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  #1  
Unread 09-14-16, 11:07 AM
JB78382 JB78382 is offline
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1965 alternator switch

The split rocker switch that controls the alternator allows the front alternator to be taken off line, and leave the rear alternator on line. However, it does not seem to allow the reciprocal function ( turn off the rear alternator and leave the front alternator on line) . Instead the right (rear) alternator switch turns both alternators off.

Any ideas on why this is?

Cheers!

Jerry
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  #2  
Unread 09-14-16, 10:43 PM
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hharney hharney is offline
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Is the rear alternator going off line because of over voltage?
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Herb R Harney
1968 337C

Flying the same Skymaster for 47 years
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  #3  
Unread 09-15-16, 10:23 AM
JB78382 JB78382 is offline
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Alternator switch

No, the rear alternator is doing just fine. The "Standby/Run" switch worked as advertised. The front alternator fell apart (literally) during approach to destination. I had not paid the alternator switch any real attention until then. I have now had my attention refocused.

During pre-flight run up I have a set of toggles and meters that measure either battery or alternator levels of charge/discharge, as long as the needles said charging and the load was equal, I was a happy guy. We didn't get into the mechanics of the actual alternator switches until it came time to shut stuff down.

At my maintenance base (KRBD) there are 4 vintage 1974/6 337s. I looked at each of those and my set up is very different from them. The other 337 are all either P337 or T337s with 38 amp or more alternators.


Jerry
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  #4  
Unread 10-17-16, 05:07 PM
DrDave DrDave is offline
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Jerry:

What is the serial number of your plane? I will look at the wiring diagram.

Dave
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  #5  
Unread 10-17-16, 07:41 PM
Kim Geyer Kim Geyer is offline
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I know just what you are talking about. Just got 4 new switches today and you can turn them both on, but can only turn the fwd one off but not just the rear without turning the fwd off too. I can see an easy fix by removing a small tab between the 2 switches
I plan to call Cessna and tell them about their blunder.
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  #6  
Unread 10-18-16, 03:01 PM
JAG JAG is offline
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Cessna reason?

It would seem Cessna had a reason for this - but I can't think of it. You have me wondering about my '66 now. Will check it on the weekend.

Jeff
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  #7  
Unread 07-24-17, 10:21 PM
JAG JAG is offline
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Follow up

Sorry for the delayed follow up. My '66 (337-0487) alternator switch can switch both on or off independently.

Jeff
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  #8  
Unread 07-25-17, 08:41 AM
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1965 alternator switch

Hello. I have the same type switch for my MASTER on my 69 C172. The left side (Alternator) right (Battery) you can switch on the battery independently but with both on you try to turn off just alternator side both go off. I was wondering where the "TAB" is you are talking about removing? I'd like to do this modification as well??
BILLS
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  #9  
Unread 05-28-19, 07:25 PM
DABULLY82 DABULLY82 is offline
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I think you could have a fuel pump switch instead alternator switch, cause the way you describe it works is as a fuel pump switch
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  #10  
Unread 05-31-19, 11:34 AM
Kim Geyer Kim Geyer is offline
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My fuel pump switches are red and yellow. alternator switch is grey
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