Controlling the relay - When

[FreshmanNewbie]

I have an AC circuit where I have a relay which I will be controlling.

Is it OK if I turn ON the relay an any time during the AC 50Hz cycle? Or what are the advantages of turning on the relay at zero crossing of the AC signal using a ZCD?

Can someone tell me the advantages with using ZCD and what problems I may face if I don't use ZCD and turn the relay ON at variable times of AC input?

 

[betwixt]

If you are meaning a mechanical relay, there is little point in trying to match zero crossing because the time taken by the mechanism isn't that well defined or repeatable.
For a solid state relay there may be an advantage because switching will occur at low voltage and avoid sudden current spikes and the interference they may cause.

Brian.

 

[KlausST]

Hi,

I guess you are talking about a mechanical relay.
Can you give any link to a site where the zero cross switching of a realy is discussed?
Or: Where is your idea form?

Klaus

 

[andre_luis]

Or what are the advantages of turning on the relay at zero crossing of the AC signal

You didn't mention the load, whether it is well known or if can be of any kind. In the case of inductive ones ( e.g motors ), they will try to keep pushing the current even during the relay contact opening transiction, creating spikes; this is why a zero cross approach is desirable.