9 - Suppressing electro-mechanical devices

Provides 0.5 hour towards CPD

Read more about CPD with EMC Standards

9 - Suppressing electro-mechanical devices image #1

***Updated for 2019***

This module helps engineers to understand that when a contact opens the current can’t change instantly because of the inductance in the circuit

– inductive energy is stored in any conductor (e.g. mains supply distribution and long DC cables)

– also stored in all coils and windings (solenoids, transformers, motor windings, etc.)

 The resulting voltage flyback breaks down the contact’s air gap while it tries to maintain the current flow. The frequency spectrum of arcs and sparks is truly ‘DC - daylight’ and this wide spectrum is radiated (or picked-up) by all conductors depending on their length and resonant frequencies.

Course is 35 slides over 18 pages


1) Emissions caused by arcs and sparks

2) Suppressing electromechanical contacts

3) Suppressing the flyback from switched inductive loads

4) Suppressing commutator motors

5) Suppressing slip-rings

6) Suppressing spark ignition

7) Suppressing electric bells and buzzers

8) Some useful references 


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