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News-Blog - Solid State Relays

SON(with Low Electromagnetic Noise Emission)

celduc® relais has just launched a new range of EMC optimized Solid State Relays (with low electromagnetic emission – low RFI) : « SON » range. These relays are particularly suitable for applications where electromagnetic noise must be limited (household and electrical appliances, information technology and medical equipment).

You can find standard « low noise » SSR on the market but those are limited to low switching current of 5A for domestic applications or to low inductive loads, while lots of pure resistive loads applications have high emission noise.

Our new EMC optimized SON range meets these requirements (Conducted emission noise level < 66dBµV) and can control class B appliances on pure resistive loads.

Part Nr :
SON845040 (40-275VAC – 50A – Ctrl 6-32VDC)
SON865040 (50-500VAC – 50A – Ctrl 5-32VDC)
Current limits : 40A @ 220V / 27A @ 400V

What’s EMC directive ?

There are two kinds of appliances:
-Class A appliances designed for industrial environments,
-Class B appliances designed for domestic use.

as well as two kinds of emissions:

courbe1_low_noise-Radiated emissions: low with our standard Solid State Relays,
-Conducted emission noise: with standard Solid State Relays, conducted emission noise is emitted by thyristors and at 150KHz you reach the highest level.

 

According to the application, applicable European standards are different.
Here are the main European standards for Electromagnetic Compatibility (EMC) :normes_cem_uk

For celduc, the major EN standards for Low Electromagnetic Noise Emission are EN55022, EN55011 and EN55014 which represent the main categories for electrical appliances.

Class A Radiated Emissions Limit:
classea_uk
 Class B Radiated Emissions Limit :

classeb_uk

At 150Khertz the emitted noise at Quasi-Peak shouldn’t exceed:

-79dBµV for class A appliances
-66dBµV for class B appliances

Example of conducted emission noise level for a standard Solid State Relay used to control a resistive load AC-51 8.6A @ 400VAC.
Tests performed in compliance with EN 55014 in quasi-peak.

We record 78dBµV @ 150Kherts which is acceptable for an industrial application, but not for a domestic use as we are over the limits of 66dBµV.

courbe2_low_noise

Same test performed with our new SON Solid State Relay EMC optimized :

We record a conducted emission noise level of 56dbµV @ 150Khz which is < 66dBmicroV

courbe3_low_noise

You can find standard « low noise » SSR on the market but those are limited to low switching current of 5A for domestic applications or to low inductive loads, while lots of pure resistive loads applications have high emission noise.

Our new EMC optimized SON range meets these requirements (Conducted emission noise level < 66dBµV) and can control class B appliances on pure resistive loads.

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