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-   -   Magneto /Ignition Switch connection clarification (https://vansairforce.net/community/showthread.php?t=201383)

osaleh 11-25-2021 10:37 AM

Magneto /Ignition Switch connection clarification
 
Good morning folks and happy thanksgiving.

Can you please give me some guidance here. I have my slick mags that i ordered with my lycoming 4 cylinder 0-360 carb engine. From what I have read till now, i will need to connect the p-leads from each slick mag to the R and L tabs on the switch. The switch I have is A-510-2 ignition switch. I also need to use shielded wire. please see questions below:

1) Do I use a 20 ga 1 cable shielded wire for each mag or do I need an 18 ga 1 cable shielded wire? I plan to use the shield as the second wire for grounding

2) Do I need to connect the shield to both ends? that is do I need to connect one end of the shield to the magneto and the other end of the shield to the ground tab on my switch? in effect turning my 1 cable shielded wire to two cable shield wire, one wire connecting to p-lead on mag and switch and the shield wire connecting on mag ground and switch ground.

thank you

azrv6 11-25-2021 11:06 AM

1 Attachment(s)
Wiring diagram Z-26 of Bob Nuckolls Aeroelectric Connection has a detailed diagram for wiring the Gerdes A-501-2 switch including wire gauge and how to handle the grounding and the shields. You can download a pdf of the book for free.

Here is a screen grab of the diagram:

Attachment 18720

BobTurner 11-25-2021 01:16 PM

Above post shows diagram. Yes, shield to proper terminals on both ends, the shield acts as a conductor in this application. You didnít ask, but also note the jumpers installed on the switch - they need to conform to your type mags (as shown, for left impulse, right non-impulse). Also make sure the wires are supported to minimize flexing, especially at the crimps. I once nearly killed myself after a P lead broke right at the connector.

PilotjohnS 11-25-2021 02:28 PM

Note
 
Please note, as I mentioned in another post, the GRD on the switch does not have a connection to the aircraft structure ground. You do not want the aircraft structure ground connected to this circuit. At the magneto, the ground for this wire will be hooked to the engine case ground automatically. This way, the mag shield does not carry any current between the aircraft structure and engine case, only mag current. Just follow the diagram and you will be fine.

Draker 11-25-2021 06:52 PM

Quote:

Originally Posted by BobTurner (Post 1571086)
Above post shows diagram. Yes, shield to proper terminals on both ends, the shield acts as a conductor in this application. You didnít ask, but also note the jumpers installed on the switch - they need to conform to your type mags (as shown, for left impulse, right non-impulse). Also make sure the wires are supported to minimize flexing, especially at the crimps. I once nearly killed myself after a P lead broke right at the connector.

Here's what I think is a pretty nice way to secure the wires on the magneto side. Learned it here on VAF:


osaleh 11-26-2021 07:27 AM

Thank you Dave. I am using the slick magnito model 4373. No electronic ignition. I think i am clear on the diagram but do not understand the jumper wire. So i install a jumper wire from right terminal to GND terminal? This configuration is for one Non Impulse coupled magneto and one electronic ignition. I am not sure i have this configuration. so question is , do i just follow the diagram as is as far as installing the jumper?

lr172 11-26-2021 08:45 AM

Quote:

Originally Posted by osaleh (Post 1571162)
Thank you Dave. I am using the slick magnito model 4373. No electronic ignition. I think i am clear on the diagram but do not understand the jumper wire. So i install a jumper wire from right terminal to GND terminal? This configuration is for one Non Impulse coupled magneto and one electronic ignition. I am not sure i have this configuration. so question is , do i just follow the diagram as is as far as installing the jumper?

If wired according to the above diagram, the switch will only allow the left mag to fire with the key in the S position. It is critical that you use the specific grd posts shown.

DanH 11-26-2021 09:11 AM

1 Attachment(s)
Quote:

Originally Posted by BobTurner (Post 1571086)
Also make sure the wires are supported to minimize flexing, especially at the crimps. I once nearly killed myself after a P lead broke right at the connector.

Yes please, and me too. Classic case...A-65 Continental, somebody moved the prop just a little, the impulse clicked, and thankfully the three or four revs missed all the guys clustered around the nose.
.

BobTurner 11-26-2021 12:47 PM

Quote:

Originally Posted by osaleh (Post 1571162)
Thank you Dave. I am using the slick magnito model 4373. No electronic ignition. I think i am clear on the diagram but do not understand the jumper wire. So i install a jumper wire from right terminal to GND terminal? This configuration is for one Non Impulse coupled magneto and one electronic ignition. I am not sure i have this configuration. so question is , do i just follow the diagram as is as far as installing the jumper?

The diagram shows the connections when using an impulse mag on the left, and a non-impulse mag on the right. The jumper disables the right mag on starting. If you are using two impulse mags (as it appears you are) then you want both enabled for start - no jumpers.

osaleh 11-27-2021 05:14 PM

Thank you all folks . Inquiry cleared . It seems I have the same magnetos as diagram so will follow that .


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