What Is Different? Between Impulse Noise and Electrical Fast Transient Burst】

【What is different? Between Impulse Noise and Electrical Fast Transient Burst】

The Inquiry about "a distinction between an impulse noise simulator (following and our company model INS series) and a Fast transient Burst simulator (following and our company model FNS series)" is one of the major questions in a lot of quries from customers. Herewith the difference is focused and presented.

The phenomenon which are reproduced and backgraound Both INS and FNS reproduce phenomenon of back electromotive energy noise which may be generated in ON/OFF of power supply switching (like a gas insulated braker and/or electromagnetism relay, etc.). INS was introduced by Mr. Manohar L.Tandor (at that time worked in I.B.M) as a simulator of the high frequency noise to data processing apparatus in the 1960s, and the computer maker of those days adopted it in the 1970s, and it spread widely. FNS is indicated as a basic standard of the immunity type test which reproduces the malfunction by the noise phenomenon of switching ON/OFF and adopted not only in Europe but also world-wide. The 1st edition of Standard for this test was issued as IEC801-4 in IEC TC65 (Industrial Process Controls) in 1988. Then, in order to adopt to all the electric devices, IEC1000-4-4 was issued in 1995. Moreover, in order to differenciate the numbering between ISO and IEC, “60000” has been added to the Stadanrd number. Consequently, it has been named as IEC61000-4-4.

output waveform Rise time / the pulse width [INS] It is a rectangular wave whose pulse width is 50ns-1μs and rise time is less than 1ns.

500V/ div 400ns/ div 500V/ div 1ns/ div

[FNS] It is a triangular wave whose pulse width is 50ns and rise time is 5ns..

500V/ div 40ns/ div 500V/ div 4ns/ div

- Repetition intervals (Image and figure comparison) [INS] [FNS]

Variable till 10ms-999ms *1 Variable till 0.5μs-999Ms *2

*1 : 4kV type of INS is 16ms-999ms. *2 : Guaranteed accuracy is 5kHz - 100 kHz (IEC standard requirement).

Frequency characteristic [INS] Including broadband noise frequency more than 1GHz.

[FNS] The frequency components ceases below 400MHz.

Output voltages [INS] Maximum voltage is available up to 4,000V. Although there is no specific provisions, the measure test voltage is basically 2,000V and it may be increased to 3,000V for taking some margin into the account. [FNS] Maximum voltage is available up to 4,800V. IEC Standard requires up to 4,000V..

Noise injection method [INS] To power lines : Normal mode (between a lines-line), and common mode (between a line - grounds) To signal lines : Magnetic field coupling and/or capacitive coupling which use clamps Featuring Normals mode injection taking power supply conditions in Japan into the account [FNS] To power lines :ONLY commonmode (between a line-ground To signal lines : Capacitive coupling which uses clamp

Conforming Standards and Guide line [INS] NECA TR-28 (Nippon Electric Control Equipment Industries Association) JEM-TR177 (Japan Electrical Manufacturers' Association) JEC0103_2005 (Institute of Electrical Engineers) The individual industry and manufacturers private standards (Automobie, Consumer equipments, Industrial equipments, etc.) [FNS] IEC61000-4-4 (International Electrotechnical Commission) JIS C 61000-4-4 (Japanese Industrial Standards Committee) The individual industry and manufactueres private standards (automobile etc.)

Conclusion Both the Impulse Noise test and Electrical Fast Transient Burst (EFT/B) test purpose withstand test for back electromotive energy noise which may be generated in ON/OFF of power supply switching. The repetition frequency of EFT/B tests is very fast, and it is broadly adopted based on provision of international standard IEC61000-4-4 to world-wide including Japan as JIS C 61000-4-4. On the other hand, although the Impulse Noises tests are not requested In international standards, it is standardized in some Japanese authorized committees or associatons as it is descrived in the above for point of the view “it enables to verify immunity quantitativeness against the noise in spreaded broad band range and such rectangular waved impulse noise immunity test which can compare with the actual recordd in the markets should be standardized” . Therefore, the simulator has been popularly used by Japanese electrical manufacturers even they establish the factilites in overseas contries and carry on the test there. The rise time must be more rapid and frequency component lasts until higher range than EFT/B test and the tests both in normal mode and common mode can be done. Those can realize more severe tests than EFT/B test and tests in normal mode because of Japanese real power supply condtions. The reasons cause worth of the impulse noise tests in addition to EFT/B tests. Eventually, there are many Japanese manufacturers keep on doing both EFT/B and impulse noise tests in order to maintain and improve their products quality.

[INS and a FNS comparative table]

PARAMETER INS (IMPULSE NOISES) FNS(EFT/B NOISE) *3

Output waveform Rectangular (square) Triangular

Rise times Less than 1ns 5ns

The pulse width 50ns-1000ns 50ns

Output voltages Max. 4000V Max. 4800V

Repetition frequency Max 100Hz *4 Max 2MHz *5

Frequency components Including high frequency more than 1GHz 400MHz or less

Test mode (To power lines) Common mode / Normal mode Only common mode

Test mode (To signal lines) Capacitive coupling / magnetic field coupling Capacitive coupling

Conforming Standard or NECA TR-28 IEC61000-4-4 Guildline JEM-TR177 JIS C 61000-4-4 JEC 0103_2005 Individual industry standards or Individual industry standards or private private standards standards

User Mainly Japanese Worldwide

* 3: EFT/B noise : Abbreviated name of Electrical Fast transients Burst noise * 4:100Hz is specification of the simulator whose output voltages is 2kV. (In case of 4kV output simulator, this parameter can be 60Hz) * 5: The requirement of the Standards is 100kHz.

<< Difference between old model and current model in Impluse Noise Simulator (INS series)>> Digitals controlling circuits are built in the current ones (The old ones are controlled with analog oscillation circuits) Therefore, there may be difficulty to take same tests results between the old ones and current ones due to slight dispersion of the noise generation timing, etc. even the rise up time of the waveforms and pulse durations are identical. It is recommended that scheming and devising problemless transfer from the old ones to the current ones with the simultaneous using for a while.