Using DC Power

Caution - A qualified service person is required to make the DC power connection per NEC and CEC guidelines. A two-pole 20-amp circuit breaker is required between the DC power source and the array module for over-current and short-circuit protection. Before turning off any power switches on a DC-powered module, you must disconnect the two-pole 20-amp circuit breaker.

Caution - Electrical grounding hazard - This equipment is designed to permit the connection of the D.C. supply circuit to the earthing conductor at the equipment.

FIGURE B-1 shows the DC Power Connectors and DC Power Switch.

FIGURE B-1 DC Power Connectors and DC Power Switch.

Caution - Risk of electrical shock - This unit has more than one power source.
To remove all power from the unit, all DC MAINS must be disconnected by removing all power connectors (item 4 in Appendix FIGURE B-2) from the power supplies.

FIGURE B-2 DC Power Connector Cable and Source Wires

Site Preparation for DC Power

This section updates the Sun StorageTek 6140 Array Site Preparation Guide with information regarding site power and wiring, power requirements (-48 VDC), and power cord routing instructions for the Sun StorageTek 6140 array:

Site Wiring and Power

DC Power Input

DC Power Connector Cables and Source Wires

Site Wiring and Power

The Sun StorageTek 6140 array uses wide-ranging, redundant power supplies that automatically accommodate voltages to the AC power source or the optional -48-VDC power source.

The power supplies meet standard voltage requirements for both North American (USA and Canada) operation and worldwide (except USA and Canada) operation. The power supplies use standard industrial wiring with line-to-neutral or line-to-line power connections.

Note - Power for the optional -48-VDC power configuration is supplied by a centralized DC power plant instead of the AC power source in the cabinet. Refer to the associated manufacturer’s documentation for specific DC power source requirements.

Consider the following information when preparing the array’s installation site:

Protective ground - Site wiring must include a protective ground connection to the AC power source or the optional -48-VDC power source.

Note - Protective ground is also known as safety ground or chassis ground.

Circuit overloading

Power circuits and associated circuit breakers must provide sufficient power and overload protection. To prevent possible damage to the array, isolate their power source from large switching loads (such as air- conditioning motors, elevator motors, and factory loads).

Interruptions:

Input transient - 50 percent of the nominal voltage

Duration - One-half cycle

Frequency - Once every 10 seconds

Power failures - If a total power failure occurs, the array automatically performs a power-on recovery sequence without operator intervention after power is restored.

DC Power Input

The DC power source must provide the correct voltage, current, and frequency specified on the array nameplate label and the serial number label.

The DC power limits within which the Sun StorageTek 6140 array can run without interruption include the following:

Nominal voltage

Low range: -36 VDC

High range: -72 VDC

Operating current: 15.8 A maximum

DC Power Connector Cables and Source Wires

The Sun StorageTek 6140 array is shipped with -48-VDC power connector cables if the DC power option is ordered. The power connector cable plugs into the DC power connector on the back of the array (Figure 6-3 on page 6-3). The three source wires on the other end of the power connector cable connect the array to centralized DC power plant equipment, typically through a bus bar above the cabinet. A qualified service person is required to make this DC power connection. DC Power Connector Cable and Source Wires shows the DC connector cable and the source wires.

Two (or optionally, four) DC power connector cables are provided with each array. There are two DC power connectors on the back of each array’s two DC power supplies if additional redundancy is required.

Note - It is not mandatory that the second DC power connection on the array’s DC power supplies be connected. The second DC power connection is provided for additional redundancy only and may be connected to a second DC power bus.

Additional DC Specifications

The following are specifications for DC power for a fully populated controller or expansion module:

Heat Output: 445 Watts (1519 BTU/Hr) using DC Power Source (NEBS)

Safety and Emissions: EN 300 386 (NEBS)

Installation Notes for DC Power

The sections that follow update the Sun StorageTek 6140 Array Hardware Installation Guide for DC power.

Ship Kit Changes

DC Power LEDS

DC Power Caution When Link Rate Switching

Connecting Power Cables

Turning Off the DC Power During an Emergency

DC Power Caution When Link Rate Switching

Relocation Cautions

Ship Kit Changes

If the DC power option is ordered, two DC power connector cables are provided with each controller tray for connection to centralized DC power plant equipment.

