Step down transformer Japan to Australia

So I have just brought my old rice cooker back from Japan which has the following power rating.
100V 1240W
50/60Hz.
�d���t���[�Y 15A

I brought back a �gPower Voltage Converter�h with the following specs.
AC Input: 100-260V 40-60Hz
AC output: 100V - 130V
Maximum power: 1875W

I plugged a usb charger in to check, and it worked no problem. Then I plugged the rice cooker in and it blew the house fuse instantly.

By my calculation the rice cooker uses 12.4A
And so the 240V input would be only using 5.2A
It seems to be well within what we can use..
Does anyone have any ideas? Or am I completely making a mistake here?

Rice cookers use significant amounts of energy. My mini rice cooker uses 1500W while larger ones use more. I have a step-down transformer for this which weighs over 7 kg and can handle up to 1800W

Thanks for the reply.

Yeh as I thought, the 3000yen stepdown transformer I bought which has 1800w rating written on it only weighs about a few hundred grams. It doesn�ft quite make sense, it�fs rating.

I should have been more explicit.

Just confirming that I am a science teacher. It is correct that your step down transformer probably can handle 1800W at a constant wattage for a specific amount of time.

It is correct that the step down transformer lowers the voltage by increasing the current. However, large changes in wattage by things such as rice cookers (or hair dryers) are pretty notorious for causing major problems in other countries. This includes with $35 AUD step down transformers.

I purchased a VERY HEAVY DUTY step down transformer to limit the possibility of this occurring.

Feel free to read into this (or ignore this) what you will...

Cheaper to by a rice cooker with a 220-240V rating that deal with step down transformers. You are looking at a few hundred AUD for a good one for high load devices. Pretty sure a 3000JPY/$30AUD isn't gonna cur it. No matter what it says on the box.

And it probably should weigh about 10-15 kilograms.

I've bought a stepdown transformer from Jaycar and and another from an online shop based in Melbourne, they were around the $75-150 range depending on wattage. The big one (2kW from memy) runs a bread maker and rice cooker at the same time, however we are careful not to start both at the same time (e.g. rice cooker needs to be maintaining temp, not heating up when bread maker is turned on).

As mentioned above in the thread they weigh a fair bit as they contain an iron core transformer. The little plastic step down units are only really good for lightly loaded accessories using switch-mode power supplies (e.g. console power pack).

This is the store I bought our larger unit from, much better priced than Jaycar.

https://www.wallcann.com.au/3000w-voltage-converter/?___store=default

Can you suggest me some best destinations of world for holidays.

https://www.merrchant.com/daily/3/all-inclusive-holidays/