But each don't only pull from the leg by itself... it takes two to tango.
So, it will have be connected 1-2 2-3 and 3-1... basically all of them share the load.
Are you sure those panels are 50 amps each? That would be a 10kw panel.
That was just an example. The big dryer we did was a Hix 4816 and started as a 90 amp 3-phase. In Single phase I believe we
basically ended up with a 200 amp service just for it.
I get what you're saying about each leg carrying 1/2 the load for two different circuits though. You're right The math probably works out to just less than double, but when you throw in a phase generator/converter for the belt & blower motors you're going to get some parasitic loss and I thought I'd say triple just to be on the safe side...
I think for most shops that don't have access to 3-phase, a
really big single phase circuit is probably not available either, or you may need to put an additional service in from the street just for the dryer. My two quartz flash-cures that we converted are now on 80 amp and 60 amp 220 circuits for the 20 x 32" and 20 x 24" respectively. The copper, junctions, breakers and Captire alone were over $1000 for the two runs, and my breaker box is right beside my press so it isn't a long run. I am lucky enough to have a good electrician friend who doesn't mind pulling circuits in an evening if I supply the pizza and beer. or I'm sure it would have cost another big chunk of change.
Mark, I'd probably suggest talking to Rich at M&R, or Winston. I run an old non-air Hix 24" belt with a 10' tunnel. (14' total length) It gets the job done and with small-medium sized images and careful folding we can do 40-45doz./hr through it without too much trouble. On big images or if we try to go faster it is the bottle neck. As a band-aid, we have an IR flash-cure that we can put over the belt at the in or outfeed which "sort-of" effectively gives us another 18" of tunnel and lets us speed up the belt a little bit. I run a 1.5 minute tunnel-dwell for plastisol and a 2 minute for WB/DC. both at 325F We could go faster with a higher temp, but you start potentially flirting with cure issues then. I have 400 amps of single phase in the shop and we're pretty much maxed out with all the equipment we have. The dryer pulls only 40 amps, the upgrade will be gas as we already have gas in the shop.
I had the same problem finding a big auto with all the features I wanted that wasn't 3-phase, and didn't need a big 3-phase air compressor, besides we wanted servo index AC heads. At first I thought we would need a big 3-phase convertor for the flash cures, but once my electrician and I looked into them and how they work, we realized with a couple of cheap parts and an hour or so of re-wiring we could convert them to single phase easily, so we did.
I've run a lot of Hix dryers, but I'm sure some of the other name brands have larger single phase units available, the biggest Hix does right now is a
3616 with an 8' tunnel at 50 amps 3-phase or 88 amps single.
A quick look at
M&R shows their biggest is the Radicure 36/6-4 (10') with a 6'tunnel at 53 amps 3-P and 89 amps 1-P. I'm betting there are larger units out there, just not a stock item, and as you can see, you're going to be well over 100 amps as soon as you go any bigger.
Sorry for the long winded reply, squeezing big equipment into a single phase shop is a subject dear to me
My quote from the city to get 3-phase into the shop was $27,000.00, just less than the cost of my used 12/14.