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6.2.1
Conducted noise immunity
Noise is specified as a periodic and random distribution of frequencies covering a band from DC to 10 MHz.
Maximum allowed noise values given below are peak-to-peak measurements and apply at the drive power
connector.
+5V
0 to 100 kHz
150mV
100 kHz to 10 MHz
100mV
6.2.2
Power sequencing
The drive does not require power sequencing. The drive protects against inadvertent writing during power-up
and down.
6.2.3
Current profiles
Figure 3 identifies the drive +12V current profile. The current during the various times is as shown:
+12 Volt Current during spindle start – Typical Amperes
2.5
2
1.5
1
.5
0
Figure 3.
Typical Cheetah 9LP FC drive +12V current profile
T0
Power is applied to the drive.
T1
Controller self-tests are performed.
T2
Spindle begins to accelerate under current limiting after performing internal diagnostics.
T3
Spindle is up to speed and the Head-Arm restraint is unlocked.
Note: All times and currents are typical. See Table 1 for maximum current requirements.
6.3
Power dissipation
Typical seek power dissipation is 15.6 watts (53 BTUs per hour) of DC power average at nominal voltages. Typ-
ical power dissipation under idle conditions is 13.7 watts (47 BTUs per hour).
+12V (with spindle motor not running)
150mV
100mV
Average value of waveform
T2
T1
T0
T3
0
5
10
Cheetah 9LP FC Product Manual, Rev. C
15
20
25
Seconds
Envelope of waveform
30
35
40
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