Friends:
This guying is hoping solar will fail. People like this will never be convinced
so I don't try
William
Miller Solar
> On Mar 27, 2014, at 7:07 AM, Allan Sindelar
> wrote:
>
> Wrenches,
> Here's one of the oddest questions I have come across in years:
> PRC Commisioner Lyons issued
First look at what his actual pumping needs are, and come up with a more
efficient way to provide the water.
I just got back tonight from changing out hydronic circulators for a
customer with new Hi Efficiency brushless ECM models. I was able to cut
the watt draw by 65%.
Also, its very possible
Actually the arc is normal, It just depends on where in the waveform is when
the DR switches between Inverter to Generator and how dark the room...
If the Relay is failing direct power, Inverter sales and Service in Tenn, and
Phantom Power Services (Craig Wilburn) should have spare parts.
Anot
Benn,
I recently addressed a similar issue on this list in regard to an
old SW4024 that showed a visible arc when the generator was
disconnected, and the general response was that the arcing didn't
represent a failure, that it was fairly routine.
Ask
Hi Benn,
Over the years I have seen several of the DR inverters burn up near the
transfer switch, or perhaps the switch. I've never dug into the chars to
determine what actually failed. I would replace that relic before the
inevitable happens.
Larry Crutcher
Starlight Solar Power Systems
Wrenches,
An off-gridded (system installed by others) called me yesterday with a concern.
His system is older and has had mods added over the years. It is up to 7x
Siemens SP75 and 1x She'll SQ80P.
I believe the inverter is the original. It is a Trace DR2412, and where the
concern stems from
The Available short-circuit current (SCA) of utility transformer is in the
range of 100,000+ Amps. I still don't see a single phase solar
installation being a large part of that so I doubt that is the issue.
I (partially) understand the issue of reverse current detection in
paralleled utility feed
The "explanation" you quote doesn't make any sense to me. If the
engineer is concerned about fault current, the primary source is going
to be through the utility transformer, and it will be on the order of
5,000 - 10,000A depending on the transformer's impedance. The fault
current contribution
Karl,
I'm taking a guess here but are you doing a supply side connection? What
is the ratings of the devices in the main disconnect grouping?
Best,
-N
On Thu, Mar 27, 2014 at 3:28 PM, Karl Jaeger wrote:
> Nathan,
>
> The only explanation the electrical distributor provided is seen below.
> T
Nathan,
The only explanation the electrical distributor provided is seen below. They
are really skirting a thorough explanation...
The distributor engineer does not view the inverters as a negative load, and
states they will exceed the 500A fault current limit the site is designed for.
Thanks,
Ka
Also in 2014 we get 705.12(D)(2)(3)(c) which should be very useful in
distribution panelboards.
-N
On Thu, Mar 27, 2014 at 3:00 PM, Brian Mehalic wrote:
> The "120% rule" in 2014 is 705.12(D)(2)(3)(b). Ugh. Anyway, the inverter
> current is "125 percent of the inverter(s) output circuit curre
Karl,
Can you give us some more details on their concerns? I've done some very
large single phase ag installs and the only time I've had issues is when we
exceed the 80% of minimum load on the medium voltage feeder.
Best,
-N
On Thu, Mar 27, 2014 at 2:51 PM, Karl Jaeger wrote:
> Dave,
>
> We
The "120% rule" in 2014 is 705.12(D)(2)(3)(b). Ugh. Anyway, the inverter
current is "125 percent of the inverter(s) output circuit current", aka the
minimum OCPD and conductor ampacity value per 705.60(B) and 690.8(B)(1).
This is actually a bit of wiggle room: in 2011 the 120% rule was based on
Dave,
We are about as rural as we can get here farm land. Very good document,
nonetheless.
Karl
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Dave Click
Sent: Thursday, March 27, 2014 1:29 PM
To: re-wrenches@lists.re-wrenches.
