Spark suppression

[Catnamedog]

Hi
I've just joined the forum. This is my first post, so I apologise if its in the wrong place.

I'm building a bottle-filling machine, and am using a 12V DC relay to switch 220V AC mains across a 1.5A rating n/o relay contact. It will operate a 220V AC solenoid valve of around 1A.
The relay draws about 0.5A, and is operated by a liquid level float reed relay switch.

Can anyone advise me on the value and composition of the 2 spark-suppression capacitors I will need across both the relay contact and the reed relay contact?

If you're interested, I could publish the circuit diagram I 've drawn up for the machine. Its very simple.

 

[Catnamedog]

Sorry, I meant to say thank you in advance!

 

[Diver300]

The best suppressor across the DC relay is a diode, in reverse so that it takes no current when the coil is energised.

A capacitor of about 0.1 uF would be OK for the AC solenoid. It should be rated to 500 V DC or more, and it is a good idea to put 100 - 500 ohms in series with the capacitor, to limit the inrush current into the capacitor.

 

[crutschow]

How about using a zero-crossing solid-state relay to power the solenoid. It would be much longer lasting then a relay and you wouldn't have to add any suppression circuits to either device.

 

[Catnamedog]

Thanks a lot.