How it Works: Standby Generators

In this "How It Works" column, a companion to Sean Groom's article, Standby for Power, (FHB#224), senior editor Rob Yagid looks into the way standby generators function. A control module monitors the utility power supply. When the sensor detects a disruption in power supply, the generator starts, and an automatic transfer switch changes the domestic power supply from utility to generator. When the sensor detects that the utility power is back, the transfer switch reconnects, and the generator shuts down. An alternator converts mechanical energy into electrical energy. Standby generators have either two-pole or four-pole alternators. A two-pole alternator typically produces electricity with an erratic current, but is generally available in less expensive generators. Four-pole alternators are more fuel efficient and typically much more expensive.