A pressure-activated electrical switch manufactured by Furnas (now Siemens) is a component used in air compressors to regulate the motor’s operation based on tank pressure. When the pressure inside the tank drops below a preset minimum, the switch closes, powering on the compressor motor. Once the pressure reaches a specified maximum, the switch opens, turning the motor off. This cycling action maintains pressure within a desired range. As an example, a specific model might be set to turn on the compressor at 90 PSI and turn it off at 120 PSI.
The device’s importance lies in its ability to automate the air compression process, ensuring a consistent and readily available air supply. This automation is crucial for various industrial and commercial applications that rely on compressed air, from powering pneumatic tools to operating machinery. Historically, these switches provided a safer and more efficient alternative to manually controlled systems, preventing over-pressurization and conserving energy by only running the compressor when necessary.