On Wednesday 23 December 2015 13:22:14 David Christensen wrote: > On 12/23/2015 02:09 AM, Gene Heskett wrote: > > Ahh, but its being fed to a voltage-doubler with schottky diodes ... > > The PSU has a quite high > > capacitance input filter, and without this soft start timed power > > up, needs a 30 amp breaker in the service in order for the breaker > > to withstand the power up event. NEC says I can't service a duplex > > with more than a 15 amp breaker. The actual draw, once powered up, > > doesn't exceed 15 amps even with a vacuum cleaner being powered by a > > similar circuit enabled that is plugged into this same 4-plex. > > All part of a CNC milling machine setup. ... > > So, you want to connect a 120 VAC, 30 A CNC milling machine and a 120 > VAC, unknown current vacuum cleaner to a single 120 V 15 A branch > circuit. > > > I suppose you could read a power electronics book, and design and > build a device that accepts 120 VAC, 15 A steady-state input and > provides 120 VAC, 15 A steady-state output with the ability to output > much more current for short periods. Such a product may already > exist. If not, you might be able to make and sell them. > > > But, the KISS solution is obvious -- install a 30 ampere circuit > breaker, wiring, and receptacle for the CNC machine (or hire an > electrician to do so).
I am a CET. I do my own wiring on small projects. I even put a 200 amp service in here back in 2007 or so, putting the house as a subcircuit. The only thing I needed an electrician for was to do the drop seal break & disconnect, install a heavier drop to the new meterhead, the inspector came, liked what he saw and signed off, dead time to crimping the new seal a couple hours. Besides, powered up, spindle turning no load at 500 revs, the amprobe draw (w/o the vacuum) is around 2.65 amps, on either amprobe, I have 2. Its just the inrush that needs curtailed. Once thats done I'll swap the 30A breaker back out for a 20A I have laying there ready to be put back in where it came out. > > David And Qucs is still building. Sigh. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>