Series-A3000

A3000 Photohelic® Switch/Gages for Pressure Measurement up to 25 psig

Bezel and front cover (with set point knobs and zero adjustment screw) removed to expose Photohelic® switch/gage set point mechanism. Cover is clear polycarbonate plastic.
Gage pointer and light shutter are mounted on helix and balancing counterweight. Shutter passes through slot in optical limit switch to expose phototransistors to integral infrared light source or mask them depending on applied pressure.
Light shield effectively protects phototransistors from strong outside light sources yet allows free pointer movement. It also gives interior a clean "finished" look.
Optical limit switches are used for reliability and long service life. Attached directly to set pointers, they are individually aligned to assure precise switching accuracy.
Semi-Flexible drive shaft connects to set point knobs.
Zero adjustment screw connects to screw in cover to adjust zero pressure reading.
Plastic enclosure protects electronic components and electrical connections.
Polycarbonate connection or terminal board is self-extinguishing.
Glass epoxy printed circuit boards for durability and permanence.
Load relays are DPDT with latching feature for maximum application versatility.
Electronics are designed to operate on 50/60 Hz, 120 volt current with 10% over or under voltage. Special units for other voltages are available.
Switch set pointers show switch settings at all times.
Spring loaded friction clutch prevents operator damage of set point mechanism.
3-in-1 instrument allows the reduction of several instruments with one product, saving inventory, installation time and money.
Patented design and 1% full scale dead band provides quick response to pressure changes means no delay in switching and chatter-free operation.
A wide range of models that can meet pressure measurement specifications from low to very high.

See Product Overview

Series-A3000

From ^TWD 26,794

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More Variations Available

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Data Sheet

Product Overview

Accuracy Detail ± 2% of FS at 70°F (21.1°C). ± 3% on -0 and ± 4% on -00 models
Dial Depth 8.25 in
Dial Dia 4 in
Dial Outer Diameter 5 in
Division 0
Electrical Connection Screw Terminal
Materials, Wetted Consult Factory
Media Compatibility Clean dry air / inert gas, HVAC / room air, Inert / non-reactive gases, Helium, Nitrogen, Non-Corrosive Dry Gases
Mounting Orientation Vertical Diaphragm
Operating Temperature, Max 120 °F
Operating Temperature, Min 20 °F
Measurement Pressure Type Differential
Process Connection Size 1/8 in
Process Connection Type NPT Female
Proof Pressure -20 inHg to 25 psi
Repeatability ± 1%
Series ID Series-A3000
Set Point Adjustment Adjustable Knobs
Supply Power Note 120 VAC, 50/60 Hz; 240 VAC and 24 VAC power optional
Supply Power Type AC
Supply Voltage 120 Vac
Switch Note Each set point has 2 form C relays (DPDT). 10 A @ 28 VDC, 10 A @ 120, 240 VAC
Switch Rating 10 A @ 28 Vdc, 10 A @ 120, 240 Vac
Switch Type (2) DPDT
Weight 4 lb

Supported Applications

The Series A3000 Photohelic® Switch/Gage is a versatile 2-in-1 instrument that combines the time-proven Magnehelic® differential pressure gage with low/high pressure switches. It measures and controls positive, negative, or differential pressure of air and other non-combustible, compatible gases, and the gage reading is unaffected by switch operation.

Because switch set points are adjusted with knobs on the face and the housing is molded from clear polycarbonate plastic, the series is well suited to filter monitoring, fan and blower control, cleanroom and HVAC pressurization, and general process pressure alarm or shutdown duties. On dual-scale air velocity (AV) models the instrument can also be used with a pitot tube to read air velocity in FPM. The Photohelic switch/gage may be used in an Underwriters Laboratories approved industrial control panel when the usage conforms to UL specifications for the acceptance of unlisted components.

Operating Conditions & Performance

The gage provides an accuracy of ±2% of full scale, with ±3% on -0 models and ±4% on -00 models. Switch repeatability is ±1% of full scale, and the dead band between make and break is 1% of full scale or less.

Temperature limits: -6.67 to 48.9°C, with a low temperature option available.
Pressure limits: standard models rated to 25 psig; the MP option extends this to 35 psig and the HP option to 80 psig.
Switch type: each set point has two Form C relays (DPDT).
Electrical rating: 10 A @ 28 VDC, 10 A @ 120, 240 VAC.
Power requirements: 120 VAC, 50/60 Hz; 240 VAC and 24 VAC power optional.
Process connection: 1/8" female NPT.

Screw terminals are used for electrical connections, and the instructions specify 75°C copper conductors only. The instrument presents a 101.6 mm dial face with a 127 mm outside diameter and an 8-1/4" overall dimension, and it weighs 4 lb (1.81 kg). The diaphragm must be mounted in the vertical position; consult factory for other orientations. Compliance is declared to CE, CSA, and UL.

Configuration Options

Models differ chiefly by pressure range, engineering unit, and switching options. Ranges are offered in several unit families so the gage face can be matched directly to the application:

Inches of water column and zero-center inches of water ranges for low-pressure air work.
Millimeters and centimeters of water ranges for metric low-pressure work.
Pascal ranges from 0-60 Pa to 0-750 Pa, and kilopascal ranges from 0-1 kPa to 0-30 kPa.
Dual-scale air velocity (AV) models that read both differential pressure and air velocity in FPM when used with a pitot tube.

Switching behavior is configurable through factory circuit styles and ordering options: single-relay activation on increase or decrease, medium- and high-pressure builds, tamper-proof knobs, and remote mounted relays.

Key Product Differences

Models are ordered as A3000-<RANGE> with optional suffixes (for example, A3000-00, A3000-6MM, A3000-1KPA, A3000-60PA). The following suffixes tailor the build: