Delay-Off relay

[peace brainerd]

Can anyone make a recommendation?

Need to trigger 120vac (no more than 6amp loads) with 12 or 24vdc, and have the OFF delay by up to 60 seconds.

The closest I could get out of Digi-key is two units combined for over 100 dollars. I have found relay off-delay timers on ebay for less than ten bucks. But I'm not familair enough with relays to know what to look for.

For instance, used in conjunction with a std 24vdc/120vac relay, would this be fine?
http://cgi.ebay.com/SQUARE-D-9050-J...sPageNameZWD1VQQcmdZViewItem#ebayphotohosting

This next one seems perfect 3 to 300 seconds. 24vdc in, 120vac out. Am I on the right track?
http://cgi.ebay.com/New-NIB-ATC-Tim...ryZ42897QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

There are many "off delay" relays available, but I notice that some off these are only "egg timers" with terminals - for manually delaying time off with a knob, like on a coffee machine.

I need a timer/relay that will automatically continue to deliver 120vac for as long as a minute after the 24vdc signal is switched off.

thanks for any advice.

 

[AndrewT]

Hi,
a standard mains relay with low voltage coil powered from the mains side would do.

Then put in a 555 timer to monitor the on/off signal and keep the relay closed until the timer goes off.

 

[Nordic]

Was just going to say, you need $2 worth of components to make one...

 

[sklimek]

If you like the old look the Amperite relay/delay tubes are very cool. they can switch 6V up to 115V and come with normally open/closed as well as different time delay settings. Ebay sells them as well as Tubes and More, AZ, cheap too. I think Amperite also makes ss as well. This pdf shows how to order/find the correct one.

http://www.amperite.com/Uploads/g.PDF

 

[peace brainerd]

I don't have very much depth in electronic skills (at least compared to what is typical here at diyaudio). I create a lot of things, but my projects are by necessity more macro engineered than micro - a variable (off) time 24vdc/120vac relay is pretty much a "black box" utility for me.

The second link that I posted would be just perfect, except that upon closer examination, it's only 120vac input. Now I can stick a std 12/120 relay upstream of this, but now It's getting messily complicated and expensive again.

Any chance that there is a circuit diagram on the net for a small component-count method of doing this? I'd like to make it knob adjustable to about two minutes ideally.

Thanks so much for the suggestions.

 

[BWRX]

Check out page 9 of the TI 555 timer datasheet.

The values of Ra and the capacitor determine the time constant and thus the delay.

http://focus.ti.com/lit/ds/symlink/na555.pdf

 

[gmphadte]

CD4541
This ic is intended for this application in particular.
It has a auto power-on reset, and also needs small cap.

Gajanan Phadte

 

[peace brainerd]

I found it!!

(..and that was a bumper sticker in the seventies -- man I wish the rapture would just hurry up and deliver some of these idiots)

http://cgi.ebay.com/DAYTON-6A855-TI...4399929QQihZ001QQcategoryZ78208QQcmdZViewItem

(and he didn't even try to bend me over the couch for the shipping costs!)

I did say that this was "black box" engineering for me. And this is a heck of a black box for anyone interested in monkeying with this sort of thing. Use the right little SS relay and you could combine this with just about anything to control a circuit.

Anyway, thanks for the help here.