Thanx for the help, how can i figure out what the power factor is?
Not easy, probably not important anyway. if it is a motor, it may say so on the nameplate, if it doesn't, assume .8 for making calculations. if it is a coil, there is not way to know, but it doesn't matter much anyway, just find out the inrush VA from the manufacturer.
And when im wiring the transformer i use L1 and L3, is this ok or should i be using differnt legs?
The convention is to use L1 and L2, but technically it doesn't matter. The only reason to follow that convention is for the convenience of someone in the future who would expect to find it there. In practice though, sometimes you need to balance loads, so it is acceptable to connect anywhere.
Also is there a rule of thumb on how much the inrush will be based off of the constant amps the unit pulls?
No. None whatsoever. It has to do with the iron in the coil, the winding design, the magnetic force it needs to exert etc. Every coil is going to be different. For that reason, manufacturers always make that information available to you. The web is great for that now.
And i can never tell what the amp rating for the coil is on the motor starter, so for example im using an AB 120v coiled 3phaze starter with 1 N/O contact part# 100C12D10.
Forget the coil's part number, that is just for ordering a replacement. Look in the AB catalog in the back of the contactor section for the "Technical Data", it will be there cross referenced to the part number of the starter or contactor. Here's an example if it is a "Buletin 509" starter; scroll down to the section that says "Coil Data"
A-B Bul 509 Technical data link
