This seems more convenient than remembering the constants for copper and
aluminum. Please note that I did not give the complete units for those in my
previous email. The units for ³k² in those formulas is ohms/mil foot.
On 12/8/08 6:48 PM, "Michael Gullo" <[EMAIL PROTECTED]> wrote:
> Marco,
>
Marco,
I use the following formulas:
single-phase Vd = (I x L x R x 2)/1000
3-phaseVd = (1.73 x I x L x R)/1000
L = one-way length
R = resistance of conductor from Table 8 (usually from uncoated copper ohm/kFT
column)
Mike
Michael Gullo
Solar Solutions LLC
Marlton, NJ
NABCEP
Marco,
The formulas I learned in school are:
Single-Phase Vd = (2 * d * k * I) / cm
where: d = distance; the constant k = 12.9 Ohms for Cu & 21.2 Ohms for AL; I
= current; cm = circular mils
3-Phase Vd = (1.73 * d * k * I) / cm
My note are failing me, but I believe d is actually the one-way di
Hello Jason,
The correct voltage-drop calculation requires round-trip distance. Two
conductors, each the same gauge and carrying the same current will have equal
voltage drop.
For example:
Conductor # 1
---
Depends on what table or calculations you are using.
The current has to flow the full distance, out and back, but most tables I have
seen have that figured into it. If you are using the resistance from something
like AWG wire tables, then you need to use the round trip distance.
...
Hi all,
Until recently, we've only been required to have an electrical permit for
flush-mounted PV systems. The city has now decided to require building
permits for all PV systems and wants to come out and inspect our L-feet
attachments and rails before the modules can go up. This seems crazy to m
Marco,
One way it the appropriate answer, you mostly have voltage only going in
that direction is my thought.
On Mon, Dec 8, 2008 at 3:12 PM, Marco <[EMAIL PROTECTED]> wrote:
> I feel kinda foolish in asking this.but when calculating voltage drop
> in a conductor over distance, do I use the
Round trip...
(unless you are using a table that has already counted this in)
Take care,
Walt
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Marco
Sent: Monday, December 08, 2008 2:13 PM
To: re-wrenches@lists.re-wrenches.org
Subject: [RE-wrenches] voltag drop
I feel
I feel kinda foolish in asking this.but when calculating voltage drop in
a conductor over distance, do I use the one-way or round-trip distance?
thanks,
marco
Marco Mangelsdorf, Ph.D., President
Electrical Contractor License C-26351
69 Railroad Avenue, Suite A-7
Hilo, Hawaii 96720 US
Great! I was looking at their Model 70 Spec sheet. I will go back and read
the specs on the Model 70 as well as the Model 500 more carefully.
- Peter
Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
Ph 323-258-8883, Mobile 323-83
All of the pressure reducers I have seen work at no pressure - I think
you are misreading the specification sheet - the zero drop at zero flow
is referring to pressure drop due to flow - not due to the function of
the regulator - its sort of like zero voltage drop at zero amps...
The spec sheet
Hi Peter,
Yes Schneider Electric SA completed their acquisition of Xantrex in
October, we are now a subsidiary. All customer support staff are the
same great group, and I know they have been working with you on your
issue. We will continue to work with you this week to help sort out what
ever p
I can vouch for the Tile Trac as well. After your installers get a couple of
install under their belt, the install goes pretty smoothly. A couple of
things that weren't mentioned. The 3/8" clearance hole accepts a 3/8" SS
"all thread" which can be used to level a waney roof (to a degree), and the
a
I have not used the QMPV system on flat tile, and I wanted to suggest Tile
Trac if you do one again. It is much easier and only a small 3/8" hole to
drill which equates to less leakage problems.
Just my 2w.
On Sun, Dec 7, 2008 at 9:09 PM, Kelly Keilwitz, Whidbey Sun & Wind <
[EMAIL PROTECTED]> wr
Dean,
Thanks for the info on the tankless water heater. However, when I looked up
the specs on the Watts regulator, I found the same behavior: zero pressure
drop at zero flow. So the Watts regulator will not solve the problem of high
water pressure at night (when there is zero or very little fl
One method of installing PV on tile (any type) is to remove the tile
and install a rolled roof material under the array area. Then
reinstall tile up to the edges of the array. The array is lowered and
framed by the tile and allows for simple installation. It looks good
too.
Kindest Regard
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