Saturday, September 11, 2021

Sharp EL-5500 III & PC-1403: Fan Laws and Voltage Drop Percentage

 Sharp EL-5500 III & PC-1403: Fan Laws and Voltage Drop Percentage



Fan Laws 

The program will calculate RPM_new (Revolutions per Minute), SP_new (Static Pressure), and BHP_new (Brake Horsepower).  

Inputs:
CFM_old:  Cubic Feet of Minute - old
CFM_new:  Cubic Feet of Minute - new
RPM_old:  Revolutions per Minute - old
SP_old:  Static Pressure - old
BHP_old:  Brake Horsepower - old

Outputs:
RPM_new
SP_new
BHP_new

Sharp EL-5500III/PC-1403 Program:  Fan Laws
RUN 700 (or whatever line you designate)

700 PRINT "FUN LAWS"
703 INPUT "CFM.OLD? "; A
706 INPUT "CFM.NEW? "; B
709 INPUT "RPM.OLD? "; C
712 INPUT "SP.OLD? "; E
715 INPUT "BHP.OLD? "; G
718 D = B*C/A
721 F = E*B^2/A^2
724 H = G*B^3/A^3
727 PRINT "RPM.NEW: "; D
730 PRINT "SP.NET: "; F
733 PRINT "BHP.NEW: "; H
736 END

Example

Inputs:
CFM.OLD:  1250 CFM
CFM.NEW: 1600 CFM
RPM.OLD:  840 RPM
SP.OLD: 4 in
BHP.OLD: 7 BHP

Results:
RPM.NEW: 1075.2 RPM
SP.NEW: 6.5536 in
BHP.OLD:  14.680064 BHP

Source:
Calculated Industries "Sheet Metal/HVAC Pro Calc User's Guide" 2021

Voltage Drop Percentage

This program calculates the voltage drop percentage for wires that operate in 75°C, given the wire length from the object to the power source for wires 2, 4, 6, 8, 10 and 12.  The NEC 2020 code is used.  

Sharp EL-5500III/PC-1403 Program:  Voltage Drop Percentage
RUN 500 (or whatever line you designate)

500 PRINT "VOLTAGE DROP 75 DEG"
501 CLEAR
503 DIM S(5)
506 REM NEC 2020
509 S(0) = .194
510 S(1) = .308
511 S(2) = .491
512 S(3) = .778
513 S(4) = 1.24
514 S(5) = 1.98
530 INPUT "VOLTS? "; V
533 INPUT "CURRENT? "; A
536 INPUT "WIRE LGTH TO PWR (FT)? "; L
539 INPUT "#2,4,6,8,10,12? "; J
542 J = J/2 - 1
545 W = S(J)
548 D = (A*W/1000*2*L) / V * 100
551 PRINT "VD = "; D; "%"
554 END

Example

Inputs: 
VOLTS:  80 V
CURRENT: 36 A
WIRE LGTH TO PWR (FT): 140 ft 
#8 wire

Result: 
VD = 9.8028%

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

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