Sun Microsystems StorageTek StreamLine SL8500, System Assurance Manual

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E24254-01 Chapter 1 Introduction 13
Introduction
Load Sharing DC Power Supplies
The SL8500 has three DC power grids that supplies 48 VDC to components
throughout the library:
• The tape drive power grid supports up to 64 tape drives.
• The robot power grid powers the HandBots and the pass-thru ports.
• The front frame power grid supplies 48 VDC power to the cartridge access
ports, elevators, turntables, and the service safety door.
Table 6. Load Sharing Power Supplies
Power Supply Type Quantity Configuration
1
N+1 2N
16 2 + 1 = 3 2 + 2 = 4
24 3 + 1 = 4 3 + 3 = 6
32 4 + 1 = 5 4 + 4 = 8
40 5 + 1 = 6 5 + 5 = 10
48 6 + 1 = 7 6 + 6 = 12
56 7 + 1 = 8 7 + 7 = 14
64 8 + 1 = 9 8+ 8 = 16
8 tape drives 4 tape drives
4 2 + 1 = 3 2 + 2 = 4
8 4 + 1 = 5 4 + 4 = 8
2 HandBots 1 HandBot
1 + 1 = 2 1 + 1 = 2
1 + 1 = 2 2 + 2 = 4
The DC power grids use load sharing power supplies . Load sharing allows the
output voltage of one supply to be monitored and adjusted by other supplies
on the bus.
In effect, each independent output voltage is adjusted so that all of the
independent output voltages are the same to evenly distribute the load so if
one output fails or is shorted, it will not bring down the bus.
Table 6 explains the quantity of load sharing power supplies required for each
power configuration and the number of components they power.
Tape drives—from one to:
This allows one supply for every:
Robotics
This allows one supply for every:
Front frame components
Electronics control module
2
1
Requires the 2N power configuration and matching DC power feature codes.
2
The electronic control module (ECM) power supplies are AC to DC converters and
different from the load sharing power supplies used by the HandBots and tape drives.