Small-sized portable welding transformer – dream of each inveterate summer resident. With its help it is possible to turn easily heap of iron – into gazebo, the shelter, feeding trough and many other things. For this purpose it is only required to know calculation of quantity of rounds on primary and secondary winding, and to take the three-phase lowering transformer 380/36 as basis, 1-2 kW.
It is required to you
- copper winding wire, copper tire, copper tube
1. Take for primary windings of the welding machine heat-resistant copper winding wire in glass cloth isolation or cotton. Good heat resistance wires in rubber fabric or rubber isolation have. It is not necessary to apply isolation PHV wires as its melting, effluence from windings and short circuit is possible. Therefore remove such isolation from wire and wind it with cotton insulating tape, or without removing over it.
2. Make calculation of rounds of primary and secondary winding. Current density at periodic use of the device is 5 And/mm2, the secondary winding pays off according to formula - P2=Isv*Usv. For example, when welding by electrode with a diameter of 4 mm and current 130-160 A, the power of the II winding will be 160*24=3.5-4 kW, the power of I with losses will be equal to 5-5.5 kW. According to this max the current in it will reach 25A, the section of wire of the I winding will be 5-6 mm2. S of coil-processing wire: 3.14*R2 or 3.14*D2/4, where D - diameter of copper wire without isolation, in mm. If wire aluminum, then it is necessary to increase diameter by 60-70 percent. The number of rounds of the I winding pays off according to formula: W1=(k2*S)/U1, where S-the area of cut of yoke in cm2, k2 - constant coefficient. If the quantity of rounds is equal 240, then do branches from 165, 190 and 215 rounds. As at reduction of number of rounds of the I winding the power of the device and Uxx increases that worsens quality of welding.
3. Take the copper isolated tire which section from 25 mm2 or 35 mm2. Reel up it secondary winding, for this purpose the multicore flexible wire will also approach. It has to have 65... 70 rounds. The main thing to observe the section of power winding. Isolation of wires had to reliable and heatresistant. If insufficient wire section, then it is possible to make winding in two or in three wires. At application of aluminum wire, it is necessary to increase section in 1.6... 1.7 times.
4. Take the copper call 30 mm long and with a diameter of 12 mm. Unrivet it on the one hand, in it drill opening of 10 mm. From other part insert the smoothed-out wires, easy blow of the hammer press out them. For the best contact, on surface of tube make notches core.