Question 6A350

Alternators, which generate AC power, are typically rated in Volt-amperes (VA) output. This is because VA represents the "apparent power," which is the product of the RMS voltage and RMS current the alternator can safely deliver, regardless of the load's power factor. * **A) Volt-amperes output:** This is correct. An alternator's physical limitations (winding resistance, insulation, core saturation) define the maximum current and voltage it can handle. These limits determine the apparent power (VA) it can supply. * **B) Watts:** Watts measure "real power" or "true power," which is the power actually consumed by the load and converted to useful work or heat. Real power (Watts) is equal to VA multiplied by the power factor (cos φ). Since the power factor varies with the type of load (resistive, inductive, capacitive), an alternator's capacity can't be solely defined by watts because it could deliver its full VA capacity but produce fewer watts if the load is highly reactive. * **C) Amperes:** Amperes measure current only. While current is a limiting factor, the alternator's rating also depends on the voltage it can produce.