Generator problems? Battery not charging

[LucasC]

For the electrical savvy guys my 62 M20C battery quit charging on the way home. Backround info, dont know how old the generator is or when brushes were changed. Cant find in log.  I had the old vibrating regulator changed out with a G1500N Zeftronics GCU in march 2018 to get with the times. Today I tried reflashing the generator and took a bunch of readings. Here are the numbers. 

-With GCU disconnected and master on at the GCU and at generator as values were the same 

field-gnd 8.9ohms  

field-arm 7.6ohms

arm-ground 1.5ohms (very high should be 0-0.1ohms, prob why it wasnt kicking on till about 1600-1700rpms before)

-readings at gcu with wires removed were all normal

-after install i have the green GO, green VR and red CL lights on as says i should

bat-case is 12.66v

field to case is 0v

Generator still wont kick on  

What you guys think? Generator?

Thanks for your time

Lucas

 

 

 

 

[MooneyMitch]

I suggest testing generator output.  Reading should be somewhere between 13.6-14.2 volts, above 1200 RPM or so.  

[Yetti]

What do the lights on the zeftronics tell you

[Jerry 5TJ]

Some good old info on the generator / voltage regulator in our C models. 

 

[Jim Peace]

I don't mean to be a smart ass but....

I have almost the same airplane...if you want close to 100% dispatch reliability then you should consider the plane power alternator or whatever the flavor of the month is...

you will save on the labor of trouble shooting and this happening again and again....save some weight .......any new avionics may like it better as well.....

good luck

[N201MKTurbo]

If you can measure it with it running you should see battery voltage across the field terminals and a voltage greater than battery at the output terminal. You might have to make some test wires with ring terminals to get the measurements.

if you see all of this and no rise in system voltage, then the GCU is not connecting the output to the battery. If you don’t see field voltage, then the GCU is not supplying field current. If you have field current but no output, there is a problem with the generator.

A generator cannot be left connected to the battery like an alternator. It has a current path to ground and would rapidly discharge the battery. It has a high current contractor called the circuit breaker that only connects the generator to the battery when it is charging.

The other two functions are the voltage regulator (actually, voltage limiter) and the current limiter which interrupts field current if the charging current is too high.

[moodychief]

I installed a Zeftronics a few years ago.  Every once in a while the generator won’t generate.  We found out if you throttle to 1500-1700 rpms then cycle the master it will come on line.  Never had this problem before the Zeftronics VR was installed.

We spent hours troubleshooting then found this on a fluke.  Only happens infrequently.

Doesnt cost anything to try!

[Guest]

Check the brushes and the condition of the commutator segments, it’s easy to open the brush band cover to look inside.

Grounding the field terminal with a jumper should provide output regulated only by the engine RPM and common sense to not exceed a bus voltage of 14 volts.

Clarence

[jamesm]

zeftronics gcu G1XX0N-PITt-shoot.pdf

Hi Lucas

Years ago I had installed a generator Zeftronics  generator control unit on a '67C.The problem I had was when I purchased a re-manufactured generator that resistance values didn't match Zeftroinics  resistance  requirements. I called the generator  re-manufacture outfit  but they said  it was in Delco Remy specs. So I returned the re-manufactured generator. While original generator was off the airplane I took it to an auto wrecking yard  had them but on their  test fixture (the airplane  generator spins backwards) to ensure the original generator really was putting the proper voltage which was before I re-installed the original generator  as I recall it worked fine.  fast forward in time after I think it was Prop AD or some other  reason why I had  the prop was off. I installed a Plane Power Alternator before Plane Power  had a replacement kit on the market.  After about  12 years  it has  preformed flawlessly. Until recently I am now getting a slight alternator whine.

James '67C

[druidjaidan]

22 hours ago, moodychief said:

I installed a Zeftronics a few years ago.  Every once in a while the generator won’t generate.  We found out if you throttle to 1500-1700 rpms then cycle the master it will come on line.  Never had this problem before the Zeftronics VR was installed.

We spent hours troubleshooting then found this on a fluke.  Only happens infrequently.

Doesnt cost anything to try!

Had this exact behavior after we installed a new zeftronics VR and replaced the failed generator with a one someone gave us after their upgrade to an alternator.  Hasn't happened in about a year now, but we made some other changes that seem to help.  We used to turn on the strobes before starting (no beacon), but we found the problem didn't occur if we left them off.  It's been a while, but I recall something about generators failing to energize the field if there is a load on the system or something.

[FloridaMan]

Check the wires. I had three failures that I thought were the alternator that were wires broken at the connector. I had all of the power wires replaced when I did the engine and have had no issues since. 

Edited August 7, 2019 by FloridaMan

[Jeph357]

https://www.amazon.com/PALUMMA-Charger-Adapter-Display-Battery/dp/B07K16WM3W/ref=asc_df_B07K16WM3W/?tag=bingshoppinga-20&linkCode=df0&hvadid={creative}&hvpos={adposition}&hvnetw=o&hvrand={random}&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl={devicemodel}&hvlocint=&hvlocphy=&hvtargid=pla-4583657822890611&psc=1

This is how I figured out mine wasn't working at all times, Id suggest switching to an alternator, 1. lighter (I gained 4lbs of useful load), 2. charges at lower RPM

Still use this voltmeter (or one like it)  A voltmeter  is  more relevant than an ammeter in my opinion 

[carusoam]

Welcome out into the open, Jeph!

When able... add some details to your avatar area...

Best regards,

-a-