one shot timer

Apr 10, 2010 4 Replies

Is a switch available that will sense a 240V supply (to a fan) has been switched and then itself switch a separate 240V supply (to a 230W resistance heater) for 15 minutes and then switch off and not reset until the original supply to the fan is off again?



AJH


Possible not a switch in the sense of something you mount on the wall but there will be relay based modules that should do it but normally from the same supply. An industrial time delay relay will be expensive but likely to have more options such as separate sensing and load circuits

Look at RS, Farnell and maybe CPC

Bob

The logic circuit is called a non-retriggerable one-shot or non-retriggerable monostable.

Crouzet Chronos 2. You need "function H" which is timing on energisation.

has the MUR1 at about a third of the usual price and also the MBR described as single shot. They also look as if they could answer questions on it!

MUR 1 Data sheet

I searched on the terms Andrew G gave and only found 12V circuits, your off the shelf 240V one fits the bill so I have ordered this and a 240V relay to strap across the fan terminals.

Thanks Peter I would normally have 'phoned after posting here first to give the others a chance :-)

AJH

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