Rockwell Automation 141A Mounting Ssystem MCS Star Tutorial - Manual (Page 5)

3
Below is the list of motors and loads that will be used in our tutorial. We need to confi gure a
horizontally mounted busbar assembly for a line voltage of 480V 60 Hz, control voltage 120V
60 Hz, designed per UL standards, in a 900 mm wide cabinet and have a short-circuit current
rating (SCCR) of 5 kA. Th
e 12 loads are as follows:
Motor 1 DOL 30.0 Hp 40.0 A
Motor 2 DOL 10.0 Hp 14.0 A
Motor 3 DOL 15.0 Hp 21.0 A
Motor 4 Reversing 15.0 Hp 21.0 A
Motor 5 Reversing 1.5 Hp 3.0 A
Motor 6 Drive 0.5 Hp 1.1 A
Resistive 7 Circuit Breaker – 40.0 A
Motor 8 Soft Starter 10.0 Hp 14.0 A
Motor 9 DOL w/E1+ OLR 3.0 Hp 4.8 A
Motor 10 DOL w/E3 OLR 3.0 Hp 4.8 A
Motor 11 Reversing w/E1+ OLR 2.0 Hp 3.4 A
Motor 12 Reversing w/E1+ OLR 2.0 Hp 3.4 A
Estimated Total Ampacity: 170.5 A
In North America, busbar should be sized at 125% of the FLA of the largest motor + the sum
of all other motor FLAs + 125% of all non-motor loads. Based upon the loads above, the busbar
needs to be rated at least 190.5 A. Let’s use the 20x5 busbar rated 320 A.
We also need to decide how we will feed power to the racks, as well as protect them.
If we choose a circuit breaker to do both jobs, it will save us time and space. Circuit breakers in
North America should be sized at least 125% of the total load and up to 250% of the load.
Let’s choose a 250 A circuit breaker for this application.
We now have enough information to design a system using MCS Star.
To save your design, click on the File Menu > Save Project. If you have not saved the project
previously, you will be presented with a standard windows save dialog where you can browse to a
folder, specify a fi lename and save your project.
Saving this project will allow you to download the project output to Rockwell Automation
Temperature Rise Calculation Software (TRCS).
Be sure to save your project often to ensure that confi guration work is not lost.
Step 1:
Identify System
Loads and Parameters