calculation primitive W-shaped transformer best illustrated with an example.Suppose you need to calculate the transformer parameters: supply voltage U1 = 220;output voltage (secondary voltage) U2 = 12V;load current i2 = 0.5A.First, determine the output: P2 = U2 * i2 = 12 * 0.5 = 6W.For such a power can take the magnetic section of about four square centimeters (S = 4)
Next, calculate how much is needed for one volt coils.For the W-shaped transformer is the formula: K =
50 / S = 50/4 = 12.5 turns per volt.
Then, calculate the number of turns of the primary winding: W1 = U1 * K = 220 * 12.5 = 2750 turns.And the number of secondary turns: W2 = U2 * K = 12 * 12.5 = 150 turns.
After that, define the primary current: i1 = (1,1 * P2) / U1 = (1,1 * 6) / 220 = 30mA.And then be able to calculate the diameter of the wire of the primary winding insulation.The fact that the maximum current for copper wire is 5 amperes per square millimeter, so: d1 = 5A / (1 / i1) = 5A / (1 / 0,03A) = 0.15 mm.
Finally, calculate the diameter of the wire of the secondary winding of the formula, d2 = 0,025 * square root of i2, i2 value substitute in this formula milliamp: d2 = 0,025 * 22,4 = 0,56mm.
Measure the diameter of the wire in the collection is possible without the use of precision measuring instruments.Wrap tightly measured lead pencil, measure one centimeter wound and dividing it by the number of turns you get the diameter of the wire.