Archive of the former Yahoo!Groups mailing list: MOTM

Hi -

I've inherited responsibility for maintaining a >40 module MOTM.

Paul advised me to ditch our Power One HDCC 150W (3A) in favor of two
CP131As:

5VDC@8A w/OVP
+/-15VDC@1.5A
Max Current/Fuse Rating 3A@120V

I was hoping to get some guidance and reality checks before I get
started . . . .

First, fuses: I see that there is a 4A fuse in the AC input connector
drawer. I plan to replace it with a 1.5 Amp fuse and do the same
thing with another AC input connector for our second power supply.
Does this sound right? Are these the only fuses necessary?

Second, wire gauge: I understand that 12 gauge wire should be used to
bring power from the supply to the distribution boards and to daisy
chain other distribution boards. However, I notice that 18 gauge wire
is being used to connect the AC input connector to the power switch
and the power switch to the transformer on the power supply. I would
have thought that 12 gauge wire would have been required there, as
well. Is it not?

Third, I understood from Paul that it would be OK to daisy chain the
distribution boards as long as I use 12 gauge wire. We're talking
990, 960, and 900 on one supply, and a 960 & 900 on the other. From
what I've been reading it seems it might be better to use barrier
strips. Is this true? I don't really understand how this would work
(I've never dealt with barrier strips) -- Is it sort of like a mult
and works with jumpers?

Last, just to double check: I wire to the terminals on the power
supply that say +12V, -12V, +-RTN (for analog GND), 5V.RTN (for
digital GND), and either of the +5V terminals. I ignore all the rest,
which have 'S' in front of them (for remote sensing?).

Thank you so much for any advice you can offer.

- James