Two additional DC power connector cables should be ordered if additional redundancy is required.

DC Power LEDS

The following table lists the LEDs for DC power.

TABLE B-1 Lights on the Array Module
Light	Symbol	Location (CRUs)	Function
DC Power (Optional)		Power-fan Note Light is directly above or below DC power switch and DC power connector	Indicates the power supply is receiving DC input power
Direct Current (DC) Enabled		Power-fan	Indicates the power supply is outputting DC power

DC Power Caution When Link Rate Switching

Caution - Change the Link Rate switch only when there is no power applied to the controller tray. The link rate setting is read only at power-on. Before turning off any power switches on a DC-powered tray, you must disconnect the two-pole 20-amp circuit breaker.

Connecting Power Cables

To use the DC power option (-48-VDC) to power the array module, review the following points.

Ensure that you use a separate power source for each optional DC power connector on the array module. Connecting to independent power sources maintains power redundancy.

It is not mandatory that the second DC power connection on each of the array module’s DC power-fan CRUs be connected. The second DC power connection is for additional redundancy only and may be connected to a second DC power bus.

Caution - A qualified service person is required to make the DC power connection per NEC and CEC guidelines. A two-pole 20-amp circuit breaker is required between the DC power source and the array module for over-current and short-circuit protection. Before turning off any power switches on a DC-powered module, you must disconnect the two-pole 20-amp circuit breaker.

Caution - Ensure that you do not turn on power to the array module or the connected drive modules until this guide instructs you to do so. For the proper procedure for turning on the power, see “Connecting Power Cables.”

Caution - Electrical grounding hazard - This equipment is designed to permit the connection of the D.C. supply circuit to the earthing conductor at the equipment.

Connecting the Cables

1. Disconnect the two-pole 20-amp DC circuit breaker for the storage array.

2. Ensure that all DC power switches on the DC-powered array module and all DC power switches on any connected, DC-powered drive modules are turned off.

3. Connect the DC power connector cable to the DC power connector on the back of the array module.

Caution - The three source wires on the DC power connector cable (-48 VDC) connect the array module to centralized DC power plant equipment, typically through a bus bar located above the cabinet.

Note - It is not mandatory that the second DC power connection on each of the array module’s DC power-fan CRUs be connected. The second DC power connection is for additional redundancy only and may be connected to a second DC power bus.

4. A qualified service person is required to make the DC power connection per NEC and CEC guidelines. A two-pole 20-amp circuit breaker is required between the DC power source and DC-powered modules for over-current and short-circuit protection. Connect the DC power source wires on the other end of the DC power connector cable to the centralized DC power plant equipment as follows (see DC Power Connector Cable and Source Wires).

a. Connect the brown -48-VDC supply wire to the negative terminal.

b. Connect the blue return wire to the positive terminal.

c. Connect the green/yellow ground wire to the ground terminal.

5. If applicable, connect a DC power cable to each DC-powered drive module in the storage array.

Turning Off the DC Power During an Emergency

Caution - Potential loss of data - An emergency shutdown of the storage array might not allow the server to complete its I/O to the storage array.

Note - Trays in storage arrays can be connected to either the standard AC power supply or the optional DC power supply (-48 VDC).

Note - Before turning off the power switches on a DC-powered tray you must disconnect the two-pole 20-amp circuit breaker.

Relocation Cautions

Use the following guidelines when relocating trays or drives from one storage array to another.

Caution - Potential data loss - Moving a array or array components that are configured as part of a volume group can result in data loss. To prevent data loss, always consult a Customer Support representative before relocating configured drives, controller trays or expansion trays.

Note - Trays in arrays can be connected to the DC power supply (-48 VDC). Before turning off any power switches on a DC-powered tray, you must disconnect the two-pole 20-amp circuit breaker.

Do not move controller trays or expansion trays that are part of a volume group configuration. If you must move array components, contact a Customer Support representative for procedures. A Customer Support representative might direct you to complete several tasks prior to undertaking the relocation. These tasks might include:

Creating, saving, and printing an array profile of each storage array that is affected by the relocation of a drive or tray.

Performing a complete backup of all data on the drives that you intend to move.

Verifying that the volume group and each of its associated volumes on the affected array have an Optimal status.

Determining the location and status of any global hot spares associated with the affected storage array.