alternator not charging

[modelaonly.com]

Have been building alternators for years,could not get one to charge at idle, finely figured it out. my engine builder installed a small crank pulley.slowed down the revolutions to much,[sometimes things just dont work so well!]

 

[Cajun]

If you rev the engine a bit it will probably start charging and continue to charge at idle.

 

[Jim Brierley]

On the first alternator I installed it wouldn't charge until very high RPM'a were reached, once it started, it stayed charging until shut off again. I installed a diode in the line that feeds the field (F) terminal and it would charge at idle. A small pulley must be used on the alternator to get enough RPM for it to charge. Modern cars have large crank pulleys that speed things up.

 

[modelaonly.com]

went back to a stock CRANK pully all is well now. thanks all!