240 Vac generator

Discussion about the FX2000 Inverter
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RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

Hello everyone.

I've been running at 120VDC (using Exeltech inverters, homemade solar and hydro charge controllers) for the last 25 years and am contemplating going to 24VDC with a couple FX2024's. My question is: can I parallel the inverters to provide 120VAC but still feed them off both legs of my 120/240 VAC/5KW generator? Or will I need a transformer ahead of the inverters to avoid nasty neutral currents and sync problems?
I want to use the 240 wiring because it will keep a more balanced load on my generator windings.

I've gone through the documention and this site but i have not found an explicit reference to this option. I know I can go 120/240 out of the series-connected inverters with the X240 but would rather avoid the losses incurred with using transformers.

Cheers

Rob
wd8cdh
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Posts: 131
Joined: Tue Jul 23, 2002 11:01 pm
Location: Long Island NY

240 Vac generator

Post by wd8cdh »

Hi Rob,

You will need a transformer for a 120V parallel system. Why don't you want to go with a 120/240V system? You don't have to have a transformer for a series connection.

<small>[ October 25, 2003, 06:46 AM: Message edited by: Ron Schroeder ]</small>
RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

Thanks for getting back to me Ron. I only have 120V to the house at the moment and was hoping to avoid laying another 300 feet of copper to get 120/240. I want to be sure to examine all aternatives to transformers permamently using up power 24 by 7. Can I disconnect the X240 breaker at the panel and reconnect when i need the load balancing feature?

Rob
wd8cdh
Forum Guru
Posts: 131
Joined: Tue Jul 23, 2002 11:01 pm
Location: Long Island NY

240 Vac generator

Post by wd8cdh »

Hi Rob,

Yes, you can have the transformer on the generator side of the breaker.

Ron
RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

Yes, that makes sense. Will cost out another roll of #3 in case I do decide to add the second leg to the house.

Thanks for your time.

Rob
Robin Gudgel

240 Vac generator

Post by Robin Gudgel »

Since you are planning on adding 240 later, here is a solution. Add an X-240 out at the generator to step down the 240 to 120. You will need to protect the transformer from the elements. It will draw power only when the generator is running (10 watts). When you add 2 FX inverters you should add the additional wire so you will have 240 to the house and to the inverter system. At that time you will move the x-240 to your half rack system (PS2). The X-240 will then be balancing the inverter loads. Normal operation works like this: One inverter on or in search (leg1 master), X-240 on or in search, 2nd inverter asleep (leg2 slave). The X-240 is at this point supplying 240 from the leg1 master inverter. This is how it will work up until about 1000 watts of output. At that time the master tells the slave to wake up and help power the loads. We will assume a 5000 watt load was turned on. If the big load was a 240 volt load, the X-240 just sits there doing nothing. If it was a 120V load on leg 2, the X-240 will take power from the leg 1 inverter and run in parallel with leg 2 and vice versa. Once the load diminishes, the leg2 inverter goes back to sleep. In otherwords, the X-240 allows series and parallel operation at the same time. The leg2 inverter draws 2.6 watts asleep. They wake up and help out the master in less than 16 milliseconds too. Very fast! You can have up to 10 inverters hooked up like this. Idle power is still one inverter, one X-240 and 2.6W for each slave. Slaves can be on both leg1 and leg2.
RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

Wow, Thank you for the detailed reply Robin. That basically covers all my issues. Outback should add your analysis to their FAQ database as I'm sure not to be the only person curious about the power losses in such a complicated and interactive system. Although I will be getting way more power and flexibility I am going to have to do a bit of energy budgeting for the second inverter and transformer, small as those loads may be. I am more than 15 Km (of water)from the nearest grid connection so every watt counts. I am also going to look at putting a big P&B DPDT relay on the X240 since I won't be needing the full parallel output of the system unless I am working in my shop. Some loads are substantial but mostly 120 (rectified 120VDC motors).

Cheers,

Rob
RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

Robin and Ron, As a short addendum for any other people reading this thread I just want to confirm that the idle power consumption of the two-inverter & X240 configuration is approx. 15 + 10 +2.6 = 27.6 watts (0.6Kwh/day) with one inverter always on - and less than half that assuming the primary inverter can also go to search despite having the X240 as a phantom load...
Robin Gudgel

240 Vac generator

Post by Robin Gudgel »

Rob,You got it. The master inverter as well as the X-240 can go to search mode. We have made improvements to our code within the last few months that improves search mode with an X-240 also. I can't remember the exact power draw in search mode with an X-240, but I remember being impressed. I will try to get it tested and documented in the future.
RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

Thank you Robin.

Firm numbers and optimized firmware will be very useful to lots of energy-strapped users. That takes care of the inverter design part of my project for the moment. Now on to determine how best to rearrange my solar array from two parallel strings of 115VDC (at load) to a lower voltage/higher current. Not sure MPPT will be the way to go given that it never gets that hot here. On the other hand I hate the thought running all that additional wire through the bush!

Anyway I'll save all that for your MX forum if I get really stuck...

Regards,

Rob
arnold
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Posts: 158
Joined: Sun Jul 07, 2002 11:01 pm
My RE system: Current: 10.9 kW STC (128 BP-585), 4 MX60, 3 GVFX, 4 Concorde PVX-12255
2.46 kW STC (12 KD205GX-LP), Xantrex GT2.8
Previous (still owned): 9.1 kW STC (108 BP-585), 6 SB 3048, 2 SW5048, 8 Concorde PVX-12255

240 Vac generator

Post by arnold »

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Rob Linschoten:
<strong>Thank you Robin.

[snip]
Not sure MPPT will be the way to go given that it never gets that hot here. On the other hand I hate the thought running all that additional wire through the bush!
[snip]

Rob</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">[img]images/smiles/icon_confused.gif[/img] If it never gets hot there then MPPT helps more.

arnold
RobL
Forum Guru
Posts: 319
Joined: Thu Oct 23, 2003 11:01 pm
My RE system: (1) VFX3524, (3) FM60, 4KW PV, Kubota 6.5KW, Honda EU2000, Hub with Mate2, Surrette S430 and S1380 banks wired for 24V. This is my third system. started with a Dunlite 2KW Windcharger into 120V bank of 8D's into Honeywell rotary inverters in 1978.
Location: Vancouver, BC

240 Vac generator

Post by RobL »

My bad. We actually have only two seasons here on the coast and no spring or autumn to speak of. Temperatures generally range between 0 C and 28 C depending on which of the two seasons we're in.
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