Automatic 2 second 240v mains interruption using relays - how?

Submitted by Tom Smith on

Hi guys and gals

Absolute beginner here doing a small project at home. I require the following functionality for an aspect of my project:-

Constant power to a device at all times (240v supply) with a momentary button that disconnects the supply circuit for 2 seconds and restores it automatically.

I was thinking a normally closed relay that when triggered, opens, stays open for 2 seconds, then closes again. How can I achieve this?  It needs to be 1 button press with the 2 second hold and then the close happening automatically in a sequence. Not sure if I require 2 relays with delays to achieve this and how I'd wire it up, or wether there's an off the shelf solution? Any help greatly appreciated. 

Many thanks in advance

Tom

Hi Tom, for this you can use a 555 timer circuit along with a relay.When you push the button that activates the 555 timer which will trigger the relay.After a certain time, it will again restored.Hope it helps!!!

  Joined August 22, 2019      125
Thursday at 12:29 PM

You can also use RC time constant and a transistor to achieve this one.

  Joined February 12, 2018      696
Monday at 02:11 PM

Hi Tom Smith! There are various methodologies you can adopt to complete your project. First you can make a RC circuit according to which you can set your required time (i.e., t = R*C) for disconnection. Also, you can use a commonly used IC NE555 by using which you can set the frequency/time in any of its 3 modes. And the smart way for this is you can use a micro-controller by using which you can set a condition for the relay to activate and deactivate the supply connection. You can use any of the above methods.

  Joined April 09, 2020      55
Thursday at 02:40 PM