240v generator stepped down to 120v inverter

Falcon · September 2013

Hi everyone, new guy here. I've lived off the grid in CO Rockies for 15 years now using a Trace 4024 inverter. I also have a Kohler 12K/50A backup generator. I have been feeding the inverter off one leg of the generator, which has bothered me because (I think) I'm only using half the current available from the generator, which means when charging, and particularly equalizing the batteries, I'm limited to 25A for charging and household power. It also concerns me that I'm running the generator unbalanced by doing this, although it doesn't seem to have caused any problems at this point.

What I've been considering is using this http://www.amazon.com/VOLTAGE-TRANSFORMER-COUNTRIES-VOD-10000/dp/B00126ULLE/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1380293807&sr=1-1-catcorr&keywords=10%2C000+watt+step+down+transformer step down transformer between the generator and the inverter. Aside from the fact it's only 10K, which I'm not sure is an issue, is there any other issue I should be concerned with?

Obviously I could stack another inverter or go to a 240v inverte (wish I had done this in the first place), but of course we are talking 10 times the cost.

Additionally, I know I have two AC inputs on the 4024, but as far as I can tell only one of those is for generator use, not connecting both legs of a 240v input from a single source.

Thanks for any help or opinions.

BB. · September 2013

Re: 240v generator stepped down to 120v inverter

Outback (and Schneider/Xantrex?) make some transformers specifically for balancing 240:120 VAC (input/output/shared power, etc.):

Outback Power FW-X240 Auto Transformer
Outback Power PSX-240 Auto Transformer

Outback also has a nice manual to show various configurations that they can support:

Manual for Outback 240 transformer

It should work well for for your needs--The 240 is "only" a 4kVA unit--So you may have to get a larger transformer elsewhere if you want more current.

You may also want to look at getting a second, smaller genset... I like to suggest you want to run a genset on battery charging at a minimum of around 50% of nameplate capacity... As you drop below 50%, fuel flow remains pretty close at 50% of rated fuel flow (for gasoline, propane, spark ignition gensets). And running diesels at less than ~40% to 60% of rated load can result in "wet stacking", carbonizing, cylinder wall glazing.

What is the AH and voltage rating of your battery bank... There is usually not a good reason for running charging current much above ~10-13% rate of charge (or over ~20-25% ever) for standard flooded cell deep cycle batteries.

If you have a 12 kVA genset and are only using 3-4 kVA maximum--You can probably double your fuel efficiency by either jacking the loads >6 kVA or using a smaller genset.

Of course, a lot of this depends on how much you run your genset... if it is only a few dozen hours a year, then it is probably not worth spending too much on efficiency, 2nd genset, etc. If you run for weeks+ during the winter (and/or during summer A/C and/or family time)--Then looking at fuel conservation is usually worth the investigation.

Sort of the range of a gasoline engine--You can be in the 3-6 kWH per gallon range--That being pretty efficient... Or you can be 1/2 that or below, and spending a lot of extra money on fuel costs. I even suggest people buy an old AC utility meter and put it on their genset output and see what their kWH/Gallon fuel efficiency is. A little math/spread sheet work may save you money and noise/smoke/maintenance over the long haul.

-Bill

techntrek · September 2013

Re: 240v generator stepped down to 120v inverter

I see no reason why you can't use the transformer you linked to, attached to the two legs (L1 and L2) of the generator output. I don't like the mostly exposed lugs on the front of it, and for safety reasons I would enclose the front (making sure not to block any vents).

I agree with Bill, I'd bet most of the time you should be using a smaller inverter-genset. I discovered the same over time, first buying a 12 kw monster "so I could run everything I want", then discovering that the genset makers don't like talking about how expensive it is to feed one of them over long outages - or long winters in your case. Considering that most household loads are below 3 kw (and usually below 500 watts overnight) it only makes sense to look into what Honda and Yamaha have to offer. A EF2400is Yamaha inverter-genset is now my 3rd backup power source. My 12 kw genset is now only used to power my well pump and water heater during longer outages.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Hi Bill, thanks for the reply. Perhaps I wasn't clear in my original post, if so my apologies.

The Trace (Xantrex) SW4024 is a 24v, 4000W continuous/8000W surge, true sine wave inverter.

I have 12 L-16HCL 6V/420Ah batteries wired series and parallel for 24v/1260Ah. Genset is a Kohler 12Kw 240v/120v 50A LP.

