Alternator

[Cman]

I have an alternator on a John Deere 40. Sometimes it does not charge according to the voltage gauge, it does not excite even at full throttle. I used it for an hour this PM and never did show any charge. Used it Saturday and showed charge the whole time. Is there some way to manually excite the alternator and activate it????????????Thank you.............

 

[old]

I'm guessing it one of those junk one wire jobs right?? Well on some of those you can pull that little cover off and then go buy the plug that fits and wire it up as a 3 wire and doing that will fix the problem. My self I will never use a 1 wire again plus the 3 wire costs you about half what a 1 wire does if not more. I know the last time I checked a 10SI would cost me $35 plus a $10 core and a 1 wire was around $70 plus a $15 core
Hobby farm

 

[Roy Suomi]

I've got a 1 wire alt on my Hobart welder..If it sits in winter storage with the battery disconnected , I have to exite it with a jumper wire..My rebuilder says to just pop that rectangular rubber plug off and touch either terminal from the output terminal..Works everytime..Once it's run for a while it charges fine..

 

[IH2444]

I suspect bad brushes / weak brush springs.

 

[buickanddeere]

40's had a factory ammeter, not a volt meter.
I agree the "simple" one wire alternator is not a simple solution. An oil pressure switch will also work to control the excitation so they don't run the battery down.

 

[Cman]

The alternator is a 10SI Delco and the voltmeter was added when I put the alternator on. This is not origional equipment.

 

[john in la]

Touch a hot wire to the #1 (field) post. This will excite the alternator.

If you find that you still have problems next time we can tell you how to hook the alternator up in a 3 wire setup so it excites the alternator every time you turn the key on.

 

[Bob]

<img src = "http://ndtc3500.stellarnet.com/~blweltin/Bob/AlternatorHarness3.jpg">