PA-22-150 Master Switch

[Steve Pierce]

Jared- 30 amp. W31 The alternator is a Denso 40 amp. controlled to 30 amps by a 3 amp. field circuit breaker. The 337s are on Andy Anderson's site. Homer came up with the idea and got the original approval and then i copied it and also got it on a field approval. Works great.

Actually a gentleman with a Colt was the originator of the Denso alternator installation. Homer did a nice job of documenting the installation for the Form 337 and sharing that data.

[Justin Christensen]

IMG_5675.jpg

Why on my master switch there are a bridge between the two sides. In the picture I drew red marks where they are bridged together. Do some switches have an internal bridge? This was connected to a system with the interav alternator but I am going back to the old generator wiring. Should I take off the bridges?


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[Justin Christensen]

IMG_5714.jpg


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[deandayton]

Justin,

The images you posted are to small to read.

The original system had 2 fuses. One for the switch up position and one for the switch down position. Did someone install a single circuit breaker instead of the fuses in your plane? This may or may not have been done as part of the alternator upgrade...

When in doubt, talk to the IA that is going to sign off on your electrical system change.

Dean

[Jim Hann]

Same as Dean, I can't really see your pictures due to the size. However, when I was working on my airplane a while back I found that my fuses had been completely bypassed in the box! Trace your wires, they should each go to a separate fuse and then onward into the system (I can't remember how they come back together.) I'm taking a wild guess here but I'll bet somebody in the past decided your airplane didn't need a main and a backup fuse! (I hope my sarcasm comes through.) My airplane now has the Svenn's lightweight batter and circuit breaker master switch so I removed all of the double circuitry in the box under the seat.

Good luck.

Jim

[smcnutt]

Nothing useful to add but I can't see the pictures Justin posted at all. Just some kind of graphic that looks like a piece of paper torn in half. I'm using the shortwing app so maybe that is the problem. I can see pictures in other threads but just not the ones in here.

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[Justin Christensen]

IMG_0390.jpg

Not sure why those pictures weren't working. I'll try this one. I can't wrap my head around why anyone would bridge the two sides together. I drew lines where there is a bridge. Sorry I haven't been able to take a picture of the actual switch in the plane. There are 2 fuses connected. But another weird thing is there is a wire that goes directly from the master switch to the landing and taxi lights. That doesn't look right either from the piper drawings. I plan on taking the bridges off and wiring according to the drawings


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[Steve Pierce]

The whole point in the original switch and two fuses is you have 2 chances, if you happen to blow the fuse the first time you turn the master on you can throw the switch the other way and have one more chance before having to install a new fuse and figure out why it blew.

[Justin Christensen]

Steve I understand that concept, but why would one bridge the two sides together like in the picture? It is also wired to two fuses


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[Steve Pierce]

I quit asking why people do the things they do, hurts my head. Sometimes they think they know more than the people who designed and built it.