| Title: | DEChub/HUBwatch/PROBEwatch CONFERENCE |
| Notice: | Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7 |
| Moderator: | NETCAD::COLELLA DT |
| Created: | Wed Nov 13 1991 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 4455 |
| Total number of notes: | 16761 |
I was discussing our dual AC power solution with a DEChub 900 customer
and the customer told me that he thought our solution would introduce a
single point of failure in the power system. He would like to see the
ability to have some of the power supplies supplied by one AC feed and
the remaining power supplies supplied by the other AC feed (I think
some of our competitors have this feature).
Can someone comment on the following:
1. What is the MTBF for our dual AC system ?
2. What are the advantages/disadvantages of our dual AC solution
compared to what other vendors have ?
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 2025.1 | Some answers | NETCAD::SOHA | Thu Mar 09 1995 16:10 | 30 | |
Product Manager is Deb Flint, DELNI::FLINT
Some answers:
MTBF - @ 25 degrees C, > 3 million hours
@ 50 degrees C, > 1 million hours
So, MTBF should not be a concern, remember people have been designing
and making reliable relays for many many years, just for this
application.
As for your dual AC's into different P/S, I'm at a lost to understand
the benefit of this approach.
Assume two power supplies, P/S_1 and P/S_2, in a system.
With the dual line cord box: if AC-1 fails, the relays will switch to
AC-2 quick enough to keep the failure transparent to the system
(ie, ride-though of the power system > switching time). If AC-2
fails, the system does not switch and keeps AC-1 as the source.
With seperate AC lines: if AC-1 fails, then P/S_1 is out and the
system capacity, in terms of power, is reduced by half.
Hope this helps,
Mike S.
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| 2025.2 | Two Power Cord Option Needed! | DPDMAI::WISEE | Pobodys Nerfect | Thu Mar 09 1995 18:32 | 35 |
re -.1
What happens if you have the DEChub900 plugged into a NoBreak
power source and have N+1 for power supplies and the cable installer
or cleaning peson hits the power cord and it falls out of the DEChub?
Can't happen? Has happened to my customer on 4 occasions!
1. Cable installer pulling wire for the UTP patch field under the hub
Unplugged the rackmounted DEChub 900's ONLY power cord.
2. Rack mounted DEChub900 is in the Mechanical room and the rack is
bolted to the floor on the 12th floor. Elevator winch room next
door. The vibration caused toe ONLY AC power connection (mounted on
bottom of the hub with no cord lock of any type) to vibraate out
the socket.
3. Repeat Item # 2. This rack provides conectivity for and accounting
department. When did it do it? 3 PM on the last day of the
quarter!
4. Hub that is in a reworked 7-11 store is located in small equipment
room. Two dulpex plugs are located side by side. the back one is the
Cofffee pot and space heater. the front one is from a NoBreak plug
to the DEChub900. Nuf Said
Items 1, 2 and 3 were fixed by cable ties.
Item 4 was fixed by a device locking the plug into the outlet.
The need is there for TWO AC cords into the DEChub 900! If you want to
truly stat that their is no Single point of failure it is a MUST!
Efw
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| 2025.3 | SLINK::HOOD | This is my new personal name for Notes | Thu Mar 09 1995 18:42 | 1 | |
There is a two-ac-cord-into-the-DEChub option. | |||||
| 2025.4 | Dual power cord switch = H7661 | NAC::FORREST | Tue Mar 14 1995 13:59 | 4 | |
The Powerswitch option is H7661; it allows two power cords; if one
cord or power source fails, it switches over to the other power
source quick enough to keep the hub running.
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