navitron
 
Renewable Energy and Sustainability Forum
UK's most popular Renewable Energy Forum July 23, 2014, 12:22:02 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address - following recent spam/hack attempts on the forum, all security is set to "high", and "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Installers of the Month - 2014 | Spreading Solar to Schools Across the UK | Farmers Encouraged to Harvest Solar Energy to Save Money
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: connecting ac generator to grid tie inverter  (Read 3532 times)
michiel
Full Member
***
Offline Offline

Posts: 181


Gaia


« on: March 01, 2011, 09:21:43 PM »

Hi,

I have a Lister cs powered 5Kw 1ph AC generator, and want to grid connect this.
I am looking at Fronius IG inverter.

Do I really have to rectifie the AC to DC, and then get the inverter to change it back to AC again, or is there a way of feeding the inverter direct with AC??

Probably a stupid question, but assume I will loose % efficiency every time I rectify??

 
Logged

11kW Gaia-wind, 3.85kW PV mounted on 3x trackers, Borehole fed 32kW GSHP, 10m^2 Flat plate Solar, 100x58mm (Navitron) ET's, 1000Lt heat store, WVO Lister CS CHP, WVO powered VW Caddy, 4 chickens and 3 ducks, (edit, ducks no more, taken by fox!)
guydewdney
Hero Member
*****
Offline Offline

Posts: 3859



« Reply #1 on: March 01, 2011, 10:03:58 PM »

Nope - you will need to rectify, and probably smooth before the inverter will take it - check the inverter's spec to see what 'ripple' it will take - plain rectified single phase probably will be too wobbly - which is why most people use 3 phase rectified.
Logged

Pic of wheel on day 1
7.2kW Waterwheel and 9.8kW PV
jotec
Hero Member
*****
Offline Offline

Posts: 611



WWW
« Reply #2 on: March 01, 2011, 10:08:14 PM »

I looked at this and found that the inverters I looked at would not like rectified AC from single phase without it being smoothed.
In the end I used a 3 phase wind turbine pma and .a 3 phase rectifier. This gave a ripple well below 10%. Incidentally 5kw is well above the g83 limit.
If it is an encouragement to go for it though I have generated approaching 3MW this winter with a grid tied CS through a windyboy 2500.
Dick
Logged

Aiming to reduce dependency on 'mains energy'. Own bio for 40k miles, solar water heating (DIY),  CHP done blog at http://www.dpks.co.uk/CHP/main.htm (not always up to date!)
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 6465



WWW
« Reply #3 on: March 01, 2011, 10:13:01 PM »

 a bid off topic perhaps  ,  say one has a 5 kw Generator an rectifies  is it than essential to use a 5 kw GTI ?

If i only have a say 2 kw GTI ? Will the generator destroy the GTI ?

Thanks Billi
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
guydewdney
Hero Member
*****
Offline Offline

Posts: 3859



« Reply #4 on: March 01, 2011, 10:22:42 PM »

a bid off topic perhaps  ,  say one has a 5 kw Generator an rectifies  is it than essential to use a 5 kw GTI ?

If i only have a say 2 kw GTI ? Will the generator destroy the GTI ?

Thanks Billi

yes. why would you try to under-spec is so much?
Logged

Pic of wheel on day 1
7.2kW Waterwheel and 9.8kW PV
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 6465



WWW
« Reply #5 on: March 01, 2011, 10:28:01 PM »

....  just thinking of converting my/ or in generall  old cheap 3.5-5  kw  AC diesel generator    to run through a  GTI and couple it to off grid  houses  ,  but the costs off a big GTI are the pain   

Billi
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
jotec
Hero Member
*****
Offline Offline

Posts: 611



WWW
« Reply #6 on: March 02, 2011, 08:07:05 AM »


billi you say "to run through a  GTI and couple it to off grid  houses" why do you need a GTI if you are off grid? standard inverters are much cheaper.

With the windyboy 2500 I can program it to our put the wattage I want at any voltage. My PMA is good for 3kw but I have set WB to a max of 2kw so that the gti  is not over driven as, though it is 2500W it is not designed to do this continually. I run at 1600w at 290V DC as I have discovered that this is the most economical on fuel with a good heat output and covers most of out load most of the time. I have still more experimenting to do and might reduce the voltage but keep the wattage as reduced volts mean less revs on the lister.

