JAMES IRVINE

I was wondering if anyone can help me to understand a bit about this transformer http://www.farnell.com/datasheets/38796.pdf it is type 24/6 in the list it has a 0-115v primary rating and a 0-6v secondary rating at 12VA. This is the transformer I have been supplied with to complete my project on the DC to AC inverter which requires a specified 240volts output and I calculated that the current would be 24A but maybe I'm wrong about that. see for yourself http://www.interq.or.jp/japan/se-inoue/e_ckt30_1.htm

The question is can I use the secondary as the primary and convert 12 volts into 230 volts at the output. Also the pdf doesnt explain what the four pin connections are for can anyone explain? I'm thinking that this is configured as two transformers in one in which case two pins are live and two are ground is this correct? But which is which?

ericgibbs

hi,
Look at this drawing for the connections.

The transformer has two primary windings so that it can be used on 120Vac or 240Vac mains.

On 240Vac the two 120V are connected in series, on 120vac mains the two 120V are connected in parallel.

The secondaries are two 6Vac at 2Amp. When connected in series give 12Vac.

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JAMES IRVINE

so do I connect together the two inner pins with a thick bit of copper to make it be in series and use the two outer pins for live and ground.

ericgibbs

hi,
You only need to connect the two 6Vac windings with 20SWG wire, the two 120Vac just a short length of insulated 24SWG or 20SWG.
There will only be 100ma flowing out of the 240Vac winding.

The 240Vac output side is equivalent to Line and Neutral NOT Ground.

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JAMES IRVINE

Thanks eric do you know what SWG rating I would need for carrying the 24amps from the battery to the mosfets.
Also I've been thinking about it which side is neutral and have come to the conclusion that it's whichever side I chose it to be am I right.

audioguru

The tiny transformer has a max allowed output of only 24W.
The transformer in the project is 5 times the power and 5 times the size.

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ericgibbs

hi,
There is no way that the circuit should draw 24Amp.!

It should be 2 Amps 'tops'. Its only a 24VA rated transformer

Choose is right for the L and N.

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Hero999

Just make sure the fuse and power switch is on the live and not the neutral.

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JAMES IRVINE

What about the original circuit drawing 10amps so there will be less current drawn in the British circuit I don't know I thought I had that correct but I was having doubts. http://www.interq.or.jp/japan/se-inoue/e_ckt30_1.htm

ericgibbs

hi,
To draw 10Amps would mean that its a 120Va rated transformer with a FULL load on the secondary of about 0.5Amps.

If the load current in the transformer secondary was only say 0.25A [HALF load] then the primary current of the 120Va transformer would be about 5 Amps.

Assuming 100% efficiency.

Do you follow.?

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Eric
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audioguru

The original project uses a big 12v/10A transformer.
Your little transformer has a max allowed current of only 2A at 12V.

The original circuit has a max power output of 120W at whatever voltage is the transformer. Its max current is 10A from the 12V battery.

Your little transformer reduces the max allowed current from your 12V battery to 2A which is a power of only 24W at the output.

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