Rockwell Automation Motion Analyzer Software - Manual (Page 252)

252 Rockwell Automation Publication MOTION-UM004B-EN-P - October 2012
Chapter 3 Understanding Your System Solution
3.3.2. Resistive Brake Module
Check Resistive Brake Module to enable selection and analysis of resistive brake
modules (RBM).
RBM modules provide controlled motor braking by connecting resistors across
the windings. An RBM module does not stop the motor if the axis has a thrust,
an external force, or a gravity force as a result of being inclined. The RBM
module only produces motor torque if the motor is moving and may act as a
speed limiter. When this happens, it is essential to use a fail-safe brake. The motor
brake may not be sufficient to stop the system and should not be applied when it
is in motion.
The stopping behavior depends on the initial velocity, inertia, contactor delay,
and the value of resistance in the RBM module. This tab enables you to select the
optimum resistive brake module.
Table 148 - Resistive Brake Module Properties (refer to Figure 195 )
3.3.3. Load Data
Table 149 - Load Data Properties (refer to Figure 195 )
Parameters Description
Resistive Brake
Modules
Start Speed
Select the Max. Appl. Speed option if you are sure this value cannot be
exceeded.
Select the Max. Motor Speed option for a high level of security. This is generally
the worst case scenario.
Plot Time
This sets the time scale for the distance calculation and graphical display. To
zoom in on the left-hand end of the graph, decrease the Plot Time. Increase the
Plot Time if the system has not stopped, to evaluate longer stopping times, and
to view the ultimate speed when not stopping.
Parameters Description
Load Data
Mechanism Data
Select this option to use the External Torque and Load Inertia values from the
system data that has been entered in previous tabs. This is the torque on the
motor produced by any external torque or force.
User Defined
Select this option to manually enter External Torque and Load Inertia values. In
some cases, the maximum inertia/thrust may not coincide with the maximum
speed. When this happens, the default (maximum speed and inertia/thrust)
may produce an over-cautious solution. Advanced users may want to enter
their own value for the inertia and thrust torque (with reference to the motor)
for the maximum speed condition.