I was researching some information on my Mercedes Sprinter alternator and came across this little video. Short and to the point. If you are 'old school' you may not have noticed this 'advance' in alternator construction. I would think all new vehicles, particularly diesel will have one. What appears to be a simple solid pulley that is expected to last a lifetime is no longer so benign. Water crossings, dust and hard use charging extra batteries would not be expected to improve the life of them. They can make odd noises too when failing, which are hard to locate.
Youll find these on the modern variable voltage alternators.
Once the battery has fully charged (according to the vehicles ecm) it switches off the alternator and this type of pulley system allows the free wheeling of the pulley without any voltage output, less load on engine= better fuel economy!!
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Youll find these on the modern variable voltage alternators. Once the battery has fully charged (according to the vehicles ecm) it switches off the alternator and this type of pulley system allows the free wheeling of the pulley without any voltage output, less load on engine= better fuel economy!!
Hi kezngaz
You are right in saying you will find these on the modern alternators. In fact all modern alternators AFAIK.
However your explanation of how it switches off the alternator and it freewheels is incorrect, I am sorry to say. The alternator continues to turn all the time but it does switch it down to reduce the voltage output to save load etc.
The reason for the overrunning clutch is more complicated and involves the belt drive and cyclic fluctuations in speed. I suggest people Google it if interested as they are a fixture on engines now.
My point in showing it is to alert some old hands, who may not think to look at the pulley when a problem arises. They never failed in the old days but they do now.
What appears to be a simple solid pulley that is expected to last a lifetime is no longer so benign. Water crossings, dust and hard use charging extra batteries would not be expected to improve the life of them. They can make odd noises too when failing, which are hard to locate.
but it does switch it down to reduce the voltage output to save load etc.
but they do now.
