TwinCitySparky
Senior Member
- Location
- Minnesota
I tried to make this short..
. I have an a low budget customer with a boat resto. shop. He has air files, DA's and paint guns being used. He moved the 20 HP converter/10 HP scroll compressor set-up from one shop to another and I wired them back in. Now he wants more air for some big upcoming projects. At first he was eyeing up some 30 HP scroll units - I said No WAIT! Gonna need way bigger converter, wiring etc.. Gotta research, dont buy yet! Next thing I know, he sais he called Quincy compressors and they say you can run another 10 HP scroll off that 20HP converter. So he finds a identical 10 HP scroll, buys it and calls me with the news. Service is 120/240 single phase. Scroll units start/stop automatically. Start inrush current (on existing set-up) is about 180 amps then it drops to about 45 amps per leg (combined converter/scroll load)- My reserch so far has found that you can combine loads like this with the 20 HP converter as long as both loads dont start at same time. (kinda figured that part) I was going to try to find some "off the shelf unit" to toggle power between the two pressure switches for that reason. Now he sais - lets wire these so first unit comes up to operating pressure, then ONLY when the first it is running and not keeping up will we have the second one start up and assist the first as it is running.
Is there such a control? Any other suggestions for verifying circuit size etc.? Thanks