The gage mechanism is enclosed in a polycarbonate, break-resistant case and lens. A polished stainless steel bezel and O-ring seals help protect this rugged instrument from the external environment. The gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts have a self-cleaning motion to ensure electrical continuity.
The A25V-30 Vacuum Swichgage® is commonly used to measure loading of spark ignition engines through intake manifold vacuum. The gage can serve as an overspeed protection from sudden loss of load on the engine and can be used anywhere the vacuum source is compatible with port materials. A pulsation dampener is included with each Vacuum Swichgage® to help eliminate pointer flutter. The A25V-30 has a beryllium copper diaphragm, two adjustable limit SPST contacts (pilot-duty only, 2A @ 30 VAC/DC), and a 1/8-27 NPTM brass process connection.