can I add a transformer to the output of 5000 watt MSW inverter 220vac output

[musselbeach]

Hi,
I need some help, in finishing our house off grid power system.
When I bought a Generac 7kv propane generator (220/110v split phase output) which I have installed, it came with a transfer switch which is designed to switch from hydro to generator when hydro drops out.
I thought I maybe able to hook up my solar, wind, battery power system through a 24vdc to 220v ac modified sine wave 5000 watt inverter which I have already bought. but when I received it it only had 2 wire 220v output not the 220/110 split phase output?? which has 4 universal plugs for the 220vac output (only 2 wires hooked up to each) they are parallelled up from 4 diff. cct boards.
I am not familiar with the design but in the instructions it says it raises the 24vdc to 300vdc then converts this using advanced MOSFET transistors in a full bridge configuration. It also says its capable to start and run difficult reactive loads.
I am wondering if I bought a 220v to 220/110v split phase transformer  and put that between the inverter and the transfer switch would it work with out to much effeciency loss??I do not want to spend more money on the transformer if the whole things not going work or distroy the inverter.
Any help I can get would br greatly appreciated.
Thanks Ron Whorley
musselbeach.whorley@gmail.com
canada

[Watt]

Welcome to Otherpower.

What kind of waveform does this MSW inverter produce as output?  Is it a square wave, 'stepped' square wave or a saw toothed waveform?   Reason I ask is because a transformer, like an inductive motor, works by flux density changes.  True Sine waves have voltage/current changes charting longer and smoother which allow more dense flux to flow through the core.  After the wave peaks and starts to fall, current flow reverses and induces a current into the secondary ( collapsing field ). EDIT * Square waves of various types have varying voltage increases mostly in less time which in turn cause flatter curves which are not indicative to flux changes. * Shouldn't say this really.  The voltage/current change is good but what I should say is because the quick voltage change, core losses are greater due to more time when there is no flux changes.  In a hz cycle, if 40 percent of that cycle is actual voltage change, 60 percent of that cycle flux density is not changing because current is staying ' still ' if that makes since.
What does a True rms meter display as output connected to your MSW inverter?

I'm sure others, such as Flux, can describe far better effects than I can.

Truthfully, you will be better off with a true sine wave inverter.  Are you in a 60 hz country or a 50 hz?  This inverter, being 220v two wire, seems to be a 50hz output to me.  And yes, you will have losses with a tranformer no matter which type you use.  More so with a less pure wave form.

[Watt]

Must have reached the modify limit or time limit to modify.  I was trying to edit another screw up which says current staying still.  I should have typed current staying equal with flux staying equal and heating the core.  

[ghurd]

Ron,
Do not kill the messanger.

You purchased a "24vdc to 220v ac modified sine wave 5000 watt inverter".
That is what you got.

Guessing it was purchaed on ebay, cheap, it came from China, and you are in the US or Canada?

Is it 50 or 60 Hz?
(makes no difference, except to point out there are major differences in the world's grid)

The next issue is the grounding system.
It is a big issue.
It is a very big issue.

All I am saying is do not connect the inverter to anything (at all) until you totally understand the items you are dealing with.
G-

[Watt]

Here is a link that may explain a bit of our conversation by PM.

http://www.ultracad.com/articles/rms.pdf

Hope this helps if you have time to read.

[fabricator]

That inverter is NOT split phase, there is no way to get 110 out of it, it also probably has a floating ground which is not suitable for a residential system.

[ChrisOlson]

When I bought a Generac 7kv propane generator (220/110v split phase output) which I have installed, it came with a transfer switch which is designed to switch from hydro to generator when hydro drops out.

Unfortunately, you already got a problem if you're trying to use a grid-tied Generac for off-grid power.  Sell the thing and get a real off-grid generator.  I've already been there, done that, and it does NOT work.

When you say 7 kW, I assume you got the cheaper CorePower unit.  But the problem with it is that it is not the transfer switch that does the sensing for auto-start of the generator.  It is the generator controller itself that does the sensing.  And it needs clean, stable utility power to work.  If you try to feed that gen controller with a transformer, MSW inverter, or anything but pure sine 60 Hz split phase power, it won't work.

I went 'round the Mulberry Bush several times with Generac and Allied Generator (Authorized Generac Service Center) on how to set up auto-start on a CorePower generator.  The solution is to spend double what you spent on the CorePower and buy an EcoGen, which is two-wire start and made for off-grid duty.  They won't even warranty the CorePower (or Guardian series) for off-grid use.

And please don't tell me you bought it at Home Depot or Menards because then you REALLY got a problem even getting service for it, or returning it to exchange it for the right unit for the job.
--
Chris

[Watt]

That inverter is NOT split phase, there is no way to get 110 out of it, it also probably has a floating ground which is not suitable for a residential system.

Just wondering?

