Siemens Industry 66BA3

The Model 66 Amplifying and Reducing Relays are used to increase or decrease control-circuit pressure signals. Its input pressure, acting upon the effective area of the top diaphragm, produces a force that is balanced by the force produced by the output pressure applied over the effective area of the lower diaphragm. Any imbalance in these opposing forces will operate the plunger, increasing or decreasing air supply to the output chamber. (The amplifying or reducing ratio is fixed by the ratio of input-to-output diaphragm areas.) An increase in input opens the pilot valve to admit supply air directly to the output. A decrease in input opens the exhaust port to exhaust air from the output.

Product Highlights

• Input to Output Ratio:
  • Amplifying: 1:3
  • Reducing: 3:1
• Air Consumption: 0.12 scfm maximum
• Flow Capacity: .2 scfm minimum
• Linearity:±1% of output span
• Materials of Construction: Brass, aluminum, stainless steel, and Neoprene
• Maximum Output Pressure: Within 0.1 psi (0.7 kPa) of supply
• Minimum Output Pressure: Less than 0.4 psig (3 kPa) with zero output
• Operating Temperature: -40 to 180°F (-40 to 82°C)
• Overrange Limits: 100 psig (690 kPa) at any connection
• Range Limits: 80 psig max. for input or output - whichever limits
• Reproducibility: Within 0.02 psi (0.15 kPa)
• Response Level: 0.2" H2O (5 mm H2O)
• Supply Pressure: Normal: 20 psig (140 kPa) Maximum: 80 psig (550 kPa) Minimum: 1 psi (7 kPa) above maximum required output
• Zero Error: 66BA6: ±0.36 psi (2.5 kPa)All Others: ±0.24 (1.5 kPa)