What Is a Standby Generator and How Does It Work?
By John Karbowski · November 26, 2024
Power outages can halt operations, damage sensitive equipment, and cost businesses thousands of dollars per hour in lost productivity. A standby generator is the reliable solution — automatically switching on within seconds of a utility failure to keep your facility powered until normal power is restored.
What Is a Standby Generator?
A standby generator is a permanently installed backup power system that automatically starts and transfers electrical loads when utility power fails. Unlike portable generators, standby units are wired directly into your building's electrical system through an automatic transfer switch (ATS). They run on natural gas or diesel and can power an entire facility or just critical loads.
How a Standby Generator Works
Utility Failure Detection
The automatic transfer switch continuously monitors utility power. When voltage drops below acceptable levels for more than a few seconds, the ATS signals the generator to start.
Generator Start Sequence
The generator engine starts automatically. Within 10–30 seconds (depending on the system design), the generator reaches operating speed and stable voltage output.
Transfer of Loads
The ATS disconnects from utility power and connects your electrical loads to the generator. This happens automatically without any manual intervention.
Utility Power Restoration
When utility power returns and stabilizes, the ATS transfers loads back to utility power and shuts down the generator after a cool-down period.
Standby Generator Sizing
Proper sizing is critical. An undersized generator won't carry your loads; an oversized generator runs inefficiently and can damage itself through wet stacking. Southern Electrical Services performs detailed load calculations to determine the right generator size for your facility — from small commercial units to multi-megawatt industrial systems.
- Calculate all critical and non-critical loads
- Account for motor starting surge currents
- Plan for future load growth
- Consider fuel type and storage requirements
- Size the automatic transfer switch correctly
- Evaluate paralleling options for large facilities
Standby Generator Installation in Houston
Southern Electrical Services installs and services standby generators from small commercial units to systems up to 2 megawatts. Contact us for a free site assessment.