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Basic Knowledge of ESD / EFT / Surge / Ground Loop. Joshua Lin. Agenda. 1. ESD - IEC 61000-4-2 . 2. EFT - IEC 61000-4-4. 3. Surge - IEC 61000-4-5 / IEC 61643-21. 4. Ground Loop. 5. Recap and Q&A. ESD Introduction. What is ESD?. Electro Static Discharge(ESD)
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Basic Knowledge ofESD / EFT / Surge / Ground Loop Joshua Lin
Agenda 1 ESD - IEC 61000-4-2 2 EFT - IEC 61000-4-4 3 Surge - IEC 61000-4-5 /IEC 61643-21 4 Ground Loop 5 Recap and Q&A Confidential
What is ESD? • Electro Static Discharge(ESD) • Rapid transferof electrostatic charge between two objects.
Where ESD Comes from? • Human Body Model (HBM) • Discharge from a bare finger to ground. • Machine Model (MM) • Discharge from the device to ground. • Charged Device Model (CDM) • Discharge to a grounded metal surface.
Why We Need ESD Protection? • Damage or destroy computer or hardware components. • While electronic circuits become smaller, the ESD protection requirements become more demanding.
What is ESD Standard? • IEC 61000-4-2
The Spec of ESD Standard • Air discharge Test • Insulating surfaces • Contact discharge Test • Conductive surfaces
What is EFT? The voltage developed across an inductance L by a changing current I is V = -L · dI/dt • Electrical Fast Transient (EFT) • Short-lived oscillation in a system caused by a sudden change of voltage or current. • Where EFT comes form? • The instantaneous of switching, an infinite dI/dt is generated.
Why We Need EFT Protection? EFT cause interfering signals from different paths. • Coupled into a nearby electronics device by inductive coupling. • Enter the product via the cable connections.
What is EFT Standard? • IEC 61000-4-4
What is Surge? • It is a transient wave of electrical current, voltage, or power propagating along a line or a circuit and characterized by a rapid increase followed by a slower decrease.
Where Surge Comes from? • Power system switching transients • Major power system switching disturbances. • Resonating circuits associated with switching devices. • Various system faults. • Ex: short circuits, arcing faults to the grounding system of the installation. • Lightning transients • Lightning coupling into the common ground paths of the system. • Direct lightning stroke. • Indirect lightning stroke.
ON OFF Why We Need Surge Protection? It can cause wear and tear on your electronic devices, or in severe cases even destroy them.
What is Surge Standard? • IEC 61000-4-5
The Spec of Surge Standard • IEC 61000-4-5
What is Surge Standard? • IEC 61643-21 Telecommunications and signaling networks. Define different categories by waveform. C2 covers most of waveforms for surge energy. Confidential
The Spec of IEC 61643-21 • VS. Moxa ISD series If there is probability to hit by thunder directly, please choose class I surge protector ISD series Cover Range ISD series devices are belonged to class II
What is Ground Loop? • Ground loop • According to the Telecommunications Industry Association (TIA)Ground loop in an electrical system is an unwanted current that flows in a conductor connecting two points that are nominally at the same potential, but are actually at different potentials
Why We Need Isolation? X • Prevent current from flowing between two communicating points. • The potential for current surges can damage equipment. • Different ground potentials and ground loops are to be avoided.
How to Do Isolation? • There many types of isolation • Optical Isolation • Magnetic Isolation • Capacitor Isolation • … Circuits Isolation Circuits Data Signal Signal Data
How to Know the Protection Level? • - Datasheet (ex. MGate MB3170I) • ESD, EFT, Surge • Ethernet Isolation • Serial Isolation • Uport 1xxxI • MGateMBxxxI • MGate 4101I/5101/5102/5105 • NPortxxxxI
Q2. ESD and Surge and EFT all are energy; which one has the biggest level of energy? Q3. ESD and Surge and EFT all are energy; which one has the longest duration time? Surge > ESD > EFT Surge > ESD > EFT
Q4. What’s the main purpose between Isolator and surge protector? • Isolator: • Different ground potentials and ground loops are to be avoided. Usually, the ground loop is the energy in long duration. • Surge protector: • Prevent from transient energy, such as lightning transients & power system switching transients.
Q5. How to Select Suitable Surge Protector? ISD-1210/1230 ISD-1110/1130 Office • Harsh Environment • IEC 61643-21 C2 • Surge Level: 20kV • Closer outdoor • (Lightning and thunder) • Demarcation point • High voltage power system • High power motor (>4kW) • Critical application • Expensive equipment • General Purpose • IEC 61000-4-5 • Surge Level:4kV • Engine • Low power motor (<4kW) • Low voltage power system Outdoor Cabinet IT Server Room Indoor Cabinet Laboratory Confidential The Kitchen, CNC room…etc