Electromagnetic Compatibility (EMC) Testing
Written by Behnam Feizifar
Electromagnetic compatibility is the equipment ability to function properly in the electromagnetic environment in which it is operating
without getting affected by different electromagnetic disturbances generated by various sources in that environment. EMC testing is a
series of tests carried out to ensure the product's electromagnetic compatibility.
By highly increasing rate of electronic devices used in residential, commercial, as well as industrial sectors, the electromagnetic
compatibility (EMC) tests are becoming more and more important. Manufacturers from various sectors such as home appliances, medical devices,
industrial machineries, railways, automotives, aerospace and military equipment must ensure that the presence of electromagnetic disturbances
will not affect their products' functionality. On the other hand, they are required to comply with the standards and market reuqirements
to maintain their products' quality.
If you would like to know which EMC standards apply to your product, we can help you!
Transient Test System replicates the following phenomena::
- Electrostatic Discharges (ESD): A person becomes electrostatically charged by walking over an insulating floor surface.
The capacity of the body can be charged to several kilovolts and is discharged when contact is made with an electronic unit or system.
The discharge is visible as a spark in many cases and can be felt by the person concerned, who receives a "shock". The discharges
are harmless to humans, but not to sensitive, electronic equipment. The resulting currents cause interference or make entire
systems "crash".
- Electric Fast Transients (EFT) / Burst: Industrial measurement and control equipment nearly always use conventional control
units containing relays or other electro-mechanical switching devices. Fluorescent lamp ballast units, insufficiently suppressed motors
(hair dryers, vacuum cleaners, drills, etc.) are found everywhere in the public power supply. All of these are primarily inductive loads
which generate interference when switched on or off. EFT events, can cause microprocessor units to malfunction or reset, with corresponding
disruption to normal operation.
- Combination Wave Generator (CWG), Ring Wave and 10/700us: Surge events can be generated by lightning phenomena, switching
transients or the activation of protection devices in the power distribution system. A surge itself is influenced by the propagation
path taken so that impulses from the same event may have different forms depending upon where a measurement is taken. Combination Wave
Generators (CWG) simulate a surge event in power lines close to or within buildings. Ring waves are bipolar oscillatory events, only
measured on power lines within a well protected environment. Because of the special impedance characteristics within telephone systems,
surges tend to be longer and are represented by the 10/700us waveform. Mostly the disturbances are tolerable because they are single
events.
- Power Frequency and Pulse Magnetic Fields: Under normal operating conditions, an AC current generates a steady magnetic
field so that equipment, such as monitors, close to AC power lines could suffer interference. Under fault conditions, a sudden high
current level can result in a short duration magnetic field. Lightning strokes or short circuit fault currents in the power network
can generate high level short duration magnetic fields.
- AC & DC Dips/Interrupts: Voltage failures occur following switching operations, short-circuits, response of fuses and when
running up heavy loads. The quality of the electrical power supply is increasingly becoming a central topic of discussion. The interference
sources in the mains, caused by electronic power control with non-linear components e.g. thyristors are used more frequently in domestic
appliances such as hotplates, heating units, washing machines, television sets, economy lamps, PCs and industrial systems with speed-controlled
drives.
