Hitachi SJ300-EL Series, Instruction Manual Supplement

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Chapter 4
–
Adjustment
4.4 Adjustment of Inertia
Inertia J (H024 and H034) should be adjusted to avoid overshoots or undershoots as
shown in Figure 2.1. These undershoots or overshoots decrease with an increased
value of inertia J. Increase the value of inertia J gradually to eliminate overshoot and
undershoot. The figures below show the frequency of inverter output obtained from the
analog voltage (AM terminal). The output of this frequency monitor signal is identical to
actual rotation speed in vector mode with feedback.
Figure 2.2 Characteristics after inertia adjustment
Brake release
signal
Figure 2.1 Characteristics before inertia adjustment
Overshoot
RPM
monitor
Creep speed
Figure 2.1 Characteristic before inertia
dj t t
Ascent
Undershoot
Motor
current
Torque
monitor
Motor
current
Torque
monitor
RPM
monitor
descent ascent
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