🔍 Key Concepts

• Parallel alternator operation – how reactive power (kVAR) is shared when machines are in parallel • Effect of field excitation changes on terminal voltage, reactive current, and power factor • Difference between changes in kW load (real power) vs. kVAR / power factor (reactive power) when machines are in parallel

💭 Think About

• When two alternators are in parallel and you change ONLY field excitation on one machine, are you mainly changing real power (kW) or reactive power (kVAR)? • If an alternator’s excitation is increased, does it tend to supply more reactive power (magnetizing current) to the system, and does that push its power factor toward leading or lagging? • What happens to the current and power factor of the other alternator when one machine starts supplying more reactive power?

✅ Before You Answer

• Be clear on the difference between speed / governor (kW sharing) adjustments and excitation / voltage (kVAR sharing) adjustments in parallel operation • Remember that increased excitation tends to increase the machine’s internal voltage and its share of reactive (not necessarily real) power • Check which power factor direction (leading vs lagging) corresponds to supplying reactive power to the system rather than absorbing it