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  #1  
Unread 02-04-05, 03:25 PM
STEFAN CEGIELSK STEFAN CEGIELSK is offline
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Question alternator dischare warning lights

I have had the rear engine alterntor discharge light flickering during flight.It seems to be only on light loads.My engineer says that its a common problem.The alternators seem to be charging correctly.When a heavier load is put on ie.Pitot heat then the light goes out.Has anyone experienced the same problem?

C337
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  #2  
Unread 02-04-05, 05:00 PM
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Ernie Martin Ernie Martin is offline
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I'm not an expert, and others may want to add to this, but I understand that the regulator(s) balance the load between the alternators. The service manual (your mechanic has one for your aircraft, right?) has clear instructions on adjusting the system for proper balancing. I don't think that you are at risk of damaging anything running a moderately unbalanced system, but it would be a good idea to do the adjustment soon.

One of the most knowledgeable contributors to this Message Board in this technical area is not too far from you, Pete Somers in Yorkshire, UK.

Ernie
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  #3  
Unread 02-04-05, 06:23 PM
rick bell rick bell is offline
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had the sme problem for a long time and over time it became worse. my problem was in the printed circuit board componets started to go bad, (fuse holders, ect along with the borad being cracked) started to make one cycling until it sheared the alt coupling
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  #4  
Unread 02-04-05, 10:27 PM
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Jerry De Santis Jerry De Santis is offline
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Simple Things First

Stefan, Save time and money and try the following simple things first to see if the problem is either the regulator or fuse.

1, Since it is the front engine Alt. light that is the problem, switch the regulator from the rear engine to the front and take the front regulator and put it on the rear. If the flickering travels with the regulator you know it is that regulator. Don't know about the old regulators but the newer units are adjustable.

2, On the pilot side firewall, you will see two fuses. Take the fuses out and clean the saddles they sit in of all crude and replace.

Good Luck
Jerry
N34EC
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  #5  
Unread 02-04-05, 11:26 PM
kevin kevin is offline
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Stefan,

I agree with Jerry's number 2 item (fuses), but respectfully disagree with number 1. I have had this problem a number of times, I think that Ernie's advice was correct. Adjusting the regulators is very easy, and is, I think, the most likely solution. I would do that first. The regulators don't fail very often, but they do get out of adjustment.

Also, it is important that your mechanic adjust them under your typical load. The electrical system on this airplane must have been designed by an intern, and as the wiring and components get old and resistance gets higher, it is common to adjust the regulators for one load level and have them work fine at that level, but have them display the behavior you described for another load level.

You and your mechanic can take your pick from the advice, obviously there is more than one way to skin this cat.

Kevin
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  #6  
Unread 02-05-05, 05:07 AM
Pete Somers Pete Somers is offline
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Stefan

What you need to first is run the rear engine and load the alternator as much as you can and see that it will deliver the max current, ehile measuring the voltage, make sure it keeps around 27.5. However due to the long run of the wiring from the rear eng the voltage is never stable.
How many hours has the alternator done, when was the last time the brushes were checked?


Also check the condition of the wiring to the alternator, even the ring tags get loose on the wire.

As the previous posts, it is very common on this system to have either alternator 'coast' due to load loads and the battery being fully charged, and lalt out lights flickering.

The regulator system on the 'C' model is one regulator for both alternators and a REG1-REG2 switch in the panel ensures that you have a alternate.
There is no balancing system on this system, it relies on good maintenance of the system.

Regards
Pete Somers
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  #7  
Unread 02-05-05, 11:13 AM
kevin kevin is offline
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Oh duh, you are right Pete, I forgot completely about the early models only using one regulator. Sorry Stefan, forget what I wrote about balancing...

Kevin
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  #8  
Unread 02-05-05, 11:33 AM
Pete Somers Pete Somers is offline
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Talking

Keven!
I had to go back to the service manual to confirm the system, to far back in time to remember, brain getting tired!!

See you
Pete
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  #9  
Unread 02-12-05, 06:47 AM
STEFAN CEGIELSK STEFAN CEGIELSK is offline
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Wink

many thanks everyone for this information.It has been extemely useful
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  #10  
Unread 02-15-05, 04:21 AM
sunnysky sunnysky is offline
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In this thread, Ernie Martin mentions Pete Somers. Well, I've known Pete for over twenty years during which time he has always "fixed" all the usual electrical, autopilot and Cessna radio gremlins on my 337. He is really experienced having worked for Northair who wre the largest Cessna dealers in Europe. Sadly, they got taken over and all the "old hands" were made reduntant.
However, Pete still looks after "GH" and is coming down to Biarritz to fix the autopilot next month.
I notice that Pete often offers advice on this site, so all take notice. He really knows his "337s".
Thanks Pete.
Sunnysky.
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  #11  
Unread 02-15-05, 08:52 AM
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Ernie Martin Ernie Martin is offline
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Pete's expertise was evident from his contributions to this forum. We're lucky to have him. Wish he was on this side of the pond.

Ernie
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  #12  
Unread 02-22-05, 01:32 PM
Pete Somers Pete Somers is offline
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Smile

Hey Ernie
Do'nt give me ideas. I may take you up on that one!!
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  #13  
Unread 02-22-05, 06:07 PM
stackj stackj is offline
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Maybe it would be simpler to drain that "little pond" and build a few refueling stops along the way!
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