If, not saying the idea of using this inverter is smart, he was to build/buy a 1 to 1 transformer with center tap secondary, this would effectively give him a neutral with advertised ratings Primary = L-L of secondary.  Common ( center tap ) to L he would get half of L - L ( advertised 220v / 2 = 110v ).  I do realize the losses involved and have not considered that in this example.  Now using this too as an isolation transformer, his residence is isolated from that inverter and he could build a bonded ground system off the secondary common center tap.  This transformer would be wound equal primary to equal secondary turns with the only difference being the center tap in that secondary coil.  I example " build " only because this gives a bit of room for loaded volts on secondary, shielding and flexibilty in a " regulated " secondary output.

As far as a floating ground with that inverter, this is really no different than a 3 phase delta generator with no center tap.  It's a matter preventing potential paths.

I Maybe way off here.  But... That inverter could possibly be a nightmare from the start as suggested.  What if.... 


Just curious.

[joestue]

@Watt, there's no reason you can't put a transformer across the output and get your center tapped 110/220vac.
And if you don't need voltage isolation then the transformer doesn't have to be very big, it only has to be big enough to supply the difference in current.

The problem with any cheap inverter is if the inverter's output is referenced to the battery input then it is effectively useless, and with transformer prices these days not worth buying a 5 kw transformer for.
OP should hook up a 5 watt light bulb from the battery to the 220vac out of the inverter, (both battery terminals, and both ac lines out). if it lights up then you will need an isolation transformer to use this inverter in a properly grounded system, and that is not worth the expense nor parasitic losses.

[musselbeach]

Thank for the info on
Generac control module not working on the MSW Voltage. I all ready tried getting info on the control box because I wanted to wire the battery charger to the out put of the generator instead of going through the transfer switch to the Hydro side, As at the present I am using it to supply power to the house until I can get my wind/solar system up and running.
What do you people think about the "Apollo True Sine Wave Inverter / Charger TSW3224", it has its own battery charger and transfer switch.
http://www.ecodirect.com/Apollo-TSW3224-3200-Watt-120-240-VAC-Inverter-p/apollo-tsw3224.htm
I can all ways use the other cheap inverter with a 220 to 110 volt transformer on the output to run the garage/work shop which I have to build a separate system for as it is 100 ft from the house supply.
The problem here in canada is we are very short on knowhow and experience in green off grid power systems and all the parts we have to buy off in the USA as up here they want double $ plus for solar panels etc.
I have all ready installed a smaller solar/wind/generator system for our cottage where my daughter is staying and it is working fine
all though we have to start the generator manually a little more often to top up the batteries once in a while until I can beef up the battery banks.

[Watt]

I stayed away from the specifics of that inverter.  I believe you should have a read of this page.  This example is why I am concerned with connecting anything cheap to anything I own.

http://ludens.cl/Electron/chinverter/chinverter.html

I searched for a couple of days to finally remember where and what I was doing concerning cheap inverters and stumbled on this site.  Hope it gives an idea of our concerns.

[ChrisOlson]

What do you people think about the "Apollo True Sine Wave Inverter / Charger TSW3224", it has its own battery charger and transfer switch.
http://www.ecodirect.com/Apollo-TSW3224-3200-Watt-120-240-VAC-Inverter-p/apollo-tsw3224.htm

Frankly, if you're going to be living with this system for a few years, and need 120/240 split phase power (which is a very good choice IMHO vs going just 120 volt), I'd spend the extra buck and do it right:
http://www.ecodirect.com/Xantrex-XW4024-p/xantrex-xw4024.htm

When you live off-grid and purchase an inverter, getting service and parts for it is important.  Inverters are machines with electronics, and Stuff Happens.  Since Schneider Electric (Square D) took over the RE line of inverters and equipment from Xantrex their technical support, service and parts availability are second to none.  You can contact Schneider with this page to find out who your closest Authorized Service Center is:
http://www2.schneider-electric.com/sites/corporate/en/support/contact/customer-care-contact.page

If you ever figure out a way to hack auto-start on that 7 kW Generac for an off-grid application,  let me know how you did it.  I found that freaking controller in the CorePower and Guardian series generators are sensitive as hell.  It monitors both legs of the split phase service and if either leg goes out of spec on freq or voltage it starts the generator, then the controller sends the signal to the transfer switch (I assume you got the Generac EZ Switch with it) to flip the contacts in the switch.  I tried feeding split phase power to it from my Xantrex inverters using the NC contacts in a relay, and having the GSM open the contacts when the inverter wanted gen start.  That all worked fine, but then when the gen came online you can't tap power off the load side of the transfer switch to feed the AC input on the inverter, because if you do you're feeding power in a loop thru you signal relay when the gen is isn't running.

Nor can you tap off power for the inverter's AC input on the gen side of the transfer switch, because then the controller sees power again and shuts the gen down.  The only way it would work was manual control, and I wanted automatic.  Finally took it back to where I got it from and raised holy hell because the salesman sold me the wrong unit for what I needed.  They took it back and sold me an EcoGen for twice the money.  And the EcoGen is also twice the generator.  The CorePower or Guardian is not designed to put the kind of hours on, long term, that you will accumulate on an off-grid system.  They're an intermittent duty standy gen, whereas the EcoGen is a low speed continuous duty prime power generator.

