Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 - Manual (Page 95)

Glossary Glossary-3
gain profiling - A function that dynamically adjusts the gains of the speed loop, the
tension loop, the current major loop, and the position loop as the response of the
system changes due to roll inertia, system losses, and motor torque.
geared-in speed - The instantaneous motor speed, taking into account any gearing
between the motor shaft and spindle, required to produce the top line speed with an
empty core diameter.
inertia - A measure of a body’s resistance to changes in velocity, whether the body is
at rest or moving at a constant velocity. The velocity can be either linear or rotational.
The moment of inertia (WK
2
) is the product of the weight (W) of an object and the
square of the radius of gyration (K
2
). The radius of gyration is measure of how the
mass of the object is distributed about the axis of rotation. WK
2
is usually expressed in
units of lb-ft
2
.
inertia compensation - Provides the change in motor torque required during
acceleration and deceleration to minimize transient error of the controlled process
variable.
JBAR - Defines the time in sections to accelerate the total connected load of a drive
from zero speed to motor base speed with full shunt field excitation. Also identified as
system inertia.
jog - A control function which provides for the momentary operation of a drive for the
purpose of accomplishing a small movement of the driven machine.
KPS - Abbreviation for the proportional gain of an amplifier.
lag - A lag block is a low-pass filter. The frequency components of the input signal that
are higher than the lag or cut-off frequency are attenuated or reduced. Lag blocks are
often used to suppress unwanted noise or high frequency (short duration)
disturbances caused by such phenomenon as backlash in gearboxes. Lag blocks are
so named because they introduce a delay or phase lag between the input and output
signals.
lag/lead - A type of filter that incorporates both a low-pass (lag) and a high-pass
(lead) filter. In the control blocks where the type of filter can be selected (either
lag/lead or lead/lag), the low frequency input corresponds to the break frequency of
the first element in the filter name. In a lag/lead filter, the lag frequency or the low-pass
filter break frequency is lower than the lead frequency. This results in a low-pass filter
with an improved phase margin at higher frequencies. A lead/lag filter is similar except
the lead frequency is lower than the lag frequency and results in a type of high-pass
filter. The ratio input specifies the ratio between the lead and lag frequency (lag and
lead frequencies for a lead/lag filter). For a lag/lead filter with a lag frequency of 10
rad/s and a ratio of 4, the lead frequency will be 40 rad/s.
lead/lag - See lag/lead
lead - See lag/lead
LIMBAR - The per normal value of maximum motor current. It is maximum current in
percent of full load amps / 100.