Don't throw away your Generator!

[carusoam]

@nosky2high There is a question here (above^^^^), I believe is for you...   ?

I’m just cruising through reading and understanding.  This thread is about seven years old and gets dusted off every now and then...

It May take a decade before nosky returns back this way on his own... so I sent this invite...

Best regards,

-a-

[0TreeLemur]

On 2/5/2011 at 5:03 PM, Jerry 5TJ said:

I just finished the "eternal annual inspection" and test flew the 65C today.  Hurrah!

 

The Saga of the Generator:  

The generator seemed a bit loose so I put that on the squawk list for the annual last fall.  Turned out one of the bracket bolts was loose, so I took out the generator to get at the bolt.  With the generator out, I could see both brackets' holes were egg-shaped, so I took the brackets out and had them welded up so I could drill nice round holes again.  When I took the brackets out I could see the bolts were from the auto parts bin and not from Lycoming, so I bought new bolts with the proper drilled-for-safety-wire heads. 

 

Since the prop replacement about 20 hours ago, I've noticed something new with the generator mount on my C.  When I pull on the generator belt during pre-flight to check its tightness, I hear a new noise.  Pull-thunk.  Not loud.   Looking closer, I see that the upper bracket where it bolts into the crankcase is slipping under the bolt head.   I'm guessing that just like what @Jerry 5TJ observed, it must be egged.  It wouldn't move otherwise.   I guess the increased belt tension associated with removing and reinstalling the belt without loosening the generator mount probably loosened things up a bit.  I think the sound is the generator housing making contact with the front air shield.

This raises questions:

1.  Anything urgent?  It seems that a tiny bit of motion there doesn't likely represent a failure mode.

2.  Aside from welding/re-drilling the hole, does someone sell that part?

3.  What is the max. torque spec on that bolt that goes into the crankcase?   I put a wrench on it and snugged it a bit, but don't want to go too far.   Looked in the SMM and didn't find it.

Thanks,

Fred

[47U]

2 hours ago, 0TreeLemur said:

This raises questions:

1.  Anything urgent?  It seems that a tiny bit of motion there doesn't likely represent a failure mode.

2.  Aside from welding/re-drilling the hole, does someone sell that part?

3.  What is the max. torque spec on that bolt that goes into the crankcase?   I put a wrench on it and snugged it a bit, but don't want to go too far.   Looked in the SMM and didn't find it.

Yes urgent.

I was changing out the prop oil line (per the AD, 10 years ago) and found the aft hole in the generator mount broken.  It had been welded and broke again.  The prop line adel clamp hid the crack.  Dan (LASAR) sold me a new generator mount, much beefier thickness.  

Check the Lycoming manual for case bolt torque specs.  It’d be a bad thing to warp the mating surface and create an oil leak, or worse, induce a crack in the case.

  

[0TreeLemur]

Let me clarify- it isn't one of the bolts on the bottom of the crankcase, it is the top one on the adjustment mount that seems to be a bit egged.  Moves less than 1/32".  This adjustment arm is the part I'm talking about, the same one that I think @Jerry 5TJ had the hole welded and re-drilled.

15 minutes ago, 47U said:

 

 

[RLCarter]

make sure the bolt isn't bottoming out (getting tight) before apply pressure to the bracket, an egg shaped hole shouldn't keep it from tightening down 

[carusoam]

I wonder if @Alan Fox might have that generator bracket in his collection of Mooney parts...
 

O Tree, your graphics skills are awesome... Akin to that guy W. Disney! 

Best regards,

-a-

[0TreeLemur]

12 hours ago, RLCarter said:

make sure the bolt isn't bottoming out (getting tight) before apply pressure to the bracket, an egg shaped hole shouldn't keep it from tightening down 

That is a great point.  Now that you mention it, that might be happening.  I'll give it a look.  Thanks!

[0TreeLemur]

On 10/9/2020 at 11:11 AM, 0TreeLemur said:

That is a great point.  Now that you mention it, that might be happening.  I'll give it a look.  Thanks!

Followup: the bolt was bottoming out.  In the absence of a shorter bolt, I added another washer and it tightened up nicely.  Thanks again @RLCarter.

[TaildraggerPilot]

Enough time has passed now for there to be a proper revival of this generator thread. My 67 E has the generator setup and, quite possibly, an original Delco Remy voltage regulator. The airplane just came out of a painful extended annual (first one with a new owner usually is), and now I’m seeing unpleasant voltage / amp data on the G3X. The aircraft was down for 10 weeks. Before the annual, my generator was pumping out between 13.5 and 14.5 volts in cruise, and the expected 12.3-12.5 at idle on the ground. Now, when I give power to taxi, usually 1000-1200 rpm, I get good output of 12.8-13.5 volts, BUT during full power takeoff, climb and cruise, the volts drop down to 12.3 to 12.4 with a slow battery discharge of -1 to -4 amps. What is even more interesting to me is that on the descent and pattern power settings (constant 2500 RPM, so the generator is still spinning at the same speed), the voltage goes back up into the high 13’s and everything is fine again.  It’s crazy. Anyone have any clue to the culprit? I’m leaning towards the VR at this point and perhaps a swap to a modern solid state regulator will solve this problem.

1) I “flashed” the generator with master on / engine off. Same behavior from the generator before / after  

2) I really don’t want to swap to an alternator right now. The entire aircraft is LED lighting / glass with a really low systems power draw, and the gear & flaps are manual.

 

Edited April 26, 2024 by Taildraggerpilot

[Jerry 5TJ]

1 hour ago, Taildraggerpilot said:

BUT during full power takeoff, climb and cruise, the volts drop down to 12.3 to 12.4 with a slow battery discharge of -1 to -4 amps.

