Outback VFX3648

stooper2 · January 2008

Hello Everyone.

I wanted to post this question on the Outback forum but I've been waiting for my Log in confirmation since yesterday so I'll give it a chance here.

Is it possible to connect 6 of the Outback VFX3648 inverter/chargers together?

Thanks in advance.

Rick

crewzer · January 2008

Re: Outback VFX3648

Rick,

The answer is a qualified "yes". My undestanding is that a Mate and Hub are "must haves" for stacking the OutBacks, so the practical limit is 10 inverters, as a Hub-10 has ten ports. Networking other devices (i.e., a controller(s) and/or FN-DC) via the Hub-10 reduces the number of ports available for inverters.

What are you trying to do: 120 VAC only, or 120/240? For three-phase, the limit is three inverters. For 120/240 VAC 60 Hz grid-interactive applications, the limit is two inverters.

Also, there's a lot of related info in the inverter manuals as well as in the "Documentation" section on OutBack's website.

HTH,
Jim / crewzer

stooper2 · January 2008

Re: Outback VFX3648

Thanks for the reply Jim.

The system will be configured in an off grid 240 volt system. I will need aprox. 1800 watts at peak. From what I have read I will need an "auto" transformer to do this. I'm guessing this is just a step up transformer.

If I were to have the 6 inverters, I understand I would need the hub and mate, could I get away with using only one transformer?

crewzer · January 2008

Re: Outback VFX3648

Rick,

I suspect you meant 18,000 W...

A stack of six VFX3648's with an X-240 auto-transformer in a 120/240 VAC configuration should do a very nice job for your off-grid application. Here's a link to an applicable wiring diagram from OutBack: http://www.outbackpower.com/pdfs_wiring_diagrams/OFFGRID6STACK.pdf

HTH,
Jim / crewzer

stooper2 · January 2008

Re: Outback VFX3648

Again thanks for the reply Jim. And yes, I meant 18000 watts. I guess I had a brain fart there. I have looked at the schematic aswell. Thanks for posting.

With having 6 - 3048 inverters can I still get away with using only one auto transformer?

crewzer · January 2008

Re: Outback VFX3648

Rick,

Yep, just one auto-transformer.

Here's how it works. One inverter is the "Master" on hot leg #1, and the other five would be "slaves". At power levels below ~3,600 W, the master inverter would supply all power, and the other five would "sleep" in a low-power mode. The auto-transformer would distribute the master inverter's 120 VAC output across the two hot legs as required. As power requirement exceeds ~3,600 W, the Master will signal successive slave inverters to turn on and supply additional power.

Here's a link to the OutBack documents page. This'll help keep you busy until your confirmation arrives. See: http://www.outbackpower.com/doclinks.htm

HTH,
Jim / crewzer

Solar Guppy · January 2008

Re: Outback VFX3648

You can do the same thing with 3 Xantrex XW-6048's and don't need any extra "hardware" just a standard cat5 cable to dasiy chain the Xanbus communication line ... it will also be a lower cost installation as the XW's are already 240V units.

stooper2 · January 2008

Re: Outback VFX3648

Thanks for the reply guys. The fellow in question is set on Outback so I guess that's the route I will have to go with. Jum, thanks for the reply. After I'm finished reading that, I'll let you know how everything works out.

I'm sure I will have plenty more questions.

Thanks, Rick

westbranch · January 2008

Re: Outback VFX3648

Hmmm, that is not a lot of amps @ 240 v (75 a by my calc. ?)...
Could I ask what machinery will be powered? My reason is to evaluating the total cost of trying to use a 220 v submersible pump vs 110 v vs DC powered..

thanks
Eric

stooper2 · January 2008

Re: Outback VFX3648

Hello Eric.

The system will be used at a remote airport for landing lights which are controlled by aircraft while on approach.

I had a typo there and wrote 1800 watts when in reality I meant 18000 watts.