So in answer to your question I would say yes you can run a 5kw through a 2kw GTI but as Guy says why under spec so much? Far better to match the components closer.
Dick
Logged

Aiming to reduce dependency on 'mains energy'. Own bio for 40k miles, solar water heating (DIY),  CHP done blog at http://www.dpks.co.uk/CHP/main.htm (not always up to date!)
tony.
Guest
« Reply #7 on: March 02, 2011, 06:21:29 PM »

have a look at an old thread.

http://www.navitron.org.uk/forum/index.php?topic=10441.0

tony
Logged
billi
Global Moderator
Hero Member
*****
Offline Offline

Posts: 6465



WWW
« Reply #8 on: March 02, 2011, 08:38:46 PM »

Dick ,


Quote
billi you say "to run through a  GTI and couple it to off grid  houses" why do you need a GTI if you are off grid? standard inverters are much cheaper.

I believe a Gridtied inverter  with a rectified  generator ( diesel driven )  makes a  good Backup or constant running generator for us off gridders  and viable to DIY  with some knowledge  and this setup then incorporated in our off grid network  Grin ( if one has a  inverter /charger  combi unit that is designed for it ) results in a more harmonic  setup 

Cause we then can use the clean power from the generator  that travels  to our house loads  and in parallel the overproduction is feed into "our grid" = the battery through our Off grid inverter/charger

Hard to understand  , but worth a thought i think

Anyhow just had a look  GTI like a sunny boy 3300  is about 1100 GBP   so not too bad



Billi
Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
michiel
Full Member
***
Offline Offline

Posts: 181


Gaia


« Reply #9 on: March 03, 2011, 07:49:12 AM »

Thanks all for the feedback.

OK, so my brand new 1ph ST5 generator was not the best choice for grid tying the cs!
Should have done some homework first!!

Somebody has advised me that if I use an Aurora Wind Interfase, to rectify and smooth the AC , coupled to an Aurora GTI it should work.
This is going to cost in excess of 1500 though.

As I have a very large demand for hot water here, I recon the best solution would be to just feed the generation via a 3Kw immersion, together with recovered heat from exhaust and engine, into the 1000lt buffertank.

Another question for the panel here,

My ST5 1ph generator has a U1 and U2 terminal for wiring up.
Which one should I treat as L and which one the N?
Probably not important now, if I am just wiring direct to immersion, but would still like to know.
Instructions do not clarify this.

Michiel
Logged

11kW Gaia-wind, 3.85kW PV mounted on 3x trackers, Borehole fed 32kW GSHP, 10m^2 Flat plate Solar, 100x58mm (Navitron) ET's, 1000Lt heat store, WVO Lister CS CHP, WVO powered VW Caddy, 4 chickens and 3 ducks, (edit, ducks no more, taken by fox!)
qeipl
Sr. Member
****
Offline Offline

Posts: 337



WWW
« Reply #10 on: March 03, 2011, 08:19:52 AM »

Michiel,

I had a similar problem to solve with my AC hydro turbine and solved it with a rectifier/capacitor for under 100.

See here for details - http://www.navitron.org.uk/forum/index.php/topic,5847.msg76042.html#msg76042

Malcolm
Logged

Our Money: how to shrink government, boost business, eliminate poverty, and make the economy work properly for everyone.

A book for people who are perplexed about the economy.
Available from Amazon in paperback and eBook.
jotec
Hero Member
*****
Offline Offline

Posts: 611



WWW
« Reply #11 on: March 03, 2011, 09:13:03 AM »

Billi
Ah that makes sense. Just wondering though, I seem to remember a post where someone wanted to use a GTI when the grid was down.  Something along the lines of "Could a small inverter be used to start the gti and so use the power" IIRC the feeling was that there would not / if there was not/  sufficient load to sink all the output from the gti  this could cause the release of the magic smoke.
Might be worth investigating.
Dick
Logged

Aiming to reduce dependency on 'mains energy'. Own bio for 40k miles, solar water heating (DIY),  CHP done blog at http://www.dpks.co.uk/CHP/main.htm (not always up to date!)
guydewdney
Hero Member
*****
Offline Offline

Posts: 3859



« Reply #12 on: March 03, 2011, 06:40:16 PM »

That was me... (tiny pure sine wave inverter giving the big inverter a 'fake' mains.
Logged

Pic of wheel on day 1
7.2kW Waterwheel and 9.8kW PV
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2013, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!