I'm not sure why you suggested a smaller genset in reply to my question. My previous genny was a 10Kw (my apologies, it was an 8.5Kw, been a few years) Kohler, and it actually used more fuel for the same power output. A look at the lbs per hour of fuel (propane) burned per amp on the manufacturers charts is sufficient to determine the larger gensets better fuel efficiency, and my real world usage has verified this. Also, I live at 9000 feet elevation, so gen output is reduced significantly due to the lack of oxygen compared to sea level. I've run off of smaller generators when servicing the primary genset, and they cannot keep up with the normal demand of charging my battery bank, and supplying household power at the same time, much less equalizing. Equalizing alone requires 30A.

Since battery life and maintaining capacity is dependent on being able to equalize, and that is solely a function of high charging amps, all your comments on generator sizing seem counter intuitive.

In any event, I need more available amps, not less, which is why I supplied the info on a 10Kw transformer. I'm already getting 6Kw (minus the loss for altitude) so I'm not sure how the 4Kw transformer was relevant. Maybe I'm missing something, if so I welcome being corrected.

Again, my question was if anyone could see any issues (mainly damaging my inverter) with using the 10Kw transformer at the link I supplied to step down the 240v to 120v in order to increase the available amperage to my system while balancing the load on my generator. Thank you.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

techntrek wrote: »

I see no reason why you can't use the transformer you linked to, attached to the two legs (L1 and L2) of the generator output. I don't like the mostly exposed lugs on the front of it, and for safety reasons I would enclose the front (making sure not to block any vents).

I agree with Bill, I'd bet most of the time you should be using a smaller inverter-genset. I discovered the same over time, first buying a 12 kw monster "so I could run everything I want", then discovering that the genset makers don't like talking about how expensive it is to feed one of them over long outages - or long winters in your case. Considering that most household loads are below 3 kw (and usually below 500 watts overnight) it only makes sense to look into what Honda and Yamaha have to offer. A EF2400is Yamaha inverter-genset is now my 3rd backup power source. My 12 kw genset is now only used to power my well pump and water heater during longer outages.

I agree that it is a bit exposed, but that should not be a problem in my utility room.

Going to a smaller system is not an option. I definitely use what I have. As stated, I live off the grid, and in addition to running the normal household appliances I run a well pump and a home workshop. I also have a family. I've used a 2500w and 5500w genny for short periods and neither of them were nearly sufficient for my needs. I've also designed and installed systems for small spec homes I've built and found that the minimum for a functional household is 8Kw, and that is the general consensus among all the installers in this area, and the homeowners. I'm wondering if perhaps I've fallen into a minimalist community here and should expect to be run off

.

Blackcherry04 · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

I'm wondering if perhaps I've fallen into a minimalist community here and should expect to be run off .

Thats pretty funny, we need some levity on here from time to time. Most here have come to realize that there are more ways to skin a cat than one. I have a 20 KW, runs perfect on 2.2 gallons of fuel a hour. I have 86 amps @ 240 V, then again I am paying $10.00 a hour to do it. My other generator is a Inverter Generator that will run 7 hours on a gallon for $4.00 vs $70.00, In a perfect world you'd be able to dial in exactly what you need. Why would I produce 86 amps when I need less than 10 amps, 75% of the time.

9000 ft is pretty high, come down to sea level every once in a while and see the rest of us live.... lol

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Blackcherry04 wrote: »

Thats pretty funny, we need some levity on here from time to time. Most here have come to realize that there are more ways to skin a cat than one. I have a 20 KW, runs perfect on 2.2 gallons of fuel a hour. I have 86 amps @ 240 V, then again I am paying $10.00 a hour to do it. My other generator is a Inverter Generator that will run 7 hours on a gallon for $4.00 vs $70.00, In a perfect world you'd be able to dial in exactly what you need. Why would I produce 86 amps when I need less than 10 amps, 75% of the time.

9000 ft is pretty high, come down to sea level every once in a while and see the rest of us live.... lol

Valid comments. Since I primarily use my genny to charge my batt bank and run my deep well pump to fill a 500 gal cistern, when it's running I'm putting a significant load on it without even powering basic household needs, much less if the washer, dryer and dishwasher are going along with the house pressure jet pump. None of which are optional. Then there's my shop which includes large power tools and a welder.

