VA rating of 50Hz transformer

[eem2am]

We need to replace our 230VAC, 50Hz transformer based PSU with a switch mode power supply.

I am not exactly sure what is the maximum power rating of the existing 50Hz transformer based PSU.
-We have a spec sheet for it, but no VA rating is given.

So, the 50Hz transformer is custom built and has a spec sheet saying
“loaded voltage = 25V when loading is 65 Ohms”

….from this, should I presume that the transformer is rated at 9.6W?

Here are more details of our 50Hz transformer:-
Vin=230VAC
Chassis Mounted
V(isol) = 4200V (PRI to SEC)
Laminated core is of external dimension 26mm by 53mm by 45mm

Would you say that this is a 10VA transformer?

 

[Prototyp_V1.0]

This is a very small transformer, so yes I guess 10 VA might be maximum ratings over time. You should test it with a 10W resistor or other device that draws current an just tell if the transformer gets hot after a minute or so.

 

[srizbf]

your calculation is correct. 9.6va rated .
and 10va best guess.