding ohmmetersPadded case that protects the meter in transit and storage 600-PC | Pelican case for test leads and probesRugged Pelican protective case for keeping lead sets and probe kits together

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630ES