Polarize Generator After Turning Master Switch Off Every Tim

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j3pup
Posts: 190
Joined: Sun Nov 01, 2009 11:53 pm

Polarize Generator After Turning Master Switch Off Every Tim

Post by j3pup »

Has anybody ever experienced having to Polarize the generator After Turning the Master Switch Off Every Time? We just replaced the battery, voltage regulator, generator(rebuilt), and everytime we turn off the master we need to re-polarize or generator doesn't charge. Also my 35amb generator blast tube is not connected to anything. How are the blast tubes usually ran?

Thanks...
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GAHorn
Posts: 21065
Joined: Fri Apr 12, 2002 8:45 pm

Re: Polarize Generator After Turning Master Switch Off Every

Post by GAHorn »

What procedure are you using to repolarize?

The blast tube is normally connected to a 1" sceet or scat hose to ram air pressure obtained from the rear baffle.

Be certain that your blast tube is positioned on your generator so that the cooling tube is not blocked by the web of the brush-end of the generator.

I installed a 1" flange on my aft baffle and routed my scat hose down alongside the oil cooler blast tube with Adel clamps. I'll posts pics when I find them.

See also: http://www.cessna170.org/forums/viewtop ... ose#p29863
click to ENLARGE
click to ENLARGE
In the pic above, notice the screen placed inside the flange prior to the hose installation to preclude bugs, etc..
The hose pictured below is SCEET hose, which has an inner lining to prevent the wire reinforcement from rusting, breaking off and passing thru the generator.
MVC-043S.JPG
MVC-044S.JPG
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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15A
Posts: 220
Joined: Fri Sep 23, 2005 1:03 pm

Re: Polarize Generator After Turning Master Switch Off Every

Post by 15A »

I feel for you!
After replacing my battery, generator and voltage regulator, all was good! For a while. Dam if things didn't change!
How could this be? :? Well, thanks to my AI and friend, they found the broken, shielded field wire going from the generator to the voltage regulator.
The internal wire broke inside the shield where it bent 90 degrees at the firewall 8O . That tid-bit of info cost me a lot of, well, heart-ache :roll:
But these guys found it and fixed it.
So, the answer to your problem is probably right there in front of you. You just haven't seen it yet! :lol:
Joe Craig
'56 C172 Taildragger N6915A
'46 Aeronca Champ N65HM
j3pup
Posts: 190
Joined: Sun Nov 01, 2009 11:53 pm

Re: Polarize Generator After Turning Master Switch Off Every

Post by j3pup »

Thanks all, I will be replacing all the wires, making sure they are 8Gauge as well as checking the fuse. Lets hope this works.
j3pup
Posts: 190
Joined: Sun Nov 01, 2009 11:53 pm

Re: Polarize Generator After Turning Master Switch Off Every

Post by j3pup »

Following all George's recommended tests from the other post, we concluded that the generator although just rebuilt was the culprit. Took it to the shop and they concurred that that the armature was burned out. Awaiting my generator back.... Thanks all
j3pup
Posts: 190
Joined: Sun Nov 01, 2009 11:53 pm

Re: Polarize Generator After Turning Master Switch Off Every

Post by j3pup »

Turns out the generator armature was shorted out, works great with a new armature.
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