Reasonable maximum exciting current 60Hz step up transformer
Your measured 2 A open-circuit current seems reasonable. You are measuring 24 VA, but the watts loss may be about 1/3 of that or 8 watts. You can assume that will be the iron loss and that it will not change with load. Once you load the transformer, you will see copper loss added to that. If you want to determine the efficiency of the transformer, you will need a wattmeter. If you search the internet, you should be able to find the procedure for performing open-circuit and short-circuit transformer tests and calculating copper losses.