I had a nice response all typed up before rediscovering my original
source. Simple answer: there's still a thermal load to deal with even
though there's no point on the bus seeing a current above the busbar
rating. I am a linking machine today:
http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/
I am wondering about the busbar 120% rule, and if there is any wiggle room in
the 2014 NEC.
Fundamentally I don't understand the 120% rule. If my solar breaker is
installed properly at the bottom of the busbar, and the grid-tie breaker is
installed at the top, and the busbar itself is rated for
Karl, you're interconnecting into a spot/area network, right? It's a
real concern; some solutions and background on the issue here:
http://www.nrel.gov/docs/fy09osti/45061.pdf
DKC
On 2014/3/27, 14:05, Karl Jaeger wrote:
Esteemed Wrenches,
We've recently run into an issue with a local distrib
Before I spent any money, I would hire a PE with solar experience to give
you an option. I doubt solar iinverters, which are current limited, would
be a fault current issue. Usually fault current rating is a factor of the
internal resistance of the secondary winding of a high voltage transformer.
S
Esteemed Wrenches,
We've recently run into an issue with a local distributor citing network fault
current on a split-phase service as a reason to prevent interconnection of our
customer's solar array. They've given us the options of reducing our system
size from 36.5kW-DC to 15kW-DC, or having t
Inverter drives make sense for motors almost any size, especially in this
context. I'm certainly no expert but:
1) In the 5-20 hp range, I've seen plenty of single-->3 phase drive options.
These essentially eliminate the startup power surge problem, especially in well
applications. If 1 phase ut
I wonder if it is one of those huge sprayers that they are using in the field
that roll across the field spraying the crops?
They use a massive amount of water on each of their sweeps and I would have to
say that with my limited water pumping experience I would run screaming from
the room!
Ove
Allan,
Chris is on the right track here. Instead of just accepting that they need one
huge pump, what you have to do is determine what they are actually trying to
accomplish. You will need to know what the total pumping head is and how many
gallons per day they need to pump. You will also need
What other technology is asked to do universal service? You wouldn't drive a
dump truck on a family vacation, nor a compact to haul dirt. You can shape
the question for any technology to perform unreasonable service. It doesn't
invalidate the cost-effectiveness of PV for substantial portion of the
Jerry,
Your request is entirely reasonable, and my answer is no, I can't.
The request in my original message came from an online contact
request from someone who was at yesterday's PRC hearing and heard
Commissioner Lyons' comment. I have no further information, a
Very good suggestion, Chris. There was (~2003) an electronic soft start
mostly designed for Franklin motors used in PV pumping applications. Surely
they've become more sophisticated in the mean time. At the time it was
Golden Photon who was working on them.
Bill Dorsett
Manhattan, KS
From:
can you give us more details, are you proposing pumping from a pond, a
well, storage tank what.
Jerry
On Thu, Mar 27, 2014 at 7:19 AM, Chris Mason
wrote:
> I have a couple of suggestions. A pump motor of that size is likely Class
> H and requires a 7x starting current or Locked Rotor Amperage. D
I have a couple of suggestions. A pump motor of that size is likely Class H
and requires a 7x starting current or Locked Rotor Amperage. During
starting the power factor can drop to .2 or lower and the inrush can run to
20 times the rated run current. Even diesel generators have a very
difficult ti
Wrenches,
Here's one of the oddest questions I have come across in years:
PRC Commisioner Lyons issued a challenge to NM solar
companies today.
He stated that he cannot get his electric coop to bring three
phase into his property to run his irrigation (a 150 hp
Hi William,
I should have clarified that I was speaking about commercial system with
the Sunny Tripower or Power-One Trio type 1000 V string inverters. Many
commercial roofs have stairwell access which makes getting the inverters
up and then later servicing them relatively easy. But, yes, we have
HI Chris,
According to the spec sheet, the Sunny Tripower is rated MPPT from 300 V to
800 V with a min MPPT tracking capability down to 150 V. It seems like
going below 600 V would work fine witch that particular inverter. I haven't
checked the specs on all the others.
Best, August
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