kva

You'd better calculate Kcal for that on the primary. S.M.

What? (Volts)*(Amps)/1000

KVA is a component of an AC system and does not exist on a DC system. So you can not calculate it. For DC systems, straight kilo watts applies.

I think you need to clarify your question. Are you trying to design a transformer or buy one?

Generally, to buy (or design) a transformer, you first need to determine the voltage on the primary and secondary, and then also determine whether you need single phase or 3 phase power. (If three phase, you will need to consider whether each side should be delta or wye connected. This depends on things like the grounding scheme you plan to use.)

Then you need to look at the loads you need to serve (considering an allowance for future expansion and such). That determines the kva. If your load is too big, you may need to divide it and serve it with multiple transformers.

The designers of a transformer design the wire size, core, and such, to handle approximately kva on the primary and the secondary.

For DC, you can calculate KW, which is essentially the same as kva for DC as the power factor for DC is 1.

Hi all, I have bought my own transformer 240vac 24-0-24vdc for my own use, and wanted to install mcb for protection on both pri. & sec. Please advise.

How many kva (or amps, on the secondary)?

Too many kvas

what is the rated secondary current of the transformer ?

The protection is needed to protect the wiring, not the transformer!

Transformer 240vac 24-0-24vdc