converting modified sinewave to signwave

System · December 2011

Hi,
Recently I purchased a 5000 watt 24vdc to 220vac converter to run my off grid cottage and when I received it it had a European type 220vac 2 wire output and I require a 120/220 vac split single phase output to connect to a conventional north American household electrical panel. I am looking for a transformer with a 220v primary with an output of 120/220vac split phase which can provide these voltages. Which means the output of the transformer must have a 220v output with center tap which also provides 120v so I can connect both 220v sides (to the 2 hot leads) of the panel and the center tap to the neutral terminal. Our cottage at any one time will only require about 1200 watts as it has propane furnace,fridge,hot water tank and stove. The largest appliances would be a washing machine, furnace blower, vacume cleaner and microwave oven. We have led lighting throught out. Do you know where I could purchase a transformer to meet these requirements.
Another reason for the transformer is to have pure sinewave in the cottage.
Reguards
Ron Whorley

john p · December 2011

Re: converting modified sinewave to signwave

You simply CAN NOT convert a MSW inverter output with a transformer into a sinewave . It just aint that easy,or simple. IF it was there would be no need to design and manufacture far more expensive sinewave inverters.:D
I have no idea but if you can obtain such a splitting transformer where you live.

mike95490 · December 2011

Re: converting modified sinewave to signwave

Trace/Xantrex & Outback both produce a 120/250V autotransformer, but the problem is, a transformer will not work with mod-sine.
Sorry

Cariboocoot · December 2011

Re: converting modified sinewave to signwave

Welcome to the forum, Ron.

First up, adding a transformer to an MSW inverter won't give you sine wave output. It will also work rather inefficiently as MSW and induction loads (like transformers) notoriously do not get along. Second, if your inverter truly is "European" it's going to be 50Hz not 60Hz and it isn't going to work well with a lot of North American products.

Otherwise it is simply a matter of wiring in an autotransformer http://www.solar-electric.com/x-240.html the right way and connecting the center neutral lines to ground.

I know it's a lot of money, but I think you'd be happier all-round if you purchased an inverter that provided the right kind of power in the first place. Washing machines are big power users (1/3 HP high-torque induction motors) and vacuums & furnace blowers aren't far behind. Start-up demands for these can be enormous. The microwave is going to use 1kW + when running.

If you don't need 220/240 VAC don't buy it. There are lots of inverters capable of pure sine 120 VAC for not too much money, depending on your actual loads. Under the circumstances, I think your choice of a 24 Volt system is a good one. But honestly your looking at the $2,000 range for an inverter-charger that can supply pure sine in the 3 kW peak range. The cheapest possible solution would be something like this Exeltech 2kW unit: http://www.solar-electric.com/exxp1224vo20.html Or you could look around for some used equipment, but be careful with that as even if it is working now it may not be later and, depending on age, repair may be impossible.

john p · December 2011

Re: converting modified sinewave to signwave

Mike I dont know why you say you cant get a transformer to run from a MSW inverter . You certainly can it may not be a marriage made in heaven but in most cases it works. You will get buzz sometimes from poorly made transformers and they will run hotter, but its usually not excessive.
I have used for example have run 200w power amps from MSW inverters and never a problem
As for the 50hz to 60 hz I have never had a problem with that , Mabe there is for some users.
I use all 240v 50hz inverters bought in Australia and take themm to use in Philippines where they have same as USA 220v 60 hz and never a problem same for others I have sold them to.

mike95490 · December 2011

Re: converting modified sinewave to signwave

john p wrote: »

Mike I dont know why you say you cant get a transformer to run from a MSW inverter . You certainly can it may not be a marriage made in heaven but in most cases it works.....

That's a small signal transformer, but putting a 1KW load, via transformer & mod-sine, is not going to be pretty, I don't think.

Quick, somebody try it, and tell us.

I could not get an inverter to power up with a transformer attached, and I'd like to not try plugging in a big-n when the power is live.

ggunn · December 2011

Re: converting modified sinewave to signwave

mike90045 wrote: »

That's a small signal transformer, but putting a 1KW load, via transformer & mod-sine, is not going to be pretty, I don't think.

Quick, somebody try it, and tell us.

If you survive the experiment. I hope to be far enough away to be able to say, "What was that?" ;^)

john p · December 2011

Re: converting modified sinewave to signwave

A 200w per ch is not a "small signal transformer" thats a reasonable sized load and the inrush current is high as 32,000 uf of caps just after the transformer.
Sure its not a 1000 w load but its a reasonable load to give as example.

My main point was that Mike saying "you cant run a transformer from a MSW inverter" is wrong. Ok in some cases there may be problems but I have not encounted them in a way that would stop the inverter or transformer working.

boB · December 2011

Re: converting modified sinewave to signwave

mike90045 wrote: »

I could not get an inverter to power up with a transformer attached, and I'd like to not try plugging in a big-n when the power is live.

The transformer was most likely saturated in the wrong polarity when your inverter turned on and then turned itself off because of too much current. It can take a lot of current sometimes to bring larger transformers out of saturation when polarity isn't taken into account.

