Power transformers are indispensable companions for power lines of railways and industrial enterprises, as well as elements of the landscape of any city. Thanks to them, it is possible to more economically transmit electricity over long distances, and then convert it to a level that is acceptable in everyday life. For such purposes, step-up and step-down power devices are used.
Instructions
Step 1
Calculate the max load current (In) and voltage on the II-nd winding (U2). To do this, use the formulas. The current flowing through the II-nd winding of the transformer:
I_2 = 1.5 I_n, where: I_2 - current passing through the winding of the 2nd transformer, A;
I_н - maximum load current, A.
The power consumed by the rectifier from the second winding of the transformer:
P_ (2) = U_2 I_2, where: U_2 - voltage on the II-th winding, V;
I_2 - max current through the II-nd winding of the transformer, A.
Step 2
Calculate the transformer power:
P_mp = 1.25P_2, where P_mp is the power of the transformer, W;
P_2 - maximum power that is consumed from the second winding of the transformer, W.
In the event that the transformer has several secondary windings, then calculate the total power and only then the total power of the transformer itself.
Step 3
Find the amount of current that flows in the I-th winding:
I_1 = P_mp U_1, where I_1 is the current through the winding 1, A;
P_mp- calculated power of the transformer, W;
U_1- voltage on the I-th winding of the transformer (network).
The area required for the cross-section of the magnetic core:
S = 〖1, 3 * 〖(P〗 _mp〗 ^ (1/2)), Where: S is the section of the magnetic core, 〖cm〗 ^ 2;
P_mp- transformer power, W.
The number of turns of the primary (network) winding:
W_1 = 50U_1 / S, where: W_1 is the number of winding turns;
U_1- voltage on the I-th winding, V;
S - section of the core of the magnetic circuit, 〖cm〗 ^ 2.
Step 4
Count the number of turns on the second winding:
W_2 = 55U_2 / S, where: W_2 is the number of winding turns;
U_2- voltage on the II-th winding, V;
S - section of the core of the magnetic circuit, 〖cm〗 ^ 2.
Determine the diameter of the wire of the transformer winding as:
d = 0.025 * I, where: d-wire diameter, mm;
I-current through the winding, mA.
Step 5
After calculating, select transformer iron and wires, mount the frame and make a winding. It should be borne in mind that W-shaped transformer plates can have a different window area, therefore it is necessary to check whether the wires will fit on the transformer frame, whether the plates that you have chosen are suitable. To find out, you need the power of the transformer, which we previously learned to multiply by 50, this value will characterize the required window area in 〖mm〗 ^ 2. This iron can be used in a transformer if the obtained value is greater than or equal to the area in the selected plates. When choosing the core of the magnetic circuit, keep in mind that the ratio of the thickness of the set (the ratio between the sides of the core) and the width of the core should be in the range from 1 to 2.
