The GCM-A2 protects air-cooled generators by continuously comparing generator cooling air against ambient room air using a highly sensitive submicron particle detector. By establishing the ambient air as a baseline reference, the system instantly confirms that any sudden spike in submicron particles originates from within the generator itself rather than the surrounding environment. If generator overheating occurs and particle counts exceed your customized, adjustable limits, the system triggers a differential alarm and closes protective contacts. For comprehensive safety, individual alarm contacts will also trigger independently if either the ambient air baseline or the generator cooling air spikes past safe operational limits.