Main power/starter relay failed?

[joea]

Well folks, I guess that 66 years is all we can expect on the main battery relay that shuttles power to the cockpit and starter!!!

Been thinking that I had a bad battery but just tested that and its ok.

Has anyone ever swapped out their relay in a Sedan? Am finding out that we believe that its not a normal "positive 12 volt" triggered relay but something called a "Ground Activated Circuit" relay. Evidently Aeronca uses the cockpit master switch to complete a ground which then closes the relay and supplies power to the airplane.

Anyone have any idea where to get one of these critters?

Thx,

Joe A

[Paul Agaliotis]

Joe,
You should be able to replace the relay with any quality relay. There should be a master relay, and with a key starter, a start relay. The master relay should be a continuous duty type. I have seen some with dual small ring terminals to activate. One side must be grounded. The single lug style will have the second connection internally. You should be able to find one from ACS.
Paul

[joea]

Joe,
You should be able to replace the relay with any quality relay. There should be a master relay, and with a key starter, a start relay. The master relay should be a continuous duty type. I have seen some with dual small ring terminals to activate. One side must be grounded. The single lug style will have the second connection internally. You should be able to find one from ACS.
Paul

Paul,

Thanks and we tried that and had several generic relays around the hangar. All of them were activated by 12+ volts.

Evidently the Sedan relay is activated by grounding the "trigger post" on the relay. It goes through the master switch that completes the ground on the circuit that pulls the relay closed.

Ever seen one like this? I sure have not!

Thx,

Joe A

[Paul Agaliotis]

Joe,
You will need a relay with two small ring terminals. This style uses the terminals to control the coil wires. You can ground one side and power the other, or power one side and ground the other. Kind of like the Ford starter relay.
Paul

[joea]

Paul,

Thanks and that was the 2nd one we tried!

First attempt was a single trigger post relay that works with power to the trigger post. No luck as the Sedan's wire from the master does not trigger using 12 positive.

Next we tried a double trigger post relay and ran one wire from one of the trigger posts to ground (via its mounting bolt on firewall) then the Sedan's "trigger wire" to the 2nd post. Still no luck, then we went to the schematic and Gareth Gilson (Sedan #068) said that its triggered using a ground and not power, and we were dead in the water...

Hmm you just made me think... we could have run the "external extra wire" from the battery side post one of the trigger posts to "power" the relay, then run the "trigger wire" from the master switch to the second trigger post, and use that as the grounding wire. We did not try wiring it up that way, as we were kinda tired and it was getting chilly so the thought processes not the most active.

Think that might work?

Thx,

Joe A

[Paul Agaliotis]

Joe,
Yes,I think that should work. It's just a coil of wire inside that little thing, so the switch can be on either side of the coil.
Paul

[MikeB]

I was going to suggest the (ahem) Ford relay which has two open (insulated) posts for the coil and you simply "hot" one and "ground " the other through the switch but I'm sure there are others more suited. In fact, I think the one I have on my L16 has two insulated posts.
Mike

[joea]

I was going to suggest the (ahem) Ford relay which has two open (insulated) posts for the coil and you simply "hot" one and "ground " the other through the switch but I'm sure there are others more suited. In fact, I think the one I have on my L16 has two insulated posts.
Mike

Thanks to both of you guys and will give it a try!

Joe A

[Matt]

Joe,

Let me know, if it worked out. Otherwise, I will check what type of relay I have in N1331H, next time I am at the hangar.

Matt

[joea]

Thanks and we have it worked out now. Just takes a relay that can be triggered by a negative (grounding) signal.

Joe