Jastech EMC Consulting LLC

Cost Effective EMI Suppression Techniques for DC Motors

Seminar Outline


Automotive EMC requirements
EMC terminology
Electromagnetic noise sources
E–field coupling
H–field coupling

Grounding Principles

Low frequency ground
High frequency ground
Hybrid grounds

Components used for suppression

Ring varistor
Ferrite beads
Brush material

Different Types of Filters

Common mode
Differential mode

Motors & Relays

Transient suppression for inductive loads
RF suppression for inductive loads

Antennas in EMC

Antenna types
Radiation due to accelerated charges
Motor parts which act like antennas


Shielding effectiveness
Absorption loss
Reflection loss
Grounding of shields
Motor housing
•Rolled steel
•Drawn steel

Simple Measurement Techniques