I normally use the "sh environment all" command to find that info (I believe that is included in the output of the sh tech as well but you have to sort through everything to find it):
U03751301#sh env all
Arbiter type 1, backplane type 7513 (id 2)
Power supply #1 is 1200W AC (id 1), power supply #2 is 1200W AC (id 1)