The Input Rating and also Three Phase Power Supply

Dears,

I have a loaded pistol. Not sure what kind it is.

How do I know which end the bullets come out?

You have some good information in your post:

• You're telling us what the load requires. (30/60V DC 120A)
• You're telling us what the local power main is (415V 3P)
• You're providing us with the tech sheets on the power supplies you're looking at.

Here is some information you may not have realized:

• 30/60V DC at 120 Amps is 3.6Kw/7.4Kw of power than is more power than an untrained person should be playing with, by a few orders of magnitude.
• You are not telling us which country the project is being done in. Local electrical codes vary, and what may be allowed in Sampledorf may not be allowed in Ollieandstan.
• You are telling us 'between the lines' that this is a new construction, not a case of replacing a damaged/defective part. (If it were a matter of replacing what is broken, you simply make sure the new matches the rating of the old) You are also telling us that this project is not well planned out, since the designers would have determined the right component based on the load and the local rules and regulations on industry.
• You are also telling us 'between the lines' that you may not have all the skills required to fully understand the project, as the fuse selection is rather simple. If the fuse is on the load side of the PSU it would need to be a 120 Amp fuse, id the fuse is on the supply side it would need to be, as a rough guess (60V x 120A = 7.4Kw || 7.4Kw / 415 V = 17.25A give or take) 18 Amps.
  

And all that adds up to one thing:

• You are asking a semi-anonymous group of people for help on a serious safety issue that will have severe liability consequences should something go wrong.
  

I would strongly recommend that you consult with a local Electrical Engineer for assistance, he could look at the whole project and give better advice than we can from here.