Standard frequency

Area	Electrical engineering
title	IEC standard frequencies
Brief description:	Standard frequencies for single-phase AC and three-phase systems, for systems on ships, for rail systems, for tools and for aircraft
Latest edition	2010-03
ISO	-

Area	Acoustics
title	Standard frequencies
Brief description:	Standard frequencies for acoustic measurements
Latest edition	1997-08
ISO	266

A standard frequency is either a standard frequency for acoustic measurements according to EN ISO 266 or an IEC standard frequency for technical applications according to EN 60196.

Standard frequencies for acoustic measurements according to EN ISO 266

Standard frequencies for acoustic measurements according to EN ISO 266 (formerly DIN standard DIN 45401) are defined frequencies at which measurements in the fields of acoustics and electroacoustics are to be carried out.

Since the frequency f = 1000 Hz is the usual center frequency in the acoustic range, the standard frequency sequence was set up and down based on f = 1000 Hz. The standard frequencies listed in the table should be used as center frequencies for octave filters and third- octave filters . The filter center frequencies of the first series are identical to the filter corner frequencies ( cutoff frequencies ) of the second series and vice versa. For measurements in octave steps, the frequency sequence containing the frequency 1000 Hz should be preferred.

Table of standard frequencies according to EN ISO 266

1st octave sequence	31.5						63						125						250
2nd octave sequence				45						90						180
1st sequence of thirds	31.5		40		50		63		80		100		125		160		200		250
2nd sequence of thirds		35.5		45		56		71		90		112		140		180		224		280
1st octave sequence					500						1000						2000
2nd octave sequence		355						710						1400						2800
1st sequence of thirds	315		400		500		630		800		1000		1250		1600		2000		2500
2nd sequence of thirds		355		450		560		710		900		1120		1400		1800		2240		2800
1st octave sequence			4000						8000						16000
2nd octave sequence						5600						11200						22400
1st sequence of thirds	3150		4000		5000		6300		8000		10,000		12500		16000		20000		25,000
2nd sequence of thirds		3550		4500		5600		7100		9000		11200		14000		18000

IEC standard frequencies

IEC standard frequencies are those frequencies (up to 10,000 Hz) that are to be used for single-phase AC and three-phase systems, for systems on ships, for rail systems operated with AC, for tools and for aircraft.

For energy supply and systems on ships, 50 Hz and 60 Hz are the standard frequencies.

For railways, 16⅔ Hz, 50 Hz and 60 Hz are the standard frequencies.

For tools, the standard frequencies are divided into series I, 50 Hz and series II, 60 Hz. The entries marked in bold in row I are preferred values.

Row I.	50	100	150	200	250	300	400	500		600	750
I ff	1,000	1,200	1,500	2,000		2,400	3,000		4,000	8,000	10,000
Row II	60		180				400		540	720
II ff	1,000	1,440			2,160	2,800		3,420

400 Hz is the standard frequency for aircraft.

Norms

DIN 45401: 1985-02 Acoustics, electroacoustics, standard frequencies for measurements; withdrawn, document was replaced by: DIN EN ISO 266: 1997-08
EN ISO 266: 1997 Acoustics - Standard frequencies (ISO 266: 1997)
EN 60196: 2009 (VDE 0175-3: 2010-03) IEC standard frequencies
EN 50163: 2004 (VDE 0115-102: 2005-07) Railway applications - Supply voltages for railway networks.

Individual evidence

↑ For traction current primarily EN 50163 (VDE 0115-102): 2005-07 Railway applications supply voltages of railway networks and DIN EN 50163 / A1 VDE 0115-102 / A1: 2008-02. The traction current was definitely switched from 16 2/3 to 16.7 Hz on October 16, 1995 (simultaneous switchover in Switzerland, Austria and Germany).

[1] For traction current primarily EN 50163 (VDE 0115-102): 2005-07 Railway applications supply voltages of railway networks and DIN EN 50163 / A1 VDE 0115-102 / A1: 2008-02. The traction current was definitely switched from 16 2/3 to 16.7 Hz on October 16, 1995 (simultaneous switchover in Switzerland, Austria and Germany).