USER RESPONSIBLE FOR VERIFYING VERSION AND COMPLETENESS
OEM FUNCTIONAL SPECIFICATION ULTRASTAR XP (DFHC) SSA MODELS 1.12/2.25 GB -1.0" HIGH
7.2.1 Drive Mounting Guidelines
The following guidelines ma y be helpful as drive mounting systems are being designed.
1. Mount the drive to its carrier/rack using the four extreme side holes to ensure that the drive's center of
gravity is as close as possible to the center of stiffness of the mounting.
2. Do not permit any metal-to-metal impacts or chattering between the carrier/rack and the drive o r
between the carrier/rack and anything else. Metal-to-metal impacts create complex shock waveforms
with short periods; such waveforms can excite high frequency modes of the components inside the drive.
3. The carrier/rack shoul dn ot allow the drivet o rotate in the plane of the disk and the carrier/rack itself
should be mounted so that it does not rota te in the plane of the disk when the drive is running. Even
though the drive uses a balanced rotatory actuator, its position can still be influenced by rotational accel-
eration.
4. Keep the rigid body resonances of the drive away from harmonics of the spindle speed. Consider not
only the drive as mounted on its carrier but also when the drive is mounted to a carrier a nd then the
carrier is mounted in a rack, the resonances of the drive in the entire system must be considered.
7200 RP M Harmonics: 120 hz, 240 hz, 360hz, 480 hz, .....
5. When the entire system/rack is vibration tested, the vibration amplitude of the drive as measured in all
axis should decrease significantly for frequencies above 300 hz.
6. Consider the use of plastics or rubber in the rack/carrier design. Unlike metal, these materials can
dampen vibration energy from other drives or fans located elsewhere in the rack.
7. Rather that creating a weak carrier/rack that flexes to fit the drive/carrier, hold t he mounting gap to
tighter tolerances. A flexible carrier/rack may contain resonances that cause operational vibration and/or
shock problems.
7.2.2 Output Vibration Limits
spindle imbalance 1.0 gram-millimeters maximum for C1x, C2x models
1.5 gram-millimeters maximum for C4x model
7.2.3 Operating Vibration
The vibration is applied in each of the three mutually perpendicular axis, one axis at a time. Referring to
Figure 24o n page 81, the x-axis is defined as a line normal to the front/rear faces, t he y-axis is defined as a
line normal to the left side/right side faces, and t he z-axis is normal to the x-y plane.
WARNING: The Ultrastar XP SSA drives are sensitive to rotary vibration. Mounting within using
systems should minimize the rotational input to the drive mounting points due to external vibration.
IBM will provide technical support to assist users to overcome problems due to vibration.
Random Vibration
For excitation in the x-direction a nd the y-direction, the drive meets the required throughput specifications
when subjected to vibration levels not exceeding the V4 vibration level defined below.
For excitation in the z-direction, the drive meets the required throughput specifications when subjected to
vibration levels not exceeding t he V4S vibration level defined below.
Note: The RM S value in the table below is obtained by taking the square root of the area defined by the
g²/hz spectrum from 5 t o 500hz.
Source filename=OPLIMITSIBM CorporationPage 80 of 87