I started with a present of an old 4-frame extractor made a 100 years ago.
then I got a 4-frame hand-cranked one. Used it only one year, cause
then I got a 6-frame self-reversing extractor from a friend - till I could afford a larger one. He had been extracting 300 hives with it. It runs for about 4 minutes on flower-honey. it is a matter of timing, really.
Now I got a 12-frame reversible (it holds two combs each in a pocket) which does the job in half the time. it can extract in 4 minutes, too, if honey will flow easily. We got 75 hives right now. It can do more. I won`t need another one. It yields up to 24 kg of honey in 5 minutes. this amount has to be handled!
BUT:
If the extractor stands still during work, there is one of two things wrong: either the time needed to uncap or move boxes to the uncapping procedure. or you can`t sieve or whatever the honey not fast enough.
so the size of the extractor is one thing. the timing of in and out is just as crucial.
The 12-framer we got now was standing still too much, I knew that in advance. And knew I had to refine the in and out so it won`t stand still other for unloading and loading. I hope I can have it humming continuously this season.
as I figure you guys are usually using radial extractors (mine is tangential), the diameter of the drum is a limiting factor. radial extractors have to have a certain size for good results and little breakage of comb. if using comb which has been bred in, this doesn`t matter much. But for good tasting honey, "virgin" comb is better and they tend to break in a too-small-radial extractor.
or the honey won`t come out enough for satisfaction, if you can`t speed it up more.
I went for the tangential one cause we got a lot of forest-honey, which is not so very fluid...
hope that helps.
I heard: 3 feet or a tad more would be minimum for good results for radial extractors. larger is better. but being able to handle - I don`t know - 100 pounds of honey running out of the machine in a matter of minutes should be considered.