APPENDIX A-3: APPLICABLE SECTIONS OF THE NATIONAL ELECTRIC CODE(NEC)

Example 1, Page number 594

In [1]:
#Variable declaration
hp = 5.0       #Power rating of motor(hp)
V = 220.0      #Voltage rating of motor(V)
Va_a = 180.0   #Armature voltage(V)
Va_b = 240.0   #Armature voltage(V)

#Calculation
I1 = 27.0              #Current(A). From Appendix A-3 table for 180V
I_L1 = I1*(Va_a/V)     #Full load current(A)
I2 = 20.0              #Current(A). From Appendix A-3 table for 240V
I_L2 = I2*(Va_b/V)     #Full load current(A)

#Result
print('Case(a): Full-load current for armature voltage of 180 V , I_L1 = %.f A' %I_L1)
print('Case(b): Full-load current for armature voltage of 240 V , I_L2 = %.f A' %I_L2)

Case(a): Full-load current for armature voltage of 180 V , I_L1 = 22 A
Case(b): Full-load current for armature voltage of 240 V , I_L2 = 22 A

Example 2, Page number 594

In [1]:
#Variable declaration
hp = 10.0      #Power rating of motor(hp)
V = 600.0      #Voltage rating of motor(V)
Va = 550.0     #Armature voltage(V)

#Calculation
I = 16.0              #Current(A). From Appendix A-3 table for 550 V
I_L = I*(Va/V)        #Full load current(A)

#Result
print('Line current at rated load , I_L = %.1f A' %I_L)

Line current at rated load , I_L = 14.7 A