Re: Need a calculator that knows about coulombs
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
--
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Genes Web page <http://geneslinuxbox.net:6309/gene>
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