How to change a 220vac single phase out put to a 220 split phase

Re: How to change a 220vac single phase out put to a 220 split phase

Lapeart wrote: »

I have a inverter with has a 220 single output but my house uses 220 split phase

You can get a transformer which will do this. The primary will be 240V and the secondary will be 240 with a center tap to provide 120/240 single phase three wire (not counting safety ground). In some cases, if neither side of the inverter output is grounded, you can use an autotransformer to reduce the cost. I believe that Outback, among others, offers such a transformer and it is expensive but very rugged.

Re: How to change a 220vac single phase out put to a 220 split phase

BB. wrote: »

And if you have 50 Hz inverter, you have to find a 50 Hz transformer (or derate your 60 Hz transformer).

If the transformer is limited by core saturation, you will have to reduce the input voltage to use 50 Hz, not just reduce the available power handling capacity.

A 240V 60Hz transformer cannot in general be used with 240V 50Hz. But it can be used with 200V 50Hz.

Re: How to change a 220vac single phase out put to a 220 split phase

Cariboocoot wrote: »

Of course the 50 Hz Voltage 'standard' is 230 and quite often lower (as per the 220 rating the OP used).

In reality you can indeed use a 240 VAC 60 Hz transformer with 230 VAC 50 Hz. It's not very efficient and the power rating must be lowered as Bill said. You will lose not only the 4-5% the transformer consumes but an additional 12% minimum in power capacity. Most people will never notice this on account of not running near the peak of the transformer's capacity. That helps a lot.

At 50Hz instead of 60Hz, the magnetizing current, and therefore the peak magnetic field, in the transformer core will be 6/5, 120%, of the current the transformer was designed for. The extra magnetizing current will cause greater I²R losses than designed. This will produce higher than normal zero load losses and will reduce the total current capacity and therefore the total load power capability of the transformer. All of this supports your point.

But a separate issue the 20% greater magnetic field can put the transformer at or beyond the saturation flux of the iron core. If this happens, the current can run to six or more times the design current because the inductance of an air coil is much lower than the inductance of an iron cored coil. It is this non-linear and very large current that I am concerned about.
The effect on the core would be the same as running the transformer with 290V 60Hz on the primary instead of 240V 60Hz. Not many transformers are designed that conservatively and I would not risk it without checking with the manufacturer of the transformer in question.

(The saturation of a transformer is related to the V/f ratio of the applied voltage. Check this out on the Mike Holt Forum if you are not convinced.)

Re: How to change a 220vac single phase out put to a 220 split phase

Cariboocoot wrote: »

In the real world it works for exactly the reasons I mentioned.

It just isn't great.

All that I am saying is that it may work for all of the transformers that you have tried, but that does not mean it will work for all transformers. And if it does not work, the consequences for the transformer will be catastrophic.

Re: How to change a 220vac single phase out put to a 220 split phase

Cariboocoot wrote: »

Don't buy junk.
Know what you are buying.
Problem solved.

Always buy 130V light bulbs, because the line voltage may go above 120V sometimes.
Different problem solved.