Parker SSD Drives 590+ DC Digital Drive Manual - Inverter Drive ...

DC590+ Series DC Digital Drive A p p e n d i x D : P r o g r a m m i n g D-46
Inertia Compensation
Many winders need inertia compensation to add or subtract torque during
acceleration and deceleration to maintain constant tension, especially at large
roll diameters. Without compensation, the tension holding capability of open
loop winders diminishes during speed changes causing tension sag.
The inertia compensation characteristics is shown opposite.
For winder applications, inertia compensation is split into two components:
1. Fixed inertia compensation for the fixed motor, transmission and load
components.
2. Variable inertia compensation for the changing roll inertia. This is
especially necessary for high diameter build unwinds and winders.
Line Speed
Speed
acceleration
100%
Forward Torque
(positive armature current)
large diameter roll
Reverse Torque
(negative armature current)
small diameter roll
deceleration
Time
Time