Special Type Relay 2

[aware]

Hi All,
I am looking for a 12v dc relay that when powered with 12v dc (constant, not instant) will trigger the relay (ie close a circuit) but only for a preset period of time (eg 10 minutes).
In other words, although the 12v dc will power for a long period of time (let's say some hours), the relay will close the circuit only for 10 minutes and the re-open it again (although the 12v dc power will be still there...)

Hope I made it clear enough and best regards
Al

 

[dpc]

Google for time delay relay or timer

 

[gepman]

It sounds as if you want what is called a "one shot" relay. See

http://www.ab.com/en/epub/catalogs/2051089/6270353/3081335/3306065/

which is programmable for different functions and different times.

 

[itsmoked]

"Normally Open, One-Shot"

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[dpc]

It can be done with any time delay relay that has both instantaneous and time delay contacts. Just put the TDO contact in series with an NO instantaneous contact.

Assuming I understood what was wanted....

 

[aware]

Thanks for all input,

The following seems to fit my needs: (Do you reckon the same?)

http://library.abb.com/GLOBAL/SCOT/...5C76EC3048E8525709E006CAB37/$File/KRDSGen.pdf

 

[gepman]

It appears so. Remember that you will need a constant 12VDC (or other level) voltage source to maintain the timing function.

You might want to see if ABB has a multifunction relay equivalent to the A-B 700-FSM (click on the multifunction tab of the link that I gave above). Multifunction relays are good if you think that there is a chance that the timing logic requirement will change.

 

[waross]

The relay that you have selected will fulfil the function that you have described to us.
However the final choice will depend on the application.
Depending on the application you may want to consider how you want the device to respond to a power failure.
And what action you want if the input signal is interrupted? Do you want the timing to stop or continue?
And again if the input is interrupted and re-established, do you want the timing to continue for the balance of the original interval or do you want the timing to reset and start over?
Some times these points are not important. When they are important, choosing a device becomes a challenge.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[gepman]

And don't forget perhaps the most basic requirement of all, that the relay contact rating is sufficient for the load. There was a discussion regarding this issue of DC contact ratings in the following thread:

http://www.eng-tips.com/viewthread.cfm?qid=204694&page=8