This is why AC circuit breakers sometimes trip when a big transformer is plugged in. It can depend on exactly when in the AC cycle they are plugged in.

Most of the old MSW inverters had big transformers on their outputs and they worked fine but would sometimes draw a lot of DC current at the next turn on if the first cycles' polarity and turn off conditions were out of whack. i.e., if the transformer is saturated in one direction, trying to drive it in that same direction draws a LOT of current but will eventually fix itself if the drive circuit is designed correctly.

boB

waynefromnscanada · December 2011

Re: converting modified sinewave to signwave

boB wrote: »

The transformer was most likely saturated in the wrong polarity. It can take a lot of current sometimes to bring larger transformers out of saturation when polarity isn't taken into account.

This is why AC circuit breakers sometimes trip when a big transformer is plugged in. It can depend on exactly when in the AC cycle they are plugged in.

boB

Thank you for that boB! It opened my eyes and explained a lot of things I've seen over the years, couldn't really explain, so just had to accept as the way things worked. I totally understand the concept, just never thought of it being involved this way before. Thanks for opening my eyes.

boB · December 2011

Re: converting modified sinewave to signwave

waynefromnscanada wrote: »

Thank you for that boB! It opened my eyes and explained a lot of things I've seen over the years, couldn't really explain, so just had to accept as the way things worked. I totally understand the concept, just never thought of it being involved this way before. Thanks for opening my eyes.

Yes, and some inverters will "remember" which polarity it was left in so that next time it is turned on, either charge or inverter portion, it will try to turn on the proper polarity to minimize the overload.

It's kind of a neat but very little known idea/concept.

boB

System2 · December 2011

Re: converting 220v to 110220 split phase using a transformer

The MSW inverter I bought is a 60 cycle but has an out put consisting of only 2 wires
I would like to convert that to hookup to 220 north american electrical panel as you know is 110 spilt phase on each side of the panel. The inverter instructios that came with it says you can run appliances with motors in tyhe as well as microwave ovens as long as it does not exceed the start up load. now I have copied a pdf file with a wiring diagram that shows a transformer hooked to an inverter.
http://www.victronenergy.com/upload/documents/Datasheet%20-%20Autotransformer%2032A%20-%20rev%2001%20-%20EN.pdf
your comment please??

mike95490 · December 2011

Re: converting modified sinewave to signwave

Can you give us a link to the inverter you have/are considering ?

Before you hook it up, be sure to have a spare can of this handy:

My belief is that the inverter will not like the large load presented by the transformer, and will release it's "Magic Smoke" when you try to connect it. A large inverter can easily power a small transformer, but I suspect a 5KW mod-sine (generally these are more like a mod-square wave, very few companies make multi step inverters) trying to power a large 5KVA power transformer as you linked to, will end badly for the inverter, the transformer will not be harmed. The auto-transformer is designed to adapt 120-240 split phase, but sine wave is going to be required.

john p · December 2011

Re: converting modified sinewave to signwave

If you have a Victron inverter it will work just fine with a transformer.
They are about the toughest bestest inverters made.
A 1000 w Victron will run motors that most other 2000w inverters struggling to start

icarus · December 2011

Re: converting modified sinewave to signwave

Why don't you just bite the bullet, and buy the proper inverter now, rather than monkeying around with a rather inelegant solution? The efficiency loses alone would justify going with the proper hardware IMHO.

I don't recall what you are going to power with this inverter, but going with a TSW inverter of the proper size is the best long term solution.

Tony

WillWinston · December 2011

Re: converting modified sinewave to signwave

mike90045 wrote: »

Can you give us a link to the inverter you have/are considering ?

Before you hook it up, be sure to have a spare can of this handy:

My belief is that the inverter will not like the large load presented by the transformer, and will release it's "Magic Smoke" when you try to connect it. A large inverter can easily power a small transformer, but I suspect a 5KW mod-sine (generally these are more like a mod-square wave, very few companies make multi step inverters) trying to power a large 5KVA power transformer as you linked to, will end badly for the inverter, the transformer will not be harmed. The auto-transformer is designed to adapt 120-240 split phase, but sine wave is going to be required.

I love the Lucas pic

Somewhere I have a pic of a T shirt that says

"If Lucas made firearms, wars wouldn't start just like my Brit bike"

System2 · December 2011

Re: converting 220v to 110220 split phase using a transformer

Hi guys,
Thank you for all your inputs, The inverter I bought is a "Power Express PE -5000W-24-220" and the reason i ordered such a beast was, I bought a Generac 7kw propane Generator which comes with a 50 amp transfer switch which is designed to hook up to a hydro line voltages.
So having Hydro I thought I could substitute the hydro with solar,wind battery and inverter system and when the battery bank gets low it would automatically switch to the Generator. So that is why I am in this delema.
More thoughts please.
Ron

mike95490 · December 2011

Re: converting 220v to 110220 split phase using a transformer

Power Express PE -5000W-24-220 - made in the same factory as Coleman but of a higher quality. ....

Fire, Ready, Aim.

Are you still within a return period to be able to get your $ back ??

converting modified sinewave to signwave

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