1 - Schneider Electric SNB
1 - Schneider Electric SNB
1 - Schneider Electric SNB
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Understanding (EMC) phenomena<br />
Type<br />
Source<br />
Transmission<br />
Types of electromagnetic<br />
interference<br />
Transients<br />
1<br />
2<br />
3<br />
4<br />
5<br />
The term «transient» denotes impulsive spikes picked up by electric circuits and encountered in conducted form<br />
on power supply cables and at control and signal inputs of electrical or electronic equipment.<br />
Characteristics of standardised transients (IEC 1000-4-4 type)<br />
The significant features of these disturbances are as follows:<br />
- Very short duration of pulse rise time 5 ms<br />
- Pulse duration 50 ms<br />
- Repetitive phenomenon: pulse bursts for roughly 15 ms<br />
- Repetition frequency : successive bursts roughly every 300 ms<br />
- Low energy pulses 1-10 -3 joule<br />
- High amplitude of overvoltage ≤ 4 kV<br />
Example :<br />
U<br />
Pulse<br />
t<br />
Time<br />
representation<br />
100 µs<br />
5 ms<br />
Repetition period depends on the level of the test voltage<br />
U<br />
Pulse burst<br />
t<br />
15 ms<br />
Length of burst<br />
Burst period 300 ms<br />
Te<br />
14
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