Volt Gauge Readings

[Retiredwarhorses]

My Voltage gauge on the M1109 is about 2 needle widths to the left of the white mark.
On my HMMWV I can adjust the output so this mark lines up nicely....is there an adjustment for the m1009 alternators? or is one just weak?

 

[1956_4x4]

My Voltage gauge on the M1109 is about 2 needle widths to the left of the white mark.
On my HMMWV I can adjust the output so this mark lines up nicely....is there an adjustment for the m1009 alternators? or is one just weak?

There is no adjustment that I know of on these alternators. The alternators both have non-adjustable internal regulators. It might be a good idea to test the output of each alternator.

I just finished repairing the opposite problem about an hour ago. I had an alternator putting out voltage that was a little above specifications. Replaced the internal regulator and all is well again!

Smitty

 

[Retiredwarhorses]

Which one? what should my output voltage be for each unit?

 

[1956_4x4]

Which one? what should my output voltage be for each unit?

I only have the right alternator since I went to a straight 12 volt system. I try to keep these alternators between 13.8 and 14 volts. Mine was pushing 15.1, so I pulled it apart and put a new regulator in it.

If you can load test your electrical system, you can check the output at each alternator. Testers for the 24 volt systems are few and far between. Another way would be to remove the alternators and run them down to the parts store to be tested. They will usually test them for free.

Most of the parts stores have a hard time getting replacement alternators for these trucks (even when we supply the part numbers.) They can be rebuilt easily if you locate the parts. I replaced the following parts in the spare alternator (1105500) I built:

Rectifier - D10
Diode trio - D6
Voltage Regulator - VR-111

Smitty

These are all Standard part numbers.

 

[Retiredwarhorses]

I suspect each Alt should be putting out up to 28vdc?
Or if I remember does only one charge the batteries?

 

[1956_4x4]

I suspect each Alt should be putting out up to 28vdc?
Or if I remember does only one charge the batteries?

Not in a CUCV. They're both 12 volt alternators. They have a floating ground and are wired to supply a 12/24 volt system. Most of the vehicle is actually 12 volt. The starter, power to glow plug resistors, and jumpstart plug are 24 volt.

Smitty