Connecting a DC power supply to a DC power source
A Storwize® V3700 enclosure that is DC powered contains two DC power supply units (PSUs). Each unit must be connected to a suitable -48V DC power source. To provide redundancy in a power circuit failure, connect the two PSUs to different DC power sources.
Use the supplied cables to connect the DC PSUs to the power sources. Use only the IBM® supplied DC power cable (IBM part number 00AR087) to connect the unit to a DC power source.
Each PSU cable must be protected by a 20A circuit breaker. These instructions assume that the circuit breaker is separate from the DC power distribution unit. Refer to the DC power distribution unit documentation and the circuit breaker documentation for details. Follow the instructions that are given there for connecting the circuit breaker to the power distribution unit and for connecting the DC power cable to the circuit breaker.
One end of the cable ends in a plug that fits the DC PSU. At the other end of the cable, each individual wire ends with a 6 mm diameter ring terminal that is designed to fit an M6 stud. Provide adequate strain relief after you attach the ring terminals to the power source. Table 1 lists the wire colors.
Color | Function |
---|---|
Blue | Return |
Green / Yellow | Ground |
Brown | -48V |
The DC power cable is 4 m long. Connect it to the DC power source before you connect it to the PSU. The PSU does not have a power switch, so its outputs and the enclosure become live as soon as power is connected.
The supplied power must meet the input requirements that are listed in Table 2.
Requirement | Min | Max |
---|---|---|
Voltage (V DC) | -48 | -60 |
Instantaneous (V DC for < 1 second) | -36 | -75 |
Inrush current at initial turn on (-48V DC) | 34 A | |
Out of spec time before power off is signaled | 5 ms |
The connection to the DC power source must be made by trained service personnel. Ensure that the connection is made in accordance with all the requirements of the equipment that is being used.
The DC power cable must be totally contained in a single rack and must not extend outside the rack to another rack.
If it is necessary to replace the ring terminals with a different connector, choose a suitably sized and rated UL-listed connector that is appropriate for the wire gauge and available current. Install the ring terminals according to the instructions provided by the manufacturer.