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2 power supply requirements – FUJITSU MAP3735FC User Manual

Page 59

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4.2 Power Supply Requirements

C141-E163

4-7

4.2

Power Supply Requirements

(1)

Allowable input voltage and current

The power supply input voltage measured at the power supply connector pin of the IDD (receiving
end) must satisfy the requirement given in Subsection 2.1.3. (For other requirements, see Items (4)
below.)

(2)

Current waveform (reference)

Figure 4.7 shows the waveform of +12 VDC.

MAP3147FC

C

u

rrent

(500m

A

/di

v

)

MAP3735FC

C

u

rrent

(500m

A

/di

v

)

Time (2 sec/div)

Time (2 sec/div)

Figure 4.7

Current waveform (+12 VDC)

(3)

Power on/off sequence

The order of the power on/off sequence of +5 VDC and +12 VDC, supplied to the IDD, does not
matter.

(4)

Sequential starting of spindle motors

After power is turned on to the IDD, a large amount of current flows in the +12 VDC line when the
spindle motor rotation starts. Therefore, if more than one IDD is used, the spindle motors should be
started sequentially using one of the following procedures to prevent overload of the power supply
unit.

a) Issue START/STOP commands at more than 12-second intervals to start the spindle motors. For

details of this command specification, refer to Fibre Channel Interface Specifications.

b) Turn on the +12 VDC power in the power supply unit at more than 12-second intervals to start

the spindle motors sequentially.

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