I visit sea level often, usually in winter and someplace tropical. :cool:

Cariboocoot · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

I have 12 L-16HCL 6V/420Ah batteries wired series and parallel for 24v/1260Ah.

So three parallel battery strings, which is not good, and a massive battery bank which requires more current than the SW4024 can push for charging. Also not good. 3.5 kW of gen alone to charge that bank.

Equalizing alone requires 30A.

Can't imagine why, since EQ is a constant elevated Voltage on an already fully charged battery bank.

Oh yes; because the regular maximum charge rate can't do the job and EQ is being used to correct repeated insufficient charging. Not good.

No wonder you need such a large generator. Have you considered going with a new inverter and upping the system Voltage to 48 to take the current down and make things easier all-around?

As for using an autotransformer, this is not a good idea with a generator as there can be problems with residual magnetism causing unbalancing of the legs rather than preventing it.

But here's another idea: shift the loads to one leg and the charging to the other. This will require some re-wiring of the AC input from the gen and a manual transfer switch to take the household off the inverter output and put it on L2-N of the gen instead of expecting L1-N to run both loads and charging.

Always more than one way to do it.

Blackcherry04 · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

Valid comments. Since I primarily use my genny to charge my batt bank and run my deep well pump to fill a 500 gal cistern, when it's running I'm putting a significant load on it without even powering basic household needs, much less if the washer, dryer and dishwasher are going along with the house pressure jet pump. None of which are optional. Then there's my shop which includes large power tools and a welder.

I visit sea level often, usually in winter and someplace tropical. :cool:

I hear you, I do use my big generator ( over 2400 hrs in 6 years ) but I'v gotten more picky when I do it and it's for a purpose. The fact that you can now parallel a couple of small generators these days is something you cannot over look. PV has also dropped into a price range that adding more and using more during daylight hours make's sense.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Blackcherry04 wrote: »

I hear you, I do use my big generator ( over 2400 hrs in 6 years ) but I'v gotten more picky when I do it and it's for a purpose. The fact that you can now parallel a couple of small generators these days is something you cannot over look. PV has also dropped into a price range that adding more and using more during daylight hours make's sense.

Yes, and that's all fine till you're PV charge controller goes down etc. My philosophy has always been a redundancy that can cover the max power needs, and I've never been sorry, and been thanked several times. One local installer would refuse to put in a generator stating that he would rather use the money for more PV. I've thanked him a couple times for giving me the customers to sell and install a generator to.

Honestly, when calculating out even a minimal whole house system I've never come across a situation where anything less than 8K was practical. Because as soon as you start running appliances and a well pump while charging, you might as well throw that 2500w generator in the trash, because you are never going to charge a usable battery bank and run the appliances at the same time. Not to mention how hard that is on electric motors. And if you use an LP genset plumbed to your bulk tank, your costs are reduced significantly.

Blackcherry04 · September 2013

Re: 240v generator stepped down to 120v inverter

You'v got a pretty old Inverter, it's time for one with " Generator Support " and move up to 48 V. Technology changes, these days it's not how big my Inverter is or how big my generator is, it's how can they both work together and give me the outcome I need.

westbranch · September 2013

Re: 240v generator stepped down to 120v inverter

OK, maybe a bit slow this afternoon, having trouble visualizing how you have pulled together a 'redundant-ized' system with only 1 Trace4024.

I am kind of following your thinking by having redundant (parallel) Arrays, CC's and Battery banks, but it sounds like you only have one CC and 1 Inver/charger??? Where is your 8K coming from?

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Cariboocoot wrote: »

So three parallel battery strings, which is not good,

Could you clarify this? I've never run across this being an issue before.

and a massive battery bank which requires more current than the SW4024 can push for charging.

I have no problem charging it for 15 years and one rebuild on the inverter.

Also not good. 3.5 kW of gen alone to charge that bank.

Why is that an issue?

Can't imagine why, since EQ is a constant elevated Voltage on an already fully charged battery bank.

Oh yes; because the regular maximum charge rate can't do the job and EQ is being used to correct repeated insufficient charging. Not good.

