A Guide to Standby Generator Onboard Circuitry

Standby generators provide backup power during outages, automatically kicking in to keep your essential appliances running. Understanding the core components within the onboard circuitry can offer a general idea of how these generators function.

Here’s a breakdown of the key electrical parts:

  • Engine and Alternator: This is the heart of the system. The engine, fueled by gasoline, propane, or natural gas, converts chemical energy into mechanical energy. The alternator then takes this mechanical energy and uses it to rotate a shaft connected to magnets within a stator. This rotation induces an electric current in the windings of the stator, producing AC (alternating current) electricity.
  • Automatic Voltage Regulator (AVR): Fluctuations in engine speed can cause variations in the output voltage of the alternator. The AVR acts like a voltage stabilizer, constantly monitoring and adjusting the alternator’s field current to maintain consistent AC voltage output. This ensures safe and reliable power for your appliances.
  • Transfer Switch: This vital component acts as a traffic director for your electrical supply. During normal operation, the transfer switch connects your home to the utility grid. When a power outage occurs, the transfer switch senses the drop in utility power and automatically starts the standby generator. Once the generator reaches operating voltage, the transfer switch seamlessly switches your home’s electrical circuits from the utility grid to the generator’s output. When utility power returns, the transfer switch reverses the process, switching your home back to the grid and stopping the generator.
  • Control Panel: This acts as the brain of the standby generator. It houses various circuits and relays that control the entire operation. The control panel monitors various parameters like engine speed, oil pressure, battery voltage, and generator output. In case of any abnormality, the control panel can shut down the engine to prevent damage. It may also include features like automatic start/stop based on pre-set timings or utility power status.
  • Battery and Battery Charger: The battery provides the starting power for the engine when a power outage occurs. The battery charger keeps the battery topped up and ready for use, typically drawing its power from the utility grid when available.
  • Safety Devices: Standby generators incorporate various safety features to ensure secure operation. These may include overload protection to prevent circuit damage, low oil pressure shutdown to safeguard the engine, and over-temperature shutdown to prevent overheating.

Additional Notes:

  • This is a simplified overview, and the specific circuitry may vary depending on the manufacturer and model of the standby generator.
  • For in-depth information and troubleshooting, it’s always best to refer to the user manual provided by your generator’s manufacturer.

If you’re considering purchasing a standby generator, consulting a qualified expert can help you determine the right size and features for your needs. They can also ensure proper installation and ensure your home’s electrical system is compatible with the generator’s output. 

If you need to consult a local expert, James Bryant of Back Up Power LLC has a degree in  Electrical Engineering Technology, a Master Electricians License, a Class A Contractors license and 30+ years of experience in the electrical industry. 

Call now at (540) 968-6440 or email james@backuppowerllc.com.