Bill,
Not a lot of personal experience with this issue. The one time I had to deal
with it, we were able to leave the circuit on, once we got it energized.
As you know, the crux of the problem is the nature of the voltage relative to
it's cycle when connection is attempted.
An internet search
Sorry for the additional post here, but it includes a typo correction:
Bill,
Not a lot of personal experience with this issue. The one time I had to deal
with it, we were able to leave the circuit on, once we got it energized.
As you know, the crux of the problem is the nature of the voltage
Before I present a suggestion, here's a question:
If by chance William is able to energize the transformer without tripping
the breakers, what if there is a brief break in the power...such as a
half-second?
I don't suppose there's capacitance here...more like magnetic flux...but
would there be a
Interesting question, Mick. It may depend on the point in the cycle when the
transformer lost power and the duration of the blip.
Dick Ratico
--- You wrote:
Before I present a suggestion, here's a question:
If by chance William is able to energize the transformer without tripping
the breakers,
You should also take a look at the slick app for a iPhone or iPod Touch (if you
don't need or want the phone), it is called SunTracker and was recently
purchased by Solmetric (if you can't beat 'em buy 'em!). Also the Sun Seeker
app is very nice and also gives you shadow path ratio and length
Richard L Ratico wrote:
Interesting question, Mick. It may depend on the point in the cycle when the
transformer lost power and the duration of the blip.
Dick Ratico
--- You wrote:
Before I present a suggestion, here's a question:
If by chance William is able to energize the transformer
We went over this stuff in class last year.. I'm hoping some if it stuck... seems to me you're on table 450.3(B) of the NEC.. if you choose to protect the primary only, you're restricted to 125% of primary FLA. IF you choose to protect both primary and secondary, you can size to 250% of the
Friend:
Thanks for the responses. They have all been valid on offered good
options. There is one possible solution that will be easier to implement
and is worth a brief description here:
Breakers have an AIC (Ampere Interrupting Capacity). This is a
quantification of how much fault
Marco,
Seems to me he's right. It carries the net current difference between
L1 and L2 from the transformer to the loads.
But not having any EE training, I'm willing to learn better.
Allan
Allan is correct.
In a 240V 3-wire system (L-N-L), neutral carries no current with 240V loads.
In a *perfectly balanced* 120V system with absolutely equal loads on both L1
and L2, neutral again carries no current. Key here .. absolutely equal loads.
Given unequal loads (the norm), the
Do those apps have location specific info that will translate percentage sky
blockage into percent annual solar energy so it can be used for PV
calculations?
Dana
Dana Brandt
Ecotech Energy Systems, LLC
www.ecotechenergy.com
d...@ecotechenergy.com
360.510.0433
On Thu, May 13, 2010 at 10:40 AM,
Marco,
When you are drawing 120 VAC, the neutral is a current carrying conductor.
David
David Katz
Chief Technical Officer
AEE Solar
1155 Redway Drive
P.O. Box 339
Redway, CA 95560
Tel (707) 825-1200
Fax (707) 825-1202
dk...@aeesolar.com mailto:da...@aeesolar.com
www.aeesolar.com
Marco:
You have opened a can of worms. I hope you are happy!
Are you looking for the legal definition or to discover if the neutral
conductor actually carries current? The answer to the legal definition is
in 310.15(B)4 (2002), and the answer is: It depends (on the type of
service). This
Fellow Wrenches,
Some time ago, Windy Dankoff had a rule of thumb to substitute (conservatively)
an AC breaker for use in a DC application.
Is anybody's memory, or perhaps even the old dog himself; if he is listening,
better than mine?
TIA,
Bill Loesch
Solar 1 - Saint Louis Solar
314 631
Bill:
I thought the rule of thumb was: Don't do it.
William Miller
At 05:10 PM 5/13/2010, you wrote:
Fellow Wrenches,
Some time ago, Windy Dankoff had a rule of thumb to substitute
(conservatively) an AC breaker for use in a DC application.
Is anybody's memory, or perhaps even the old
I thought the Sq.D QO for sizes up to 60 amp was rated for DC? and only the
Square D
Also why not use DC breakers? Robin makes some very small breaker boxes, and he
alos has high voltage breakers, (at least 250 volt? DC)
Darryl
--- On Thu, 5/13/10, William Miller will...@millersolar.com
Is this conversation what you were refering to? 7/22/01
Others offered caution to this approach, but clearly the subject was
switches, not breakers.
Allan at Positive Energy wrote:
2. ...
I am using float switches to control 48V mercury displacement relays
for these DC pumps. Can anyone suggest
Wow, Michael, look at the monster you have created, Dr.
Frankensolarbozo!
Yes, that's the thread. And I was about to post that Windy left today
for Costa Rica...just a trip, not a move.
William, there are certain perfectly appropriate applications - such as
a pressure switch controlling a DC
Thanks for sending that link, William.
OK.let's try it from a different perspective.
When you're running, say, three three-phase hot conductors from point A to
point B with a neutral conductor, should that neutral be considered current
carrying from the perspective of more than three
Marco,
Take a look at 2008 NEC 310.15(4)(a). The neutral conductor isn't
counted for the purpose of NEC 310.15(B)(2)(a) when it is part of a
circuit where it only carries the unbalanced current.
Kent Osterberg
Blue Mountain Solar
Marco Mangelsdorf wrote:
Thanks
for
Marco:
Will non-linear loads be expected? If so, the neutral is considered to be
a current carrying conductor and needs to be counted. If no non-linear
loads, then the neutral is not counted.
Code citation below (2008):
310.15(4) Neutral Conductor.
(c) On a 4-wire, 3-phase wye circuit
How about some clear definitions-for-dummies of 1) linear loads and 2)
non-linear loads?
marco
Marco:
Will non-linear loads be expected? If so, the neutral is considered to be a
current carrying conductor and needs to be counted. If no non-linear loads,
then the neutral is not counted.
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