The phrase "automatic warning system" is correct and usable in written English.
It can be used in contexts related to safety, technology, or alert mechanisms that operate without human intervention.
Example: "The automatic warning system activated when the temperature exceeded the safety threshold."
Alternatives: "automated alert system" or "self-activating warning system".
The train's automatic warning system was working, the inspectors found.
In response Waze introduced an automatic warning system for Rio users when they choose a route through high-crime areas.
Railtrack chief executive Gerald Corbett dismissed a report from the Health and Safety Executive in April that a misaligned piece of track could have shaken the Thames train so violently it caused the automatic warning system to malfunction.
He is going to demonstrate with the automatic warning system equipment that if you hit the receiver hard at the right moment it sounds a bell not a horn.
It eventually found a solution: A radio-based automatic warning system.
The Metro drivers do not have the benefit of automatic warning system (AWS) or train protection and warning system (TPWS) available to the mainline train drivers on the same route.
Your spacecraft and spacesuit have automatic warning systems, fail-safes and redundancies, and the calm voice of Houston can be heard from down below, walking you through any glitches that emerge.
Problems in aircraft technical performance are often raised through automatic warning systems, and periods of activity tend to be discrete (for example, a 12-hour flight).
It also blames a lack of co-operation among the crew and a slow reaction to an automatic terrain warning system that warned pilots they were flying too low.
Because the train was close to the epicenter, an automatic early warning system did not work, Masaki Ogata, managing director of JR East, the rail line, told reporters.
