D.C. Winding Resistance
Although a fairly straightforward calculation, the formulas and an example are provided in the effort to achieve completeness.
Calculate the wire length of turn on the core:
L/T = (OD - ID) + 2H
EXAMPLE:
L/T = (0.115 – 0.067) + 2(0.095) = 0.238 in.
Where: OD = 0.115 in. ID = 0.067 in. H = 0.095 in. Np = 26 turns
Next, calculate the wire length on the core:
Wire Length = L/T (Np)
EXAMPLE:
Wire Length = 0.238 (26) = 6.188 in.
Calculate DCR per inch of wire:
EXAMPLE:
For #38HAN Wire, DCR/in = [0.0978 (6664.8)] / 12000 = 0.05432 ohms
Now calculate the wire resistance:
DCR = ( DCR/in ) ( Wire Length )
EXAMPLE: DCR = ( 0.05432 ) 6.188 = 0.336 Ohms