Elite 47 Product Manual, Rev. A
23
Note.
All times and currents are typical. See Table 1 for maximum current requirements.
6.3
Power dissipation
ST446452W
Typical operating random read power dissipation is 24 watts (82 BTUs per hour) of DC power average at nom-
inal voltages.
6.4
Environmental limits
Temperature and humidity values experienced by the drive must be such that condensation does not occur on
any drive part. Altitude and atmospheric pressure specifications are referenced to a standard day at 58.7°F
(14.8°C). Maximum wet bulb temperature is 82°F (28°C).
6.4.1
Temperature
a. Operating
The drive meets all specifications over a 41°F to 122°F (5°C to 50°C) drive ambient temperature range with
a maximum gradient of 36°F (20°C) per hour. The enclosure for the drive should be designed such that the
temperatures at the locations specified in Table 2 are not exceeded. Air flow may be needed to achieve
these temperature values. Operation at case temperatures above these values may adversely affect the
drives ability to meet specifications.
The MTBF specification for the drive is based on operating at an ambient temperature of 86°F (30°C).
Occasional excursions to drive ambient temperatures of 122°F (50°C) or 41°F (5°C) may occur without
impact to specified MTBF. To achieve the specified MTBF, the enclosure for the drive should be designed
such that the temperature values of Table 2 are not exceeded. Air flow may be needed to achieve these
temperatures. See Section 8.3.1. Continual or sustained operation at case temperatures above these val-
ues may degrade MTBF.
To confirm that the required cooling for the drive electronics and HDA is provided, place the drive in its final
mechanical configuration, perform random write/read operations and, after the temperatures stabilize, mea-
sure the case temperature of the components listed on the next several pages.
Operation of the drive at the maximum case temperature is intended for short time periods only. Continuous
operation at the elevated temperatures will reduce product reliability.
T3 -
The spindle is up to speed and the head-arm restraint is unlocked.
T4 -
Heads move from the landing zone to the data area.
T5 -
The adaptive calibration sequence is performed.
T6 -
Calibration is complete and the drive is ready for reading and writing.