dual generator switchgear

[cschuerm]

Howdy all.  I've been working away on my "new and improved" backup power system and thought I'd toss something out for comment.  I have two generators.  The first is a big, industrial diesel.  It's full auto everything.  I've installed a fancy controller with autostart and complete monitoring.  It's connected to an Asco 7000 series transfer switch with all the bells and whistles.  The second generator is my trusty listeroid which some of you may remember from the trailer mount rig I built.  It's now been removed from the trailer and installed in my shop.  The goal is that the big generator will be the fully automatic standby power, but the listeroid will be there if I anticipate an extended outage (like our last big ice storm with no power for two weeks) since I won't want to feed the big beast for many days.  I've been contemplating various ways to transfer between the two generators.  If I wanted to spend the extra money on a second transfer switch, the Asco has a "sync before transfer" feature that looks like I could bring the lister  online and have the switch do a bumpless transfer when it came in sync with the big one.  I also have several good NEMA4 sized starters that I could interlock together and use as a switch, but I'm thinking it would be best to either be in sync or to allow the power to briefly go away before switching.  Could also just use a simple manual switch.  Anyone have any thoughts or have done something similar?
Chris

[Jedon]

If you are hand cranking the lister anyway why not just use two 50A breakers with an exclusive lock thingy ( I know I'm being super technical, a friend who is an electrician gave my the metal bits that fit in between the breakers. ). Well that's what I do anyway, not that I have a fancy auto anything generator, just the Lister SR2 and the Metro 6/1.

[rcavictim]

I like the simplicity and safety of having a BAR (big assed receptacle) representing each generator and a BAP (big assed plug) representing your load.  You can then easily accomodate an additional BAR to represent the utility.  This means fully manual switching but foolproof and no way to backfeed the mains or another possibly out of sync generator.

[Tug]

I would use a 60 amp generator manual transfer panel.....
You could wire both generators to the breakers with the interlock devise and have your power coming out of a breaker in the bus...
The panels usually switch your neutrals as well...
Cheers
Tug
http://downloads.eatoncanada.ca/downloads/Advanced%20Residential%20Products/Product%20Guide/Manual%20Transfer%20Switches%20-%20BR00407002K.pdf

[Crofter]

I have watched a number of on the fly switch overs from one large generator to another without dropping the load. It was an improvised light across the two generators and the unloaded generator was manually coaxed up in revs till the light went out indicating the two heads were in phase and then the transfer switch was thrown. Sure as heck not approved procedure as bad, bad things would have happened if someone boo booed! It saved having to go around the campsite to reset things in the different bunkhouses and service buildings. Proper fully automated systems are a whole heck of a lot more complicated and expensive. I think "Listeroid" would likely never be mentioned in their literature!