#### prasannarao

##### Newbie level 3

**transformer secondary current calculation**

Hello,

I am curious to know if we can estimate the maximum possible secondary current for a transformer with some given VA rating. This can be useful in estimating the approximate time for the rectifier-filter circuit to charge-up to the peak rated voltage under no-load condition. To the best of my knowledge it is a function of primary and secondary coil resistances and also to an extent their leakage reactances.

Note that the reservoir capacitor in the filter becomes a near short circuit at startup resulting in a very large secondary current.

So I am interested in finding a way to manually measure this maximum possible peak current, or even better, roughly estimate it for a transformer with some given specifications.

Thanks,

Prasanna