OK......CLASS IS NOW IN SESSION!!
Think of a bucket full of water. The amount of water in the bucket is the WATTAGE.
Think of 3 holes in the bottom of the bucket: 2 holes 0.1" in diameter and one 1" in diameter.
The 2 small holes are the +15V and -15V feeds, the large hole is the +5V feed.
We observe the following:
a) if we plug up the +5V hole, the same amount of water still comes out the other 2 holes
b) if we plug up the 2 small holes, the same amount of water comes out the big hole
In other words, the 3 ∗currents∗ (the water coming out) are independent of ∗each other∗ BUT (and here is the big but), the OVERALL CAPACITY is the size of the bucket (the power supply wattage).
However......the Power One has ∗set limits∗ on the WATTAGE drawn out of EACH of the 3 supplies. If that individual is exceeded, a circuit then 'shuts down' that output. There is no 'current stealing' :(
If you "max out" say the +5V side by plugging in 8 uSeqs, you can still pull ADDITIONAL wattage out of the +-15V side. I can't say exactly how much +-15V current the new modules draw. Overall, the answer is "about 15ma".
Does this help??!?
Paul S.