transformer load calculations

[doninphx]

I would like to find an easy to build a spread sheet to give me KVA required to size a transformer. Both single phase and three phase.
I have panels with multiple devices in them and the current and voltage of each device.
I am using the transformere for Isolation only...so I will be using a 120/208 to 120/208 transformer...any sugestios...
please reply to --- thanks...
I am a jiw out of #640 phoenix az...

rbalex Edit - I have removed the personal email address as is our policy; however, anyone may contact doninphx through the PM system.

 

[templdl]

Do you know what the actual anticipated load is going to be?
Do you know what that addition anticipated capacity would be need for future growth?
Work that up and you should be able to select a transformer that would be suitably sized for the application.
Other considerations may be k factor, a temperature rise other than the standard 150degC as well as ambient temperature. Ambient temperature normally isnot a probem if it is 30degC, 40degC max. If it gets above that then you have to throw that into the pot when sizing the transformer. However, let the experts do that but you must provide them with the information.

 

[robbietan]

utilities here just get the biggest loads the facility will have and add the usual loads for lighting and voila!, a transformer is sized. taken note was the inrush currents if ALL the motors are started at the same time