"Terry Coombs" wrote in message
news
On 5/26/2018 3:43 PM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
news
On 5/26/2018 2:12 PM, Jim Wilkins wrote:
"Terry Coombs" wrote in message
news
On 5/26/2018 11:53 AM, wrote:
On Sat, 26 May 2018 05:41:56 -0000 (UTC), James Waldby
wrote:
On Fri, 25 May 2018 17:38:09 -0700, etpm wrote:
On Fri, 25 May 2018 08:40:22 -0700 (PDT), "Dave, I can't do
that"
wrote:
I have a 1-1/2HP, 220v motor running from the dryer socket,
all
good.
...
The house wiring uses the 3-wire 110-0-110 for the 220/240
but
the gen
has three pins for the 240-out. I am guessing one is Ground
and
the
others are Neutral and 240v.
...
The reason neutral wires are called that is because they are
tied
to
ground in the breaker panel which means there is no potential
voltage
between the neutral wire and the ground wire, at least in the
breaker
panel. So there is no neutral on the generator unless [...]
"The reason neutral wires are called that is because they are
tied
to
ground" seems to me to be incorrect. True, in US wiring,
neutral
wires
usually have near-ground voltages on them, but more generally
a
neutral
wire is one with no current flowing in it when a system is in
balance.
In US wiring the neutral CAN have current running through
it.
Eric
In a properly balanced load center that current will be
minimized
... so I corrected your statement .
--
Snag
The neutral carries the difference between the hot leg currents.
If
the load current is 100A on one leg and 0A on the other the
neutral
will carry 100A. Increasing the load on the other leg decreases
the
current in the neutral, so with 100A through both hot legs the
neutral
carries 0A, not 200A, and it can be the same size cable as the
two
hots.
Conceptually you get the right answer if you treat both loops of
the
circuit as separate and then add the currents, If the neutral has
100A
flowing in from one hot leg and simultaneously 100A out to the
other
they will sum to 0
The relevant circuit analysis principle is that the currents into
and
out of a wire junction have to sum to zero, since you can't
create
or
destroy electrons. A capacitor at the junction doesn't negate
this
rule, it turns the solution into a problem in differential
calculus
whose answer is an equation of voltage versus time.
The Romans used the same net-sum principle to run an empire-wide
checking system. When a merchant wrote a check for a cargo of
wheat
in
Egypt the amount was simply deducted from tax payments sent back
to
Rome, and when he returned home the merchant had to reimburse the
treasury (or become lion poop). Thus only the heavily guarded tax
shipments were at risk from storms or pirates.
-jsw
Jim , I was an electrician when I was in the Navy ... and as I
said
, in a properly balanced load center neutral current will vary ,
but
the idea is to minimize it .
--
Snag
The ship designers can predict and apportion the loads, which may
not
be practical for residential, commercial or industrial
installations
subject to unexpected, unengineered and perhaps undocumented
changes.
Plus warships are necessarily relatively symmetrical and redundant
and
lack the enormous motor startup surge capacity of the grid. The
analysis I gave works for all situations, not just your
well-designed
and controlled ones.
I've traced and numbered my home outlets so I know which side, odd
or
even, they are all on. But I have to plug the portable air
compressor
and MIG, microwave, window air conditioners and heat treating oven
into whichever hot leg's outlet is nearby. The 120V heating and
cooling loads will never be balanced because they cycle randomly. I
have a 200A electric heat service so balancing 20A loads doesn't
matter, and the big compressor, TIG and plasma cutter are 240V
anyway.
What can you tell of the South Dakota incident?
https://www.tapatalk.com/groups/wars...al-t24931.html
http://www.kbismarck.org/forum/viewtopic.php?t=1734
http://www.dcfp.navy.mil/mc/museum/War_Damage/57.pdf
"That won't help you very much. The report was whitewashed to cover
up
what had happened. You may look in vain for any reference to the
sabotage."
-jsw
Well Jim , all I can say is that I'm doing the wiring in my house ,
and I'm trying to apportion loads to minimize neutral leg current .
Just seems like the right way to do it - though I can see why a pro
wiring a new house probably just sticks 'em wherever with no regard
to balancing loads .
--
Snag
Ain't no dollar sign on
peace of mind - Zac Brown
I think balancing the loads is a good idea too, but I wouldn't let it
override other standards.
https://www.thespruce.com/common-ele...y-room-1152276