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18
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7.0
Physical/electrical specifications
7.1
AC power requirements: None
7.2
DC Power requirements
The voltage and current requirements for a single drive are shown in the following table. Values indicated
apply at the drive power connector.
Voltage
Regulation [4][2]
Average Idle Current [1]
Maximum Starting Current (Peak) [5][6] 0.75 A
Delayed Motor Start (Max) [3] [5]
Operating Current [6]
[1] Measured with average reading DC ammeter. Instantaneous +12 V currentpeaks will exceed these val-
ues.
[2] A droop of up to -10% is permissible during the T2 portion of the +12 V power up (see Figure 7.2.2-1).
[3] This condition occurs when the Motor Start Option is enabled and the drive has not yet received a Start
Motor command.
[4] See Section 7.2.1 "Conducted Noise Immunity".
[5] Peaks of 0.90 A (nominal) on +12 V will occur for no more than 100 ms total during the first 250 ms after
power is applied.
[6] Instantaneous peaks in excess of these values and less than 5 msec. in duration are allowed.
General Notes from Table 7.2-1:
1. At power-up, the motor current regulator limits the 12 volt current to a peak value of less than 2.0 am-
peres, although instantaneous peaks may exceed this value. These peaks should measure 5 msec.
duration or less.
2. Operating condition is defined as Random Seek Reads of 64 blocks.
3. Minimum current loading for each supply voltage is not less than 30% of the maximum operating current
shown.
4. The +5 and +12 volt supplies shall employ separate ground returns.
5. Where power is provided to multiple drives from a common supply, careful consideration for individual
drive power requirements should be noted. Where multiple units are powered on simultaneously, the
peak starting current must be available to each device.
Product Manual - Hawk 4 Family (Wide) SCSI-2 (Volume 1), Rev. E
Table 7.2-1. DC power requirements
Wide
Single Ended
+5 V
+5%
0.37 A
0.56 A
Typ. [1]
0.90 A
Max. [1]
0.94 A
Max. (Peak)
1.57 A
Wide
Differential
+12 V
+5 V
+5%
+5%
0.55 A
0.51 A
2.61 A [2]
0.85 A
0.22 A
0.56 A
0.65 A
1.1 A
1.0 A
1.25 A
2.2 A
1.57 A
+12 V
+5%
0.55 A
2.61 A [2]
0.22 A
0.65 A
1.0 A
2.2 A
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