What type of alarm activates to indicate the operation of the backup compressor in an instrument air source?

When a backup compressor is activated in an instrument air source system, it is essential for personnel to be aware of this operational change, which may indicate a potential issue with the primary compressor. A local alarm is specifically designed to provide immediate feedback at the site of the compressor system, ensuring that any changes in operation can be monitored closely by on-site personnel. This type of alarm is typically louder and more conspicuous to attract attention, allowing quick responses to operational shifts.

In contrast, a main alarm generally refers to an overall status alarm for a system and may not specify the exact change occurring. A source alarm tends to indicate something about the air supply itself, rather than the operational status of compressors. A warning alarm, while alerting personnel, usually refers to potential hazards or issues rather than the specific operational status of a backup compressor.

The designation of a local alarm in this context highlights its role in closely monitoring equipment functionality and ensuring that effective responses can be made promptly when the backup compressor is engaged.