It's all live and learn.
--
Chris

[hydrosun]

A number of years ago an off grid customer bought a used generac generator and asked me to hook it up. We threw away the transfer switch and used the out put of the trace SW4048 relays to go across the manual starting switch. So we could program at what battery voltage the generator would start up. It's been working for the last 6-7 years just fine.
I've also installed several ecogen generators and they are definitely a nicer unit.
Chris

[ChrisOlson]

We threw away the transfer switch and used the out put of the trace SW4048 relays to go across the manual starting switch. So we could program at what battery voltage the generator would start up. It's been working for the last 6-7 years just fine.

Were you able to program all the gen start timers (24 hr, 2 hr, 15 min, and LBCO) with it set up that way?

The older Generacs, IIRC, had a two-wire start like a Kohler or Onan.  These new ones with the electronic controller that you have to "Activate" with a code to make them auto-start could maybe be hacked that way if you could tie into the manual switch.  But the manual switch is built into that confounded computer on it.
--
Chris

[musselbeach]

Thank you guys for all the input. I was hoping not to have to use the generac that often as I am putting in quite a large Battery bank and with the 1000 watt hrs. of solar panels for about 5hrs per day and 750w wind turbine (for winter use) and the fact that our house fridge,stove,water heater and generator all run on propane all I need is power for washing machine(once a week) 750 watt TV, and LED lighting thru out the house. We are facing south so we get a lot of sun thru the windows and have a good 90% efficients wood burner. Wood is free for us as well.
I have installed this Generic propane generator I thought if the Apollo was a good inverter it came with its own transfer switch and charger I could work around the  Generac control panel and if necessary just use it to bang up the batteries once in a while on manual.
My question still remains does anyone know of anybody that has any experience with them??
The Xantrex model 86-1010- 4000 is a little more than I need and the price and shipping charges is a little high for my budget at this time.
For the cottage installation we have been using a power bright 2300 watt 24 to 120v inverter which has been working now for 8 month and have no problems. It cost us $289.00 free shipping from Montreal and we are located on the west coast.
My daughter and her husband uses the microwave, florescent lights, toaster,hair dryer, TV, freezer and LED lighting system.
we have 4 230 watt solar panels and 500 watt wind turbine for Green power. But they also use propane for stove,fridge and hot water.

[ChrisOlson]

My question still remains does anyone know of anybody that has any experience with them??

Myself, I know nothing about the Apollo inverter.  I know of nobody that is using one for off-grid power.

The way I look at it, when it comes to off-grid power you got the Big Three - Xantrex, Outback and Magnum Energy.  When you get to the point of spending upwards of $2,000 or more on an inverter, it had better come with support, service and parts readily available for it.  You're in a different ballgame than a $289 throw-away unit.  The Big Three provide all the above.  Before I'd buy an Apollo inverter I'd find out where you can get these things for it.  If it's one of those deals where when something happens to it you have to box it up and send it away to Tim Buck Too, then wait 2-3 weeks to get a replacement (or repaired unit) back, well, that doesn't work all that well for off-grid power.  If there's an Authorized Service Center or dealer within a half day's driving range, and they carry the parts for it and provide service both under warranty, and out, then I'd look at buying one (maybe).

When we put in our upgraded power system this past summer, that was the main criteria and why I chose Xantrex over Outback.  I got a Xantrex dealer/Authorized Service Center only 170 miles away and they carry everything on hand, including a complete replacement unit if need be, to have me back up and running same day if one goes belly up.  I've had some inverters fail over the years.  In the summer it ain't too bad and you can get by.  In the winter, if one goes down, we have to have power to run our central forced air wood furnace blower and get water out of our well.  Sure, I can start the gen and bypass the whole thing.  But how many days in a row can you afford to do that in the dead of winter when it's 20 below zero F?  And without that inverter you can't use any of your turbines or solar panels to power your home unless you got stuff wired DC.  So all you got is the gen if that inverter quits.

When you got a 120 volt system you can go buy a cheap throwaway backup unit to get by until your main unit gets fixed.  When you go with 120/240 split phase that is not an option.  All you got is the gen.  The unit you got is not a split phase inverter, so that won't work for backup either.

 If you're going to spend close to $2 Grand I'd stick with one of the Big Three.  The reason they are the Big Three is because they have a proven track record of reliability and uptime.  You asked for opinions - that's mine.
--
Chris

[hydrosun]

The generac generrator was an older one that was bought for y2k and then sold to my customer for offgrid. I found the wires that went to the manual switch and put it on the generator start relaýYes it had the 2 hour, 24 hour voltage triggers set. I've no idea if that could be done with a neweer generatoThe big three inverter makers all had the same engineers design their best products. Robin and bob Gudgel have had there hand in many of those products.
Chris