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Photohelic® Switch/Gages with 120, 240 or 24 VAC Power

Series AT3A3000

Flame-proof ATEX approved Photohelic® Switch/Gages, Series AT3A3000, function as versatile, highly repeatable pressure switches combined with a precise pressure gage employing the time-proven Magnehelic® gage design. The Photohelic® switch/gage measures and controls positive, negative or differential pressures of air and compatible gases. Standard models are rated to 25 psig (1.7 bar) with options to 35 psig (2.4 bar) or 80 psig (5.5 bar). Two phototransistor actuated, DPDT relays are included for low/high limit control. Easy to adjust set point indicators are controlled by knobs located on the gage face (accessible opening case after de-energizing instrument). Set points can be interlocked to provide variable dead band – ideal for control of fans, dampers, etc. Gage reading is continuous and unaffected by switch operation, even during loss of electrical power. Flame-proof ATEX enclosures are available in aluminum with glass window which allows for viewing of set point needles and process pressure. 

  • Service: Air and non-combustible, compatible gases
  • Wetted Materials: Consult factory
  • Accuracy: ±2% of FS at 70°F (21.1°C); ±3% on -0 and ±4% on -00 models
  • Pressure Limits: -20 in Hg to 25 psig (-0.677 to 1.72 bar). MP option; 35 psig (2.41 bar), HP option; 80 psig (5.52 bar)
  • Temperature Limits: 20 to 120°F (-6.67 to 48.9°C) LT low temperature option to -20°F available; Case: -58 to 140°F (-50 to 60°C) (Note: Product temperature limits differ from case)
  • Dial Size: 4" (101.6 mm)
  • Mounting Orientation: Diaphragm in vertical position
  • Set Point Adjustment: Adjustable knobs on Photohelic® gage face behind enclosure cover. Follow instructions and safety warnings to open cover
  • Switch Type: Each setpoint has 2 Form C relays (DPDT)
  • Repeatability: ±1% of FS
  • Electrical Rating: 10 A @ 28 VDC, 10 A @ 120, 240 VAC
  • Electrical Wiring: Screw terminals
  • Power Requirements: 120 VAC, 50/60 Hz; 240 VAC & 24 VAC power optional
  • Enclosure Rating: IP66. IP65 with option OPV, overpressure relief valve
  • Housing material: Aluminum
  • Finishing: Texture epoxy coat RAL7038
  • Pressure Connections: 1/8" NPT female brass (SS optional). In presence of acetylene it is necessary to use SS
  • Electrical Connections: Three 1/2" FNPT. Cable gland not included
  • Weight: 28.4 lb (12.9 kg)
  • Agency Approvals: CE 0470 II2 GD Ex d IIC Gb T6; -50°C ? Ta ? +60°C Ex tb IIIC Db T 85°C




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