Table of Contents
Advertisement
104/653
Electromagnetic Compatibility (EMC)
9.3.9 General Measures of Radio Interference Suppression for Relays,
Contactors, Switches, Chokes and Inductive Loads
If, in conjunction with electronic devices and components, inductive loads, such
as chokes, contactors, relays are switched by contacts or semiconductors, ap-
propriate interference suppression has to be provided for them:
By arranging free-wheeling diodes in the case of d.c. operation
●
In the case of a.c. operation, by arranging usual RC interference suppression
●
elements depending on the contactor type, immediately at the inductance
Only the interference suppression element arranged immediately at the induc-
tance does serve this purpose. Otherwise, the emitted noise level is too high
which can affect the function of the electronic system and of the drive.
If possible, mechanical switches and contacts should only be realized as snap
contacts. Contact pressure and contact material must be suited for the corre-
sponding switching current.
Slow-action contacts should be replaced by snap switches or by solid-state
switches, because slow-action contacts strongly bounce and are in an undefined
switching status for a long time which emits electromagnetic waves in the case
of inductive loads. These waves are an especially critical aspect in the case of
manometric or temperature switches.
Bosch Rexroth AG R912005854_Edition 09
Rexroth Frequency Converter EFC x610
Series
Advertisement
Table of Contents
