Model 3-IS

Intrinsically Safe Survey Meter

Part Number: 48-3581

Features

• Intrinsically Safe
• Rugged
• 4-Range Analog Ratemeter
• Supports GM & Scintillation Type Detectors

This intrinsically safe general purpose ratemeter is patterned after Ludlum's best-selling Model 3. It was designed and tested to USA standards for intrinsic safety, permitting it to be used in potentially explosive atmospheres. The Model 3-IS can only be used with select detectors to sustain the intrinsic safety rating. Click the tab below to view compatible detectors.

Like the Model 3 before it, the 3-IS retains the well-deserved reputation for accuracy and long-lasting dependability. The cast aluminum instrument housing, with its separate battery compartment and accompanying metal handle, offer an industrial robustness and quality that promote long-lasting protection and instrument life. The front-panel controls include a rotary switch for selecting the four-decade range, instrument shut-off, and battery test, an audio on/off switch, a fast/slow response switch, and a count reset button. The analog meter comes in a variety of measurement ranges and units to support the external radiation detector selected.

A one meter (39 in.) straight type detector cable equipped with special connectors designed to prevent quick or accidental disconnection in the field is included in the price of the instrument.

• Specifications
• Compatible Detectors
• Options
• Documents
• Low Battery Note

• Specifications
• Compatible Detectors
• Options
• Documents
• Low Battery Note

Specifications

Application	Alpha, Beta, Gamma, or Neutron surveying in potentially explosive environments
Compatible Detectors	Supports select Ludlum radiation detectors (see Compatible Detectors tab) that can be purchased separately
Detection Range	Typically 0 to 200 mR/hr, or 0 to 500 kcpm
Linearity	Reading within 10% of true value with detector connected
Meter Dial	0 to 2 mR/hr, or 0 to 500 kcpm, BAT TEST (others available)
Meter	6.4 cm (2.5 in. arc), 1 mA analog type
Controls	Rotary Selector: Switches between: Instrument off, Battery check, Ranges: ×0.1, ×1, ×10, ×100 Response Switch: Toggles between FAST (4 s) or SLOW (22 s) from 10% to 90% of final reading Reset Push Button: Zero meter Audio Switch: Audio on/off, Built-in unimorph speaker, greater than 60 dB at 0.6 m (2 ft) Calibration Controls: Accessible from front of instrument (protective cover provided)
High Voltage	Adjustable from 400 to 1000 Vdc
Threshold	Fixed at 40 mV ± 10 mV
Temperature Range	-20 to 50 °C (-4 to 122 °F)
Power	Two each Procell PC1300 “D” cell batteries (see Warning note below). Batteries are housed in an externally accessible sealed compartment.
Battery Life	Typically greater than 2000 hours with alkaline batteries; battery condition can be checked on meter. (See Low Battery Note)
Construction	Cast and drawn aluminum with beige powder coat
Connector	Series "C" with locking screws to prevent inadvertent disconnection during operation
Size (H x W x L)	16.5 × 8.9 × 21.6 cm (6.5 × 3.5 × 8.5 in.), including handle
Weight	16 kg (3.5 lb), including batteries
Intrinsically Safe Certification	Class I, Division 1, Groups A, B, C, and D, T6 UL 61010-1 & CAN/CSA-22.2 No. 61010-1: Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use - Part 1: General Requirements UL 913: Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations CAN/CSA-22.2 No. 157-92 (R2002): Intrinsically Safe and Non-Incendive Equipment for Use in Hazardous Locations

WARNING: Use only Duracell Procell PC1300 1.5 V type "D" batteries. To reduce the risk of ignition of a flammable or explosive atmosphere, batteries must be changed only in a location known to be a non-hazardous area.

WARNING: When repairing this unit, substitution of components may impair intrinsic safety.

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Compatible Detectors

Detector	Type
Model 44-7	Alpha-Beta-Gamma End Window GM
Model 44-9	Alpha-Beta-Gamma Pancake GM
	Gamma GM With Beta Window
Model 44-38	Gamma GM With Beta Window
Model 44-2	Gamma 2.5 x 2.5 cm (1 x 1 in.) NaI(Tl) Scintillator
Model 42-41L	Neutron PRESCILA Proton Recoil Scintillator

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Options

Option	Description	Part Number
Transport & Storage Case - Small	Rugged, dust- and waterproof transport and storage case.	2311062

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Documents

• Data Sheet
• Product Manual
• CE Certificate
• Intrinsically Safe Certificate

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Low Battery Note

Use caution when using batteries that are low but are still above the LOW BAT mark with the detector in a high radiation field. When the detector is moved to a relatively high field the current to the detector may be high enough that the low battery steady audio is triggered. This low battery audio overrides the audio on/off switch, so this audio tone will be heard regardless of the position of the audio on/off switch. If the meter is turned to the BAT check position, the user can then see that the battery power level is below the LOW BAT mark. The radiation reading may or may not be correct when the low battery warning is active. There is no permanent harm done to the instrument. Replace the batteries with a fresh set of the approved type per the instrument manual. This problem is caused by the current limiting resistor necessary for the intrinsically safe rating, and the current drawn at relatively high radiation fields (for example: at or above approximately 100 mR/hr with the 44-9 pancake detector).

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