ShortCkt 1.0


ShortCkt is designed to calculates the three-phase short-circuit currents. It is based on ANSI/IEEE Std 141 and 242.
The intent of this program is to provide a means for determining the numerical value of the symmetrical short-circuit rms current.
The application returns with the maximum symmetrical short-circuit current available 1/2 cycle after the short circuit starts.  The program considers the power company system, generators, synchronous motor and induction motors as basic sources of fault current. Transformers and cables are taken into consideration for total impedance calculations. Calculations of fault current are usually made to ensure that the interrupting capacities of the equipment are adequate to handle the currents available at their locations.  In most system the three-phase fault is frequently the only one calculated.

ShortCkt has the following assumptions:

1- The fault is "bolted"(zero impedance).
2- Load currents are ignored.
3- Voltages of power supplies are equal to their nominal values at no load.
4- Motors are assumed to be running with their rated voltage.


The program is intended for electrical professionals and inspectors with basic knowledge o the calculation procedures of fault currents. Meeting Code requirements is responsibility of the user.
The program is more accurate than the Fault Current Tables commonly used by inspectors and electrician. All impedances are calculated as complex numbers for more accuracy (Ex. Z = R + jX).
The program is very easy to use and includes a feature for inserting any type of device (circuit breaker, panel board, reactors, cables, etc.) in serial with the circuit conductors. This option is accomplished by the use of R and X buttons. 
ShortCkt automatically provides the impedance of the circuit conductors, based on 75(C average temperature.  If the user wants to use another impedance values, instead of the one provided by the program, just enter the resistance and reactance using R and X buttons and set to 0 ft the length of the circuit.


HOW TO USE IT

1. Enter the utility fault capacity (or the available short-circuit MVA of source).
(Default =500 MVA)(Maximum: 99,999 MVA).
	
2. Enter the transformer kVA rating and Impedance (in percent)(Maximum: 99,999kVA).

3. Enter the sum of induction motor horsepower, connected to the system. Do the same with the synchronous motors. Consider all motors at each location, which may be running even though at partial load. (Maximum: 9,999 HP).

4. Enter the voltage of the system (line-to-line)(Maximum: 999,999 Volts). This is the nominal voltage at the point of short-circuit.

5. Select the wire size, cable type, conductors metal (copper/aluminum), and the conduit type.

6. Enter the length of the feeder (feet)(Maximum: 9,999 feet).

7. Tap the R and X buttons and enter the added resistance and reactance, in serial with the circuit conductor impedance. R and X can be used to introduce the impedance of devices like breakers, reactors, etc. They can be used to replace the impedance of the circuit conductors, automatically calculate by the program. Entering 0 ft as length of feeder is an easy way to disable the automatic calculated impedance of cables.

8. Tap the Calculate button.



INSTALLATION:


Using your favorite program, install the following files:

	PocketC.prc*		PocketC  v3.0 runtime (from OrbWorks)
				(This file must be installed first, if 				you do not have it)
	ShortCkt.prc		Application
	Pocketgu.pdb	  	Library from Klaus Rindtorff
	

	If you have the latest version of those programs installed, you do not need to re-install them.


Files Included:
	
	ShortCkt.prc			ShortCkt application
	PocketC.prc*			PocketC runtime (from OrbWorks)
	Pocketgu.pdb	    		Library from Klaus Rindtorff		
	MathLib.prc*			Math shared library.
	Instructions			MSWord document for nstructions
	Readme.txt			This document
	
Why should you register this program?

You will be able to download and use new versions of this applet for free, using the same registration number.

You will be given one month to evaluate the program.

When you "forget" to register the applet will expire.

After you register you will receive an e-mail with your personal
registration number. 



LEGAL:

ShortCkt is not a certified program of any sort. 
The applet requires PocketC runtime (by Jeremy Dewey: http://www.orbworks.com) and libraries of PoketGui (PocketGui and PocketGuiLib by Klaus Rindtorff: rindtorf@us.ibm.com) for its operation. 
The application is provided AS IS, with no guarantee of fitness for any particular task. The user assumes all responsibility for its use.


Please send suggestions, comments, and bug reports to the author:
Arismendi Hernndez
E-mail: ar.hernandez@codetel.net.do











