appendix

APPENDIX A
Sizing
Generator
Sets with
GenSize�
Overview
APPENDIX A
Rev. Jan 2011
Application Manual – Liquid Cooled Generator Sets
GenSize��is a software application (available on the Power Suite CD from Cummins
Power Generation) for determining the proper size (capacity) of generator sets for your
standby or prime power applications. All of the information needed to order an
appropriate generator set configuration from your local distributor is included in the
recommendation prepared by the software.
In the Library CD that accompanies the Power Suite CD, you can also view and print an
array of product information necessary to properly design a complete power generation
system. Information on the Library CD includes: generator set specification sheets,
technical support information (alternator data, generator set exhaust emissions data,
generator set acoustic data, generator set prototype test summaries) and key drawings
(outline, schematic, wiring diagrams, and accessory installation drawings).
With GenSize you can create, save, retrieve, modify, and delete information within a
project. Load information can be copied and pasted within or between multiple projects.
GenSize handles most load types including various lighting types, HVAC, Battery
Charging, UPS, motors, Fire Pumps and general loading. A user–defined load area is
available for the user to input characteristics of a unique load. GenSize correctly handles
welding, cyclic, and medical imaging loads (where load surge occurs after all loads have
been started and not during the starting sequence itself).
NOTE: When GenSize is used as the basis for sizing a generator set from a manufacturer other than
Cummins Power Generation, be aware that competitive generator sets of the same kW rating may not
be suitable for a given application due to differences in performance. The power system designer can
minimize risk in this situation by specifying a generator set with similar alternator temperature rise,
alternator per unit subtransient reactance, harmonics, and governor transient performance.
In addition to being a tool for viewing generator set performance data, GenSize includes
an easy–to–use graphical interface for entering information about the loads placed on the
generator set, the starting step sequence of the loads, and parameters for the generator
set itself. Although there is no separate manual for GenSize, its context–sensitive Help
files should be sufficient for running the application.
Applications
There are four Applications within the Power Suite: GenSize, Library, GenCalc and
GenSpec.
In GenSize, the project as a whole is displayed on the left side, while the right shows the
contents of any node selected from the left side. This is the core of the application where
loads and sequence are input and defined.
The Library Application allows the user to explore product specifications and data,
application drawings and other pertinent information, and to incorporate this data into a
project report. The Library is accessed through a Library Contents CD. The Library
contents CD may be copied to a PC hard drive for access convenience.
The GenCalc Application includes a Decrement Curve Calculator for the alternators used
on Cummins generator sets. This application is designed to include several future
applications for assistance in designing exhaust and fuel systems as well as other facets
of power systems.
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