It doesn't require a constant 30A, but it does require an initial 30A to get it up to the equalize voltage of 31 volts. Which no matter which way you slice it still requires a larger generator. And I'm not sure where you come up with "insufficient charging", I keep my batteries topped off. Sulfate buildup is going to happen regardless. This is a prescribed regular battery maintenance from both battery manufacturers and high end inverter/charger manufacturers such as Xantrex. I got 11 years out of my last bank of batteries that endured a very high number of discharge/charge cycles in a full time family household, I think I'm doing just fine in that dept.

No wonder you need such a large generator. Have you considered going with a new inverter and upping the system Voltage to 48 to take the current down and make things easier all-around?

I've certainly considered going to a 240v inverter, but I see no reason to go to a 48V system, I don't have line drop from the batteries as all connections use 000 welding cable, it would require me to either add 4 more batteries or lose 4, my panels are 10 feet from the inverter, and battery output current is not my issue at this point.

As for using an autotransformer, this is not a good idea with a generator as there can be problems with residual magnetism causing unbalancing of the legs rather than preventing it.

Interesting, considering Xantrex and Outback sell them for their units. Can you elaborate a bit more on where this residual magnetism is coming from?

But here's another idea: shift the loads to one leg and the charging to the other. This will require some re-wiring of the AC input from the gen and a manual transfer switch to take the household off the inverter output and put it on L2-N of the gen instead of expecting L1-N to run both loads and charging.

Interesting idea, but entirely impractical for a user friendly system that anyone in my family can operate seamlessly.

Always more than one way to do it.

True enough. IME rarely is there more than one correct way.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

westbranch wrote: »

OK, maybe a bit slow this afternoon, having trouble visualizing how you have pulled together a 'redundant-ized' system with only 1 Trace4024.

I am kind of following your thinking by having redundant (parallel) Arrays, CC's and Battery banks, but it sounds like you only have one CC and 1 Inver/charger??? Where is your 8K coming from?

The generator is redundant to the PV/wind/battery bank/inverter. IOW if part or all of that go down, you can still power your house.

As far as 8K, I'm assuming you're referring to the generator? Start adding up appliances, well pump and battery charging plus a workshop.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Blackcherry04 wrote: »

You'v got a pretty old Inverter, it's time for one with " Generator Support " and move up to 48 V. Technology changes, these days it's not how big my Inverter is or how big my generator is, it's how can they both work together and give me the outcome I need.

Old? lol. I see no reason to go to 48v. The reason most people go to 48V is due to line drop from the PV array. As far as generator support, my inverter is fully programmable for the generator. Apparently you are not familiar with this model.

NorthGuy · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

What I've been considering is using this http://www.amazon.com/VOLTAGE-TRANSFORMER-COUNTRIES-VOD-10000/dp/B00126ULLE/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1380293807&sr=1-1-catcorr&keywords=10%2C000+watt+step+down+transformer step down transformer between the generator and the inverter. Aside from the fact it's only 10K, which I'm not sure is an issue, is there any other issue I should be concerned with?

This particular model may be very bad quality according to this Amazon review.

westbranch · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

The generator is redundant to the PV/wind/battery bank/inverter. IOW if part or all of that go down, you can still power your house.

As far as 8K, I'm assuming you're referring to the generator? Start adding up appliances, well pump and battery charging plus a workshop.

Ok got it now , I assumed you had more than 1 CC as per your comment

Falcon wrote: »

Yes, and that's all fine till you're PV charge controller goes down etc. My philosophy has always been a redundancy that can cover the max power needs, and I've never been sorry,

What size PV array do you have?

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

NorthGuy wrote: »

This particular model may be very bad quality according to this Amazon review.

Yea good point i saw that

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

westbranch wrote: »

Ok got it now , I assumed you had more than 1 CC as per your comment

What size PV array do you have?

I actually do have a spare 3000w24v inverter and a spare CC.

I have 1Kw. Getting ready to upgrade to new panels, hopefully around 1.5K depending on price.

westbranch · September 2013

Re: 240v generator stepped down to 120v inverter

What CC do you use? MPPT? Can it handle 2.5 k of PV?

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

westbranch wrote: »

What CC do you use? MPPT? Can it handle 2.5 k of PV?

I wont be keeping old panels, they will be going to a friend. So I'll only have 1.5K. CC is a Trace C40. I'll have to get a new CC with the new panels.

Cariboocoot · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

Could you clarify this? I've never run across this being an issue before.

