Ztrain, A workbook would probably be your best bet.
"Interpreting The National electrical Code"
is one I use in each new update. There are
other workbooks out there, but I'm more
familiar with this one by Truman C. Surbrook
and Jonathan R. Althouse. The...
qms006, The code used to say NO! on this one and it more
than likely still says Nyet! I have wire nutted wires to
short to reach a new lighting panel installation (in the
panel), but your position is pushing the envelope.
peterandersen, In working with motors and meggering, our
bottom line R was 1 megohm, anything less meant the
integrity of the insulation was lost. The cables are not
in such a harsh environment as the motor's windings.
The one cable with the low reading does indicate something
out of the...
majesus, Have you considered fusing it rather than trying
to chase down a breaker? Fuses are much faster and of
course keep the I squared T to less than half cycle. This
may get your catagory classification smaller.
Selective coordination may be a reason for the breakers to be slower at...
Jensen, The best I can do is ANSI 37.17 which part of it sets calibration points for these breakers. NEC may say
1 sec, but the manufacturer who uses ANSI or IEC may have to
use their standards to pass qualification tests. Like many
here I don't have the financial means to be able have these...
Jensen,
From memory there seems to be a UL or ANSI requirement of
a 3 cycle limit. That plus the actual quenching of the arc
could be the total 1 second limit?
bozzah,
the 600 volt motor will let you have more options. Your
VFD choices are more plentifull where the 4160v you have limited vendors and in replacing the higher voltage may
require a longer down time. The safety of the technicians
working on the higher voltage is more of an issue.
the 600...
Electrician1, Sola/Hevi-Duty has a product,a Constant
Voltage Power Conditioner. It is a do-all product that
may take care of your problem. The UPS only helps with
voltage sags, brown outs and power outages. CVPC's takes
care of everything else, but a faulty ground will still
bug you! Make sure...
Electrician1, DPC's skeptism of the harmonics burning
of the mother board seems right. I would question if
the DC supply is the old style 6 pulse or newer 12 pulse.
The 6 pulse was terrible at producing 5,7 harmonics and at
large magnitudes. The newer 12 pulse reduces these to a
more managable...
Roobarb, I hope I'm not intruding,try this site....
www.arcadvisor.com and the site www.csemag.com. The cse
site has a series called "The Art of Protecting Electrical
Systems" it is a 31 issue? series. anyway they are on Part
#13 at their site which is downloadable.I hope I have helped.
The neutral would be switched if there is considerable
amount of Triplen Harmonics. This would be a result from
a Delta-Wye transformer connection. The triplens are not
cansuled in the neutral as other currents,but they add
as much as 1.73 X phase current. Single phase computer
systems are well...