RoyJ wrote:

In spite of what the others have said about synchronizing things, in
theory it can be done. In practice, with small generators, NOT A CHANCE!

consider: first unit is running at full speed and half power into a
load. Disconnect the field windings on the second unit, bring it up to
speed, match the speeds as precisely as you can. Slowly bring the field
current. If (when) the 2nd unit is going a bit too slow, generator #2
will act like a motor and try to speed up engine #2. And the additional
load on generator #1 will tend to slow that engine down. Similarly, if
#2 is too fast, it will act like a generator and slow down engine #2,
etc etc. Bringing the field current up slowly will allow the units to
find a compromise condition where both are putting full power into the
load. The power company does this all the time for their generators.

In practice, the governors on these units are way to unstable (about 2
orders of magnitude!) to keep the synchronizing currents within
reasonable bounds. You will blow the breaker almost instantly.


It can indeed be done, and the low rotating mass of the small generators
actually makes it easier to do and more tolerant of phase mismatch on
sync-up. Go read the thread on alt.energy.homepower I referenced,
particularly the posts from Neon John, a credible poster who parallels
two $100 Chinese generators to run an A/C unit for his semi.