# What is a good circuit model for an AC generator?

A very simple electrical AC generator can be made by spinning magnets around a fixed stator coil. The changing magnetic field induces current in the stator winding.

It would seem that at a fixed frequency, this system is best modeled as a current source with some series resistance and inductance. Is this a good model?

If so, it would suggest that the behavior of the system in an open-circuit scenario would be to generate a very high voltage at the output pins with zero current flow. Conversely, in a short circuit scenario, it would run a fixed amount of current through the loop which would be dissipated as heat in the series resistance (stator wires).

• Change in magnetic field induces a voltage as per Maxwell's equations. See the third equation in the table.
– AJN
May 13 at 16:44
• @AJN, so more of a voltage source with series inductance and resistance? May 13 at 17:02
• That seems correct. Inductance would be larger than resistance. And since a short-circuit has high voltage over low impedance means large current, which will damage generator. Same for an AC motor. May 13 at 17:24
• No - it is a VOLTAGE source with series resistance and inductance. A current source would give infinite voltage on no-load. May 13 at 18:48
• Yes, voltage source. I swear I read voltage source. May 13 at 21:58 