Ah, a fond old topic….from 13 years ago.  

Shooting from the hip here: Perhaps at high load the regulator’s over-current coil is engaged (disconnecting the generator) and you see the battery discharge voltage.  

A solid state regulator will calm down the generator voltage swings and reduce abuse of the battery.  

[Shadrach]

1 hour ago, Taildraggerpilot said:

Enough time has passed now for there to be a proper revival of this generator thread. My 67 E has the generator setup and, quite possibly, an original Delco Remy voltage regulator. The airplane just came out of a painful extended annual (first one with a new owner usually is), and now I’m seeing unpleasant voltage / amp data on the G3X. The aircraft was down for 10 weeks. Before the annual, my generator was pumping out between 13.5 and 14.5 volts in cruise, and the expected 12.3-12.5 at idle on the ground. Now, when I give power to taxi, usually 1000-1200 rpm, I get good output of 12.8-13.5 volts, BUT during full power takeoff, climb and cruise, the volts drop down to 12.3 to 12.4 with a slow battery discharge of -1 to -4 amps. What is even more interesting to me is that on the descent and pattern power settings (constant 2500 RPM, so the generator is still spinning at the same speed), the voltage goes back up into the high 13’s and everything is fine again.  It’s crazy. Anyone have any clue to the culprit? I’m leaning towards the VR at this point and perhaps a swap to a modern solid state regulator will solve this problem.

1) I “flashed” the generator with master on / engine off. Same behavior from the generator before / after  

2) I really don’t want to swap to an alternator right now. The entire aircraft is LED lighting / glass with a really low systems power draw, and the gear & flaps are manual.

 

https://www.aircraftspruce.com/catalog/eppages/gencontunit_g1500n.php

 

^^^^This is the way.

 

 

[Skates97]

37 minutes ago, Shadrach said:

https://www.aircraftspruce.com/catalog/eppages/gencontunit_g1500n.php

 

^^^^This is the way.

 

 

@Taildraggerpilot, I think I have one in my hangar from when I converted to an alternator. Was working fine when I pulled it. I can check when I'm there tomorrow.

[TaildraggerPilot]

1 hour ago, Jerry 5TJ said:

Ah, a fond old topic….from 13 years ago.  

Shooting from the hip here: Perhaps at high load the regulator’s over-current coil is engaged (disconnecting the generator) and you see the battery discharge voltage.  

A solid state regulator will calm down the generator voltage swings and reduce abuse of the battery.  

I think it’s less about load and more about strange / non-normal output during various power / prop settings. The generator produces plenty of volts/amps over 1000 RPM, but only to a point, then it nosedives at higher manifold pressure settings (@2500 RPM) no matter the load. At lower manifold pressure settings (still @2500 RMP) on descent and approach, the output voltage jumps up to normal.  I’ve  never seen anything like it. I’m going to just replace the VR with a solid state PMA and go from there. 

[TaildraggerPilot]

1 hour ago, Skates97 said:

@Taildraggerpilot, I think I have one in my hangar from when I converted to an alternator. Was working fine when I pulled it. I can check when I'm there tomorrow.

It it’s serviceable, I’ll take it off your hands. 

[jamesm]

I use to do it the difficult way if the Generator was outputting the expected voltage. I would take it off and take it to wrecking yard put on their test stand and make sure they know to run it reverse.  and I made sure there was the correct voltage was outputting.  In those days I wasn't flying as frequently so It would loose it's retentivity  "Flash" over time.

 

[N201MKTurbo]

I would burnish the contacts in the regulator. Especially the current limiter (middle) contact.

[TaildraggerPilot]

5 hours ago, jamesm said:

I use to do it the difficult way if the Generator was outputting the expected voltage. I would take it off and take it to wrecking yard put on their test stand and make sure they know to run it reverse.  and I made sure there was the correct voltage was outputting.  In those days I wasn't flying as frequently so It would loose it's retentivity  "Flash" over time.

 

The new, solid state regulators self-flash apparently. 

[Shadrach]

1 hour ago, Taildraggerpilot said:

The new, solid state regulators self-flash apparently. 

I still think about doing an alternator conversion, but only for the weight savings. The Zef controller and generator offer plenty adequate performance at taxi rpm. I have never had to alter my SOP due to charging issues. I think you’ll find the new set up favorable.

[TaildraggerPilot]

43 minutes ago, Shadrach said:

I still think about doing an alternator conversion, but only for the weight savings. The Zef controller and generator offer plenty adequate performance at taxi rpm. I have never had to alter my SOP due to charging issues. I think you’ll find the new set up favorable.

I did an alternator conversion (interav) on my old Comanche 25 years ago, but that was desperately needed because that aircraft had a phalanx of 1980’s radios, electric gyro’s, incandescent lights everywhere and power-hungry electric gear. My E is pretty thrifty with electricity needs, and the CG is pretty far aft. I might have to put on a three blade prop just to offset the weight loss of an alternator conversion. I don’t think the generator is having any issues, but the regulator is definitely on the fritz. 

[moodychief]

As the OP, I went with a Zeftronics VR but I still have my generator!  I have owned my C model now since 2007 and am on my third generator OH (1500+ hrs, 95% IFR).  I love my generator.  With the Zeftronics it will self flash through the master switch if it isn’t charging.

After initial start I will check to make sure the generator is charging before turning any electronics on.  If it isn’t, I just cycle the master and it comes alive.

 

[vik]

I still have a generator and its regulator from my conversion of E model sitting in the box. PM me if  is interested.

Vik