Solar Guppy · January 2008

Re: Outback VFX3648

For a FAA air strip you had better use Class B listed equipement, the Outback inverters are NOT class B and might interfer with aircraft communication or navagation

Xantrex XW is class B certified

boB · January 2008

Re: Outback VFX3648

>>For a FAA air strip you had better use Class B listed equipement, the Outback inverters are NOT class B and might interfer with aircraft communication or navagation

FCC Class B limits for conducted radiation stop at 30 MHz. This is in contrast to just "radiated" from the inverter box, which is normally much less of a problem than conducted, which is radiated from the AC output cable. Aircraft frequencies are about 120 MHz. The majority of FX conducted RFI is less than 30 MHz and much less at 120 MHz. If you DO have trouble, a simple common mode filter on the 120VAC output would help greatly, for whatever inverter you use.

And remember, FCC class B is great, but doesn't mean NO RFI is generated. Sometimes, more importantly is what frequency is radiated. If just right, it will interfere. If not on the same frequency, it won't interfere. Certainly the lower amount, the better.

Henry, if you have a graph of the FX/VFX, I'd love to see it. I know that the X tested it at one point. I think that OB has done some work to it since though.

boB
K7IQ

mike95490 · January 2008

Re: Outback VFX3648

Not so much FCC type, but are there reliability issues that the FAA is interested in, or is this a private landing strip ?

crewzer · January 2008

Re: Outback VFX3648

My three cents (inflation, you know...) is that it might be worth some objective reasearch into what the applicable FAA requirements really are. FCC Part 15 Class B is primarily intended for residential applications, and it may or may not be applicable to the the FAA's range of concern/authority.

HTH,
Jim / crewzer

niel · January 2008

Re: Outback VFX3648

as to the unwanted radiation from a controller or inverter, any controller/inverter is capable of interfering. being certified means it won't exceed a certain level of interference, but as was brought up it is not a guarantee of not being interfered with. i know we aren't talking controllers, but it applies to them too so i mention both here. many computers are in this class and i see rf spikes from my pc in many places of the spectrum, though they are small they are there. to my knowledge the faa hasn't put restrictions on computers/inverters/controllers, but don't quote me. the faa is more strict while on large commercial planes, but i can't say if it extends to the ground operations or not or to what extent it might.
my opinion is for you to get whatever you think will suffice for you, but make sure you can return it towards another or be able to be refunded your investment if it doesn't perform as you wish. do carefully scrutinize whatever you get by verifying under both full load and no load circumstances that you will not see interference and the opinion of the faa couldn't hurt as it is they that make the rules for flight. interference can also be cured in many cases if you'd wish to try that route, but it will take a bit of knowledge many lay persons don't have. they probably haven't had a reason or call to rule on the uses of such equipment as it generally is not encountered in the field of aviation as generators are a given 99.99% of the time.

mike95490 · January 2008

Re: Outback VFX3648

If this is going to be used for runway lighting, the "type" of bulbs used, may become a factor, as tungsten bulbs have a high surge for the first few cycles. 18KW [150A @ 120V] of tungsten may have an un-acceptable surge. Also the dimmer and control circuits may need to have some "logic" applied to them, to allow inverters time to "catch up" to the load that gets thrown at them.

Switching a runway ON from utility power may be a different animal from the inverters.

It might even be easier to switch the Inverters On and Off, rather than the loads. I don't even want to think about the battery bank this beast will require.

stooper2 · January 2008

Re: Outback VFX3648

The battery bank is HUGE.

Hello all - interesting read going on here.

The airport in question is in a remote community. The runway is very short and only handles smaller aircraft (King air, Metros, Pipers etc).
The runway lights are controlled by the approaching aircraft.

As for the surge of the lights, the system specs were put together by to electrical engineers so I have to assume they know what they're doing.

From what I have been told, the draw on the lights themselves are well under 8000 watts at start up. They wanted the 18000 watt system because they want to power the airport (gas furnace, stove etc) only if the back up generator won't start.

The system is WAY oversized for what they actually need.

niel · January 2008

Re: Outback VFX3648

i have to add that you should inquire as to the nature of the bulbs used (inandescent, flourescent, or led) for they do make led arrays for towers and such and i don't see why it couldn't work for runways. this would reduce the loads quite a bit. it has been awhile since we've discussed this sort of thing, but give it a search here and even on the net.

stooper2 · January 2008

Re: Outback VFX3648

The bulbs being used on the runway are incandescent. There is no tower at this facility either. As mentioned, it is in a remote area and landings and take offs are controller at another airport some distance away.

Outback VFX3648

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