The spindle motor or the spindle shaft is responsible for turning the hard disk platters, allowing the hard drive to operate. A spindle motor must provide stable, reliable and consistent turning power for thousands of hours of often continuous use, to allow the hard disk to function properly because many drive failures are actually failures with the spindle motor, not the data storage systems.
The spindle motor of a hard disk must have the following quality to live long and to keep your data, secure for a long time:
- It must be of high quality, so it can run for thousands of hours, and tolerate thousands of start and stop cycles, without failing.
- It must be run smoothly and with a minimum of vibration, due to the tight tolerances of the platters and heads inside the drive.
- It must not generate excessive amounts of heat or noise.
- It should not draw too much power.
- It must have its speed managed so that it turns at the proper speed.
To meet these demands, all PC hard disks use servo-controlled DC spindle motors. Hard disk spindle motors are configured for direct connection. There are no belts or gears that are used to connect them to the hard disk platter spindle. The spindle onto which the platters are mounted is attached directly to the shaft of the motor.
The platters are machined with a hole of the exact size of the spindle, and are placed onto the spindle with separator rings between them to maintain the correct distance and provide room for the head arms. The amount of work that the spindle motor has to do is dependent on following factors:
- The size and number of platters: Larger platters and more platters in a drive mean more mass for the motor to turn, so more powerful motors are required. The same is true of higher-speed drives.
- o Power management: Today, users increasingly want hard disks that will spin up from a stopped position to operating speed quickly, which also requires faster or more powerful motors.
As in newer hard disks the spindle speed is supposed to be an important issue it has also become an important point in the hard disks to control the amount of noise, heat and vibration generated by the hard disks due to high spindle speed.
Some newer drives, especially 7200 and 10,000 RPM models can make a lot of noise when they are running. If possible, it is a good idea to check out a hard disk in operation before you buy it, to assess its noise level and see if it bothers you; this varies greatly from individual to individual. The noise produced also varies to some extent depending on the individual drive even in the same family. Heat created by the spindle motor can eventually cause damage to the hard disk, which is why newer drives newer hard disks are giving more attention to their cooling.