Synchronizing 2 AC generators

That is tricky. If you want to connect the 2 gens to a 60 Hz system, considering the small power of the generators (6 kW each) you can just spin them a bit and connect to the system like any electric motor, one at a time (very rough way to connect a generator). the system will take care of the frequency. What you can control is the injected power. If the system frequency is not maintained by large generators but by your small generators than the first generator can be connected directly without problem, the second must be synchronized with the previous. To be able to synchronize : - the voltage must be the same - the frequencies must be the same - the angle between the voltages of corresponding phases (system and generator) must be as close to zero as possible. The measuring instruments you can find at shops for electrical measurement equipment. PS: I remembered that during engineering laboratories I synchronized a generator with the system using two frequency meters-to match the frequency of the generator with the frequency of the system and 3 voltmeters:one measuring the generator voltage(phase A and phase B connected), one measuring the system voltage (phase A and phase B connected) and one for matching the voltage vectors (Phase C-Phase C connected; When it measured zero voltage the voltage vectors are in phase).

Thank you. It is just in case for power outage. Do you think they will phase up easily? I thought of maybe coupling the shafts at the right angles? If I can avoid this, it should be great.

Do an internet search on the "Dark-Lamp Method" for synchronization. You'll be able to sync your small gennies for a few bucks worth of light bulbs.

They are just 2 small craftsman generators on wheels. And 1 is too little to spin the AC around or to do some occasional welding. Thank you. D.

My advice: Don't try to synchronise these 2 gensets!

I am sure that their governors are not accurate enough to maintain the synch properly and Especially if you try to Synch with the mains (That will be the end of the gensets).

To synch them together only (without the mains), it will be too combersome. Separate the load into two circuits and feed each with a different unit. The only drawback is going to be for any single load that exceeds the 6kW or even 5 kw. if you have small loads, you can combine them judiciously to be able to split the circuit into 2. You can still supply both loads from the same Mains when available.

Otherwise, get a suitable 12kW set and it will take more load confortably than the 2 units even synchronised.

Thank you. Part 1 seems pretty evident to me too. Don't you think that with coupling the generators, so that the phase is perfect aligned and synchronized, the two will not work together? I wonder what the governors will do. I also don't know if it is possible. Probably the generator uses also the crankshaft bearing. I'll bring this project to a lower priority.

Another option would be to rectify both generators and feed an inverter. That should do the trick very nice and tidy.

In this case you don't need to synchronize the generators.