Linear Actuator to Reverse when power is off

[Forcedfed]

I may be over thinking this, but here is what I'm trying to do.. forgive me if it has been addressed before, I have been looking around like crazy and haven't seen anything quite like what I need..

Its simple.. I want my linear actuator to extend to its limit (it has internal limit switches) when the relay gets triggered and when that trigger is turned off, the actuator would retract fully to its limit and stop.

It is a 2 wire actuator.. wired one way it extends, reverse the wires and it retracts. I have a DPDT relay and several "normal" automotive relays if needed. I don't want a rocker switch, just trying to open up my headlight doors when the headlight switch is pulled and shut the doors when it's off.

Here is a pic of the relay I have..Thanks in advance!

[pebe]

Here you go.
A is the actuator. The two switches shown are the extend-retract limit switches. V- and V+ are the power supply.

(Edit 15/08/13: Faulty diagram removed)

[Forcedfed]

Wow.. You make it look simple! I really appreciate your help, I'll mock it up tonight and see if I can't light myself on fire in the process! Thank you again!

[pebe]

Sorry. There is a mistake in the diagram. The actuator is in the wrong place! I'll correct it tomorrow.

[Forcedfed]

O.K.. Thanks again.. I mocked it up and it powered up and stopped like it was supposed to, but I still had to physically reverse the + and - wires to get it to retract.

Whenever you get time..

Thanks!

[pebe]

Here is the corrected diagram. You said the actuator stops where it should with the diagram I first supplied, so it would appear that the limit switches are built-in - ie. there only two wires available. If so, wire it up like this. If the limit switches are separate, fit them where shown at X. If it then doesn’t work, transpose the switches.

Best of luck.

[Forcedfed]

Hmm.. This setup does the same thing... In mock up, I hook up + and - and it opens like it should. I would think that removing either the + or - would simulate the headlight switch being turned off and trigger the actuator to retract, but it doesn't.. I still have to manually reverse the wires to get it to retract..

And you are right, it is a simple 2-wire actuator with internal limit switches.

[pebe]

It seems like the coil is not pulling the relay in. Could you post a diagram of how the coil, lamp and operating switch are wired up?

[Forcedfed]

OK.. I'll send some pics when I get home.. When you say coil, are you talking about pins 7 and 8?.. I don't have those hooked to anything.

[pebe]

That's your problem. You need those pins wired across the lamp so that when you switch on the lamp the coil is energized and the actuator extends. When the lamp is turned off the coil de-energizes and the other set of contacts make and reverse the actuator.

[Forcedfed]

Made sense but it didn't work! I took pics and started labeling it to post, but I had to leave.. I'll post it it the AM, sorry its been such a PITA!

The V+ and V- are clipped right to the battery posts (+ and -), pins 7 and 8 are now tied together and were hooked to the headlight wire that gets hot when I pull the headlight switch on which I figure would power up the coil, the actuator is wired like the diagram. I can make the actuator move by switching the 2 wires back and forth on the battery itself.. Pics will be up tomorrow..

[Forcedfed]

Here it is..

[pebe]

Here is how to wire it up.

[Forcedfed]

Yes! That's better... Works now!

Thanks again for your help.. I'll hard wire everything, reconnect the linkage and post pics (or a video if it lets me) of the finished product. It's a 65 Buick Riviera that's been completely re-done.. Just waiting for my paint guy!

Getting the clamshell headlights to work again was a big deal!

Thanks a million!

[Forcedfed]

Side question.. When I shut the power off, is it left over electricity from that coil that powers the actuator? The reason I ask is that particular limit switch is finicky. Sometimes it gets tied up and never triggers the switch. Since the power is off, will that coil run out of juice or should I readjust that limit switch?