Unable to turn off primary magnetrons

[Rynoth]

Jake, good advice for general grounding, but aren't the magnetrons independent of the battery altogether? I'd think that connecting the p-lead to the body of the mag would be the most foolproof way to ensure the mag can actually be shut down.

[SonexN76ET]

Ryan,

I think the issue is the need for the common ground between the switch and the engine block and then the P lead when the ignition switch is switched to closed (off).

The Aerovee manual says not to put a wire from the P lead to the magnatron body but it does not specify a reason. I assume that is for normal wiring. I do not know if it would cause damage or not.

Please let us know what you find out in your trouble shooting.

Thanks!

Jake

[Rynoth]

The Aerovee manual says not to put a wire from the P lead to the magnatron body but it does not specify a reason. I assume that is for normal wiring. I do not know if it would cause damage or not.

Jake

Electrically I don't see a difference between wiring p lead to mag body versus wiring p lead and mag body to common ground, so I'm thinking it's the most foolproof way to verify I don't have bad mags. Again, I agree with your reasoning for the final setup but at this point I just want to be sure I don't have bad mags, then I can work backwards. Unfortuantely it might be a week or more before I'm back at the hangar, just trying to brainstorm ideas. Essentially, I just want to be sure my mags can actually be killed!

[Klimek]

During the initial few hours of flight testing I noticed upon shut down my engine seemed to continue to run after electronic ignition was off and then the
magnetron turned off. At first I was unsure of what was going on. It got worse and after 10 +- hours I saw the tiny tach (back up) still displaying RPM and the engine continued to
run albeit rough. Contacted Sonex and they sent two new coil assemblies. (magnetrons) Problem solved. there was a few in a bad batch that got shipped out.
I have ground wires going everywhere to avoid the problem of non-grounding magnetrons and stop any radio noise, charging issues, etc.
By adding ground wires to the mounting screws on the mags was one way to be sure they were grounded.
I disconnected the P-leads, ran separate P-lead wires, started the engine and grounded the add on p-lead wiring and the engine continued to run...Proof positive
(to me) they were internally bad. I am by no means an engineer, however if a magnetron is grounded, it should die....
I know some engineer (s) out there is going to find fault with my reasoning and give my heck. "You know, Frank, at -114c with the quark inversion, the nutrinos can
bridge the riparian zone gap and cause a washout of the resistance core and collapse any grounding bridge", yada, yada, yada....
Go ahead. I can take it. ;)
Frank
ONEX090
N197u0T
37.00 hrs

[Rynoth]

Following back up on this, today I ran a chain of ground wires along both magnetron mounting bolts to the engine block, and from there to battery negative. I still could not turn off magnetos using my switch. I then ran an additional wire from the p-leads to engine ground, and the engine still purred like a kitten. Apparently the mags are no good.

[kmacht]

Maybe a silly question but are you sure it's the mags staying on and not the secondary? Any chance the secondary is staying active and that is why the engine won't shut off no matter what you do with the primary?

Keith
#554

[Rynoth]

Keith, I mentioned earlier in this thread that I've eliminated the secondary as a possibility. Today I actually removed the spark plug leads from the top mag to get a sense of how the engine runs on 2 cylinders (in case I was able to actually kill 1 mag I'd know what it would sound like). My secondary ignition is 100% eliminated from this equation, and the secondary timing is still too far off to run on it alone (if I disconnect both mags)

Btw, the engine does run on 1 mag, just not a lot of hp.

[jjbardell]

Didn't read the entire thread but based on the topic you want to call Kerry. He told me today that some of the mags had a fault and don't turn off.

[mike.smith]

My mags are wired: ground -to- switch -to- mags -to- ground. Nothing else.

[Fastcapy]

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