>
>
> Hi Jay,
A 75kVA low voltage transformer will have roughly 0.3% iron core losses and
have an efficiency loss of roughly 2%. It depends on when the transformer
was made and what efficiency standard it was adhered to. the manufacturer
should be able to provide you with the testing results
William,
I've used a lot of services from Fat Spaniel, SolarMagic, Draker, Noveda,
AlsoEnergy, Locus, Qantum, Powerfactors, and Green Power Monitoring. Which
one is the best is highly dependent upon your preferences and what services
you require. I prefer AlsoEnergy for numerous reasons, one
that. It is,
however, less than the traditional BSTC nameplate x 1.25 method.
Regards
Steven Lawrence, PE
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Hi Adam,
I have a 3.3MW site using Hanwha 400s where IV curve tracing and other
voltage checks found roughly 1% of the modules are experiencing some type
of voltage issues. We all suspect bad diodes. We just got the site up and
running and we will be doing an aerial thermal imaging flyover to
I design a lot of grid tied projects, but I still do a rooftop about once
or twice a year. All of them going back 7 years or so always used
covered/vented cable tray. This includes homeruns, DC feeders, and all AC
wiring. There still is some metallic conduit used (usually EMT) - a small
jumper
We've averaged maybe 1 or 2 on 6MW projects over a year with
this hard requirement versus 100+ we had on a 1MW rooftop project that
mixed multiple manufacturers.
Steven Lawrence
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Phoenix contact makes a bunch of wireless radios and relays that can
communicate discrete signals as well as standard communications. I've used
it for a minimum export relay with SCE and telemetry for SCE. It's simple
to install and use. If you're going wireless, make sure you have line of
Hi James,
Is the solectria combiner actually combining strings so you have one input
into the SMA inverter? If so, did SMA approve arc fault detection at that
high current? From what I understand, arc fault detection doesn't work on
strings greater than 20A.
In the solectria box, I'm assuming
) of modules to store to ride out the
tariff.
I imagine utility scale projects will be hit the hardest. When you have a
$0.10/W tariff being added to a $1.00/W project, that's a 10% increase,
which means a lot of projects won't go forward.
-Steven Lawrence
Hi Ray,
Have you checked the torquing on all the other bolts? My company's had a
few projects where some modules blew off - it's always been due to
over-torquing of the bolts.
Steven Lawrence
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Just to expand on this, the NRTL has to test to the specific UL standard.
However, if you look at the definition of "listed" in the NEC, it states
"equipment, materials, or services included in a list published by an
organization that is acceptable to the AHJ...). I have heard of some
Kirk,
Double check those connectors very closely. On our other projects,
Canadian solar doesn't use MC4 connectors - they use PV2 which we found
does not mate well with MC4.
Steven Lawrence
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I've had no issues traveling with a DMM and its associated probes.
However, I did travel one time with the Seaward analyzer and that set off
the bomb detection machine. Not a very fun 30 minutes.
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Hi Dan,
I don't know which state you're in, but the state of NJ put out a notice
stating that solar panels do not require servicing. This came from the top
electrical inspector back in 2010. The link can be found at
Hi Bill,
For a Solaron, I've used a plastic stair tread, some velcro and some super
glue to cover the display. Only a few bucks from Home Depot. It's worked
out pretty well provided it's not very windy.
Steven Lawrence
Date: Thu, 2 Oct 2014 07:45:01 -0700
From: frenergy frene...@psln.com
. The SMA CP-US inverters are transformless
and can use a solidly grounded conductor.
-Steven Lawrence
Hello Wrenches,
Attached is an article from Home Power that came in my email. It says
module degradation is increased by PID (Potential Induced
Degradation) by the use of transformerless
Hi Max,
Try http://epsii.com/users/awp.php?ln=121219
I just used them for some relay testing and they were outstanding.
Thanks
Steven Lawrence
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) with the full mask on, especially when it's hot outside, but it is
something everyone should be doing when troubleshooting anything energized.
Stay safe.
Steven Lawrence
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Hi Marco,
It goes back to 690.35(D). Transformerless inverters are usually
ungrounded PV systems, so the wire must bein raceways, or it must be PV
wire.
There are a few exceptions, the SMA CP-US inverters can have a grounded
conductor, but you must have a floating AC neutral.
And the Solarons
Esteemed wrenches,
Does anyone know of an IV Curve Tracer that's rated for 1000VDC and 30A? I
can find some 1000V tracers but they're only at 10A.
Thanks
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Dana,
Maybe wire 3 in series to a single Enphase? It'll depend on what the
voltages are.
Date: Tue, 4 Jun 2013 14:01:42 -0600
From: Dana d...@solarwork.com
To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org
Subject: [RE-wrenches] Old Modules for GIT system?
Message-ID:
Luke,
Most tankless hot water heaters can't accept pre-heated water. Some of
them can, but even still these have a minimum heat input into the water.
You may run into a situation where you have 105F water into the tankless
and the thing won't fire up due to safety reasons (can't put out 130F or
Hi Robert,
Get a mega Ohm meter, isolate the home runs and perform a test. You should
get 550 MOhms. If not, there's something likely wrong with that string
that's causing the intermittent ground fault. Or, have someone stand on
the ground with a hose pointing it at the roof and try to find it
Hi Conrad,
Without any specs on what the redundant relay is trying to accomplish, I'm
guessing you'll need the SEL 547. It's a microprocessor relay that takes
voltage and current and will trip a circuit breaker provided you have a set
of PTs and CTs.
Steven Lawrence
Date: Tue, 20 Nov 2012
Allen,
I use to use them on the old Sanyo modules. As long as the combined short
circuit rating is less than the series fuse rating, you'll be ok. They're
really only good for modules with high voltage/low current.
-Steven
From: Allen Frishman amfr...@aeonsolar.com
To: RE-wrenches
Hi Marco,
Check out Bentek, Shoals, and SolarBOS. If you're doing thin film, I
suggest looking into the in-line fusing from Shoals.
-Steven
Date: Mon, 6 Jun 2011 13:04:35 -1000
From: Marco Mangelsdorf ma...@pvthawaii.com
To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org
Subject:
It's the same thing here. They aren't taking any large orders from us.
Steven Lawrence
NABCEP Certified Solar PV Installer(tm)
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Date: Mon, 17 May 2010 18:22:27 -0700
From: i2p i...@aol.com
To: List for complaining about anything RE.
re-bitch...@lists.re
service panel that
can be fed from the backup load panel.
Steven Lawrence
__
Date: Wed, 31 Mar 2010 08:13:10 -0700 (PDT)
From: Nick Soleil nicksoleilso...@yahoo.com
To: RE-wrenches re-wrenches@lists.re-wrenches.org
Subject: Re: [RE-wrenches
loads aren't over 60A,
and what's left in the main service panel wouldn't be over 60A. But yeah, it
always depends on the AHJ.
Here in NJ I try to stay away from panel upgrades whenever possible. They can
run from $2k-$3k, and that's not an adder I want to put on a client.
Steven Lawrence
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