I have two questions about reactive power. 1) I have read that the flow of reactive power is proportional to the magnitude of voltage difference between nodes. Could someone explain me this? 2) At the merchant vessel that i am working, if i increase the field excitation ( the current of generator's rotor ) the power factor increases. Why this happens? Thank you.

  • \$\begingroup\$ Could you clarify what you mean by nodes? Terminals? \$\endgroup\$ Commented Apr 1, 2016 at 13:56
  • \$\begingroup\$ the same meaning that nodes have in circuits, not terminals. I have read that in physics forum sitehttps://www.physicsforums.com/insights/ac-power-analysis-part-2-network-analysis/ \$\endgroup\$
    – veronika
    Commented Apr 1, 2016 at 14:01
  • \$\begingroup\$ The link does not go to anything appropriate. \$\endgroup\$ Commented Apr 1, 2016 at 14:08
  • \$\begingroup\$ go to physics forum and look for ac power analysis part 2 it is a very elegant analysis which i do not understand \$\endgroup\$
    – veronika
    Commented Apr 1, 2016 at 14:20
  • \$\begingroup\$ Power, and reactive VA, are proportional to voltage squared. \$\endgroup\$
    – Chu
    Commented Apr 1, 2016 at 14:41

1 Answer 1


The magnetic field in a synchronous machine is caused by the net effect of the field current and the armature current. Increasing the field current of a generator can either increase or reduce the power factor of the generator depending on whether the starting point is a leading power factor or a lagging power factor as shown below.

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