Ph.D. Sapa Vladimir, student Politayeva Irina

Kostanai State University A.Baitursynov, Kazakhstan

Antiphase and common mode noise

From interfering in the wires may be considered as in-phase and anti-phase voltages and currents.

Antiphase (transverse) interference occurs between the wires or wire line between the input terminals of the electrical devices (see Figure 1).

Figure 1. SSF-mode interference in the circuit between the power of the desired signal receiver

Antiphase interference occurs through galvanic or field communication or due to common mode conversion in antiphase. Antiphase summed interference with the desired signal and can cause erroneous operation of systems, and as they affect the linear insulation between wires [1, 2].

Figure 2. Esther common mode circuit with grounded point

Common mode (longitudinal) interference occurs between each wire and ground. Common mode noise caused by the potential difference in circuits grounding devices (see Figure 2).

Common mode noise can be caused by currents in the ground (fault currents or lightning currents) or magnetic fields. Common mode interference do not cause interference voltages at the receiver, but the impact on the insulation of the wires relative to the ground and can lead to breakdowns.

Figure 3. Conversion of common-mode noise in antiphase

At high frequency common-mode noise or for large values of capacitance with respect to ground conductors common mode conversion occurs in antiphase (see Figure 2).

Figure 4. Experimental determination of common-mode noise conversion in antiphase

Common-mode voltage is in forward and reverse wire currents that through container and land returned to power.

For different values of the forward and reverse resistance of wires and different capacities C₁ and C, through capacity occur with different meanings currents that create the voltage drop across the resistance of the receiver, and there is a partial or complete conversion of common-mode noise in antiphase.

Measure the degree of conversion to common mode conversion coefficient is antiphase common-mode noise in antiphase [1, 2, 3, 4].

(1)

When complete conversion of K = 1 and is symmetrical in the K = 0. Common mode conversion coefficient in antiphase can be easily determined experimentally by removing the source signal and submitting a short-circuited by the input common-mode voltage system (see Figure 4).

Literature:

1. EMC Basics: a textbook for high schools / edited by Doctor of Technical Sciences, Professor R Karjakin, Altai State Technical University named after II Polzunova. - Barnaul: JSC "Altai Printing Plant", 2007.

2. E. Habiger Electromagnetic compatibility. The basis of its software in the art: Translated from the German / I Kuzhekin; Edited by B Maximov. - Energoatomizdat, 1995. - 304.

3. Electromagnetic compatibility in power engineering: Textbook / G Vagin, A Rags , A Sevost'yanov. - Moscow: Publishing Center "Academy", 2010. - 224.

4. Usachyov A Electromagnetic compatibility: Textbook / A Usachyov. - Ulyanovsk: 2001. - 44.