Looking for a simple relay that I can use in a circuit to create a brief delay and then reset itself.
The circumstances are as follows; a heavily used automatic door with a prox card entry and a push button exit. The electric strike is fail-safe. The door opener is powered by a pneumatic opener. The problem is that the door sometimes pushes against the strike before it can release. After several adjustments it has been determined the best solution would be a 1 sec delay on the pneumatic opener to give the strike a head start. Any suggestions? Thank-you.

Places like Digikey have a pretty good assortment of time delay relays.

Here is one but it isn't cheap.
http://www.digikey.com/product-deta...ld-relays/CUA-41-70001/PB2153-ND/1127869

Yes, that is a bit pricey.

My boss is hoping I can find something simple and inexpensive as he expects this won't be the last door opener we need to modify.

I have been experimenting with an Omron H3CA since we have several sitting on the shelf which were salvaged from other projects. I can get it to do everything I want except auto reset after the delay.

What about these?

http://www.schneider-electric.us/en...ng-relay---0.1-s..100-h---24-v-ac---2-oc

As Sparky found, you can do better on the price. Digikey is like Grainger. They have everything but you pay for the convenience. Once you figure out what you need, the internet is your friend. A lot of this stuff shows up on Ebay pretty cheap.

Hi potseal, what do you mean with auto-reset?

You have your control voltage going to "high", after one second the relay should activate, and when the control voltage goes back to low the relay instantly should go off?
That's the basic "on-delay" type.
You can get this from your omron device by connecting term. 3+6 and using mode A.
If you only want a short impules from the relay, you Need mode F.
See the Manual here
http://www.farnell.com/datasheets/1500432.pdf

I don't know what distributors and relay manufacturers you use. In europe, I would go to farnell or RS Website and look for omron, tele, ABB, panasonic, eaton, finder... din-rail mount relays. They start at 40 bucks. Watch for UL or other markings you need for the US.

One second is long to wait for an automatic door, I would recommend an adjustable relay. Maybe it will work fine with 0.2-0.5 sec only.

This might work

https://www.grainger.com/product/ICM-Relay-4E233?s_pp=false&=

"Auto reset" refers to the ability to reset itself after it performs it's function. For the Omron H3CA in A mode it appears I would need a manual reset or power loss to reset it. There is another mode that uses a time-limit reset. Unfortunately that function appears to be for off delay only.

I seen that one before. The price is appealing but it has a minimum 1.8 sec setting. A little too long for our purpose.

I need to post a wiring diagram. That relay and the Omron I've been using might both work but I might not be placing it in the circuit correctly. The basics are that if either the exit or entrance momentary control is utilized a relay closes and powers a solid state relay which in turn opens the circuit for the strike (fail safe) and closes the circuit for the pneumatic control. I need to delay the pneumatic just brief enough that the strike can't get stuck closed by the door pushing on it before it releases.
I know where the delay is required and can envision how everything is wired except for how to reset the Omron (or other relay).

Well yes, the omron will reset on power loss (respectively: input loss) in mode A.
But don't you get that necessary power loss from the existing System?
Some time after opening the door, the existing relay and solid state relay will power off again, won't they?

How about

https://www.automationdirect.com/adc/Shopping/Catalog/Process_Control_-a-_Measurement/Timer_Relays_-z-_Counters_-z-_Tachometers/Fuji_Electric_Timer_Relays_Mini-DIN_(ST7_Series)/ST7P-2A15S-ADC

A second sounds a long time for the latch to operate. Stuff like that I've encountered has been more like a tenth of a second.
Assuming its a DC system, perhaps you could arrange your own simple delay circuit with a basic relay, a capacitor, and maybe a resistor.
(Sorry I don't know how to put diagrams on here, but -)
Break the line to the pneumatic solenoid and take it through the relay N/O contact. Connect a capacitor across the relay coil. Supply the relay coil/capacitor via a resistor. A bit of bench experiment would be the easiest way to determine resistor capacitor values.

Sorry for not posting back sooner.

As I suspected I had the right relay but I was looking in the wrong location as to where I should place it. In the end I used the Omron H3CA relay. When either the prox card entry or push button exit is activated a signal is sent to the pneumatic control board which in turn powers the 120 VAC air actuator and door strike N.C. relay. This is where I placed the delay. Like Geoff and andey stated 1 second is too long. I set the Omron for a 0.5 sec. delay between the pneumatic control board and the air actuator and it appears to be working perfectly. Previously we had the pressure turned down to keep the door strike from jamming which prevented it from opening a full 90 degrees. Now the pressure is back up and the door is opening to a full 90.