AN2512 datasheet(25/38 Pages) STMICROELECTRONICS

Part #	AN2512

Description	This application note describes how to design

PDF	38 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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25 / 38 page

AN2512

Three-phase systems

25/38

Figure 14.

Graph of voltage and frequency influence on phase n.3

Appendix A

Three-phase systems

Three-phase is a common method of electric power transmission. It is a type of polyphase

system used to power motors and many other devices.

The currents are sinusoidal functions of time, all at the same frequency but with different

phases. In a three-phase system the phases are spaced equally, giving a phase separation

of 120°. The frequency is typically 50 Hz in Europe and 60 Hz in the US and Canada.

Figure 15.

Instantaneous voltage (or current) in one voltage cycle of a three-phase

system

The three phases could be supplied over six wires, with two wires reserved for the exclusive

use of each phase. However, they are generally supplied over three or four wires:

●

Three phases, 3-Wire DELTA service which has no neutral and 220 V between phases

-0,7

-0,5

-0,3

-0,1

0,1

240

220

180

120

I[A]

-0,5

-0,3

-0,1

0,1

I[A]

AN2512 Datasheet(PDF) 25 Page - STMicroelectronics