Parallel battery strings = parallel current paths. Changes in the resistance between them due to wire lengths or connector resistance can add up to different amounts of current in/out on each string. This is a problem that can get worse over time, not one that just suddenly shows up. More strings and/or lower Voltage = greater chance of problems developing. Take a look at the Smart Gauge battery wiring diagrams as an example: http://www.smartgauge.co.uk/batt_con.html

Large battery bank = large current needed for Bulk charging. The more power stored/used as current rather than Voltage the more power goes to heat - being wasted. This is why people go to 48 Volt systems.

Not knowing the load demands I can't say whether or not you need such a large bank (over 24kW hours). But if you do, having it at half the Amp hours and twice the Voltage is advantageous. The down side to 48 Volt system is that the necessary over-current protection and disconnects can be hard to find/expensive. Reconfiguring can run into problems with array rewiring (two 30 Vmp panels in series fine for 24, not enough for 48 ) and in the case of three parallel battery strings they don't divide out evenly into 48 Volts.

I have known many people whose battery bank "worked fine" for a number of years, simply because it was so large that the minute but chronic undercharging did not become significantly noticeable until those years passed.

Interesting, considering Xantrex and Outback sell them for their units. Can you elaborate a bit more on where this residual magnetism is coming from?

Transformer saturation. This is not a problem with inverter output as there is no rotating mass as with a generator. If you look at the mess of Outback wiring diagrams you will see some with series-stacked inverters to provide 240 VAC and autotransformer to balance loads between them wherein the transformer needs to be cut out of the system when using a 240 VAC gen on the AC IN.

Interesting idea, but entirely impractical for a user friendly system that anyone in my family can operate seamlessly.

I know what you mean; telling someone "start the gen, flip this switch, turn that dial, read that meter ..." is going to get you a dead system more likely than not. However, it may just be possible to use an automatic transfer switch or AC relay to do the same thing: gen fires up, activates relay to take loads off inverter output and on to gen L2-N while the input to the inverter functions as normal. Might not be as seamless, however.

True enough. IME rarely is there more than one correct way.

Lots of different methods to achieve the end result. The "correct" one is what works best for a given application, but there are degrees of "correctness".

Cariboocoot · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

I wont be keeping old panels, they will be going to a friend. So I'll only have 1.5K. CC is a Trace C40. I'll have to get a new CC with the new panels.

What I would recommend for solar on 1260 Amp hours @ 24 Volts:

Two 80 Amp MPPT charge controllers, each with 2kW of array on it.

Another reason to go to 48 Volts: same amount of power can be handle by one controller.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

There are some compelling arguments for 48v here, unfortunately the batteries are the main roadblock at this point, dropping 4 and reducing my amp hours, or adding 4 new ones to a bank thats 4 years old just doesn't appeal to me.

Thanks for the battery connection link, I may do some mods to mine. It's already diag configured like #2 config, but I may do some more balancing connections.

Blackcherry04 · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

Old? lol. I see no reason to go to 48v. The reason most people go to 48V is due to line drop from the PV array. As far as generator support, my inverter is fully programmable for the generator. Apparently you are not familiar with this model.

I know enough about them, I got my first Trace SW back in 1998-99. They are old technology and the way things are implemented is different. One thing different is the efficiency is just a little better across a larger range. If you can keep it going, more power to you. If you ever had 12 V and went to 24 V you know the difference, going to 48 is the same, the loads much easier on the system. By the way, a SW 4024 calls for 4/0 cables.

SW4024 or W, K 214 Amps 267 Amps NEC , #4/0 AWG/107 mm2

mike95490 · September 2013

Re: 240v generator stepped down to 120v inverter

Cariboocoot wrote: »

......As for using an autotransformer, this is not a good idea with a generator as there can be problems with residual magnetism causing unbalancing of the legs rather than preventing it.....

I've got no idea how this could happen, transformers have soft iron cores that do not generally become magnetized. I suppose if you had circulating DC currents, that could saturate the core, and cause wonky things to happen, but I think that in nearly all occurrences, there would be a fault somewhere causing core saturation, and still can't magnetize the core.

Many generators rely on residual magnetism to initiate the power up process, and if loads stay connected while the generator spins down, it can blank the core, and require a "re-flash" to magnetize it.

