Flashcards in Ch. 2 - Electromagnetic Compatibility.csv Deck (22)
Electromagnetic spectrum includes light, radio waves, microwaves, IR radiation, UV rays, X-rays & gamma rays known collectively as the _________.
Radiated interference enters electronic devices primarily by means of:
-Proximity to interfering sources
-Missing or inadequate gaskets/enclosures
-Missing or inadequate bonding & grounding system components
-Missing or inadequate device or cable shielding
(not solid state device)
ITS designer responsible for EMI? EMC?
Yes - bonding/grounding/shielding
Internal EMI sources are typically:
-Electrical power supplies
(not electrostatic discharge)
How do you measure EMC?
no way to measure
man made or naturally occurring
Natural sources of EMI include
Man made sources of EMI include
Three distingushed types of ESD
-Discharge through a spark in the air
-Radiated effects of ESD
Levels of immunity -
Contact / 2 / 4kV
Contact / 4 / 8kV
Air / 2 / 4kV
Q: What is the voltage level in a L2 contact discharge?
Two types of of unwanted signals on cable in an EMI event:
-Differential mode (DM)
CM unwanted signals usually ________.
To successfully filter both types of unwanted signal, a ____________ is preferred.
For DM unwanted signal mitigation, individual _______ can be installed
CM unwanted signal on cabling can
lock up computer
DM noise affects equipment by
corrupting transmitted signals on a balanced circuit
For branch circuits of 5 kVA or less ____________ should be necessary.
Table 2.6 VERY VERY IMPORTANT - Min seperation distances:
-Unshielded power lines or electrical equipment close to open or nonmetal pathways
-Unshielded power lines or electrical equipment close to grounded metal conduit pathway
-Power lines enlcosed in a grounded metal conduit in proximity to a grounded metal conduit pathway
-Electrical motors & transformers
47" or 48"
A min. common-mode rejection ratio (CMRR) of _____ is desirable for high-quality chokes over the operating frequency range of interest.
Three major components of the electromagnetically induced interference problem
-Induced electronmagnetic fields from the electrical power system
-Coupling between the electrical power & telecom system
-Susceptibilty of the telecom system
(not unbalanced DM field)