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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
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

1449.0. "DH900 & PWR SUPPLIES" by SNOC01::KOOLE () Tue Sep 20 1994 02:29

    Hi,
    
    	a customer who is buying a DH900 wants to know .. if a power supply
    shorts out , will it bring down the other power supplies and therefore
    the hub ?
    
    If not, how is this achieved ?
    
    	thanks
    
    	John
    
    ps I know this is a bizzare question but the customer is placing a lot
    of importance on this issue..
T.RTitleUserPersonal
Name		DateLines
1449.1OR'ing DiodesDELNI::MACARTHURTue Sep 20 1994 09:3219
    John,
    
        The DH900 Power Supplies were designed with OR'ing diodes on the
    DC outputs. This diode on each output effectively blocks the shorted
    supply from bringing down the other supplies that are plugged into the
    Hub. The only way a failed supply could take down others in a HUB is if
    the OR'ing diode in a supply failed. This alone will not create a
    problem, but if other components in that same supply were to fail and
    create a short circuit across the output, then this could take down 
    the entire HUB. This is obviously a highly unlikely situation. The
    OR'ing diodes that we use in the DH900 supplies are overdesigned for 
    the application so that this kind of event shouldn't occur.
    
        Hope this answers your questions. If not, feel free to contact me
    and I'll provide you with further details.
    
    Bob MacArthur
    Power System Engineer for the DH900
1449.2good info ( good design !)SNOC01::KOOLETue Sep 20 1994 18:206
     Bob,
    
    	thanks for the data. This sort of detail is great (and helps to
    close business :-) ).
    
    	john