Cariboocoot · September 2013

Re: 240v generator stepped down to 120v inverter

It shouldn't happen, but it does. This is not something that occurs in a constant state but rather as generation and/or loads change. It was a big problem back when I was servicing farm equipment (motors) that were being run from generators. It doesn't seriously affect operation of them (might shorten lifespan a bit) but I wouldn't want to take the same risk with electronic components getting a momentary shot of high Voltage. Rather like line spikes; most of the time, no problem, but there's always that one chance.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Blackcherry04 wrote: »

I know enough about them, I got my first Trace SW back in 1998-99. They are old technology and the way things are implemented is different. One thing different is the efficiency is just a little better across a larger range. If you can keep it going, more power to you. If you ever had 12 V and went to 24 V you know the difference, going to 48 is the same, the loads much easier on the system. By the way, a SW 4024 calls for 4/0 cables.

SW4024 or W, K 214 Amps 267 Amps NEC , #4/0 AWG/107 mm2

Good catch on the wire size. I made mine 15 years ago and they are 0000. The last wires I made up for a friend were 000, as were the several sets prior to that, so 000 was in my head.

A new inverter is in future plans just because I know they go out, and I don't know if the "old" 4024 can be serviced. After reflecting on things here, it has seen a lot of use. However, mine and several others around here are still going strong, they were the best in their day and seem to be extremely reliable, barring being fried by freak lightning storms that no amount of protection will prevent.

I'm still not convinced 48v is a better way to go, although I'm trying to be open minded about it, and if I go that way I cant use the 24v inverters I have as backup.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Cariboocoot wrote: »

It shouldn't happen, but it does. This is not something that occurs in a constant state but rather as generation and/or loads change. It was a big problem back when I was servicing farm equipment (motors) that were being run from generators. It doesn't seriously affect operation of them (might shorten lifespan a bit) but I wouldn't want to take the same risk with electronic components getting a momentary shot of high Voltage. Rather like line spikes; most of the time, no problem, but there's always that one chance.

Could this be prevented with proper chassis grounding? And/or a breaker between the transformer and inverter?

Cariboocoot · September 2013

Re: 240v generator stepped down to 120v inverter

Falcon wrote: »

Could this be prevented with proper chassis grounding? And/or a breaker between the transformer and inverter?

A breaker would have no effect as it is a Voltage problem, not a current one.
You can run into trouble with grounding too, as a 240 VAC gen typically has a center neutral which may already be grounded, so if you run the output through a step-down transformer and ground one side of its output there could be Voltage potential between the two grounds. This would mean current flow (hopefully within Earth only) and power loss. Use of a autotransformer that typically has the two sides connected as neutral and grounded would be better, but you could still have issues with the "built-in" neutral of the gen if it is bonded to ground.

Best-case would be the autotransformer with its center as neutral and bonded to ground while making sure the gen's neutral is not connected to ground (no N-G bond at generator) but the gen's ground is.

These things don't always behave in quite the way we would expect.

BTW, the SW4024's come up often on the forum. Usually as "mine's broken; where can I get it fixed?". Unfortunately that is becoming more difficult but there are still some people out there doing it.

Falcon · September 2013

Re: 240v generator stepped down to 120v inverter

Cariboocoot wrote: »

A breaker would have no effect as it is a Voltage problem, not a current one.
You can run into trouble with grounding too, as a 240 VAC gen typically has a center neutral which may already be grounded, so if you run the output through a step-down transformer and ground one side of its output there could be Voltage potential between the two grounds. This would mean current flow (hopefully within Earth only) and power loss. Use of a autotransformer that typically has the two sides connected as neutral and grounded would be better, but you could still have issues with the "built-in" neutral of the gen if it is bonded to ground.

Best-case would be the autotransformer with its center as neutral and bonded to ground while making sure the gen's neutral is not connected to ground (no N-G bond at generator) but the gen's ground is.

These things don't always behave in quite the way we would expect.

BTW, the SW4024's come up often on the forum. Usually as "mine's broken; where can I get it fixed?". Unfortunately that is becoming more difficult but there are still some people out there doing it.

Since the derail is already in place, and a new inverter is beginning to seem like the safest and most practical option, how do the Magnum inverters stack up against my old 4024? Looks like the control panel is a separate purchase? Does it have more/less control parameters? I'm reading the pdf manuals and it seems comparable.

240v generator stepped down to 120v inverter

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