Newfangled alternator clutch pulley check and replace!
Jaahn said
12:03 PM Nov 16, 2016
Hi
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.
https://www.youtube.com/watch?v=fyosuYbPxr4
enjoy the accent
Jaahn
Tony Bev said
03:51 PM Nov 16, 2016
Thanks for this info Jaahn, it was something that I was unaware of
ants_oz said
03:58 PM Nov 16, 2016
Yes, overrunning alternator pulleys.....
Had one fail on a previous vehicle (D40 Navara). Made one heck of a mess.
They can be replaced with a solid pulley, however these can cause issues with the alternator due to introducing different harmonics.
kezngaz said
12:15 PM Nov 22, 2016
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!!
Jaahn said
08:19 PM Nov 22, 2016
kezngaz wrote:
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.
Jaahn
kezngaz said
07:12 PM Nov 24, 2016
Thanks jaahn, the more info out there the better. Thats what's so good with this forum.
Kezngaz.
Hi
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.
https://www.youtube.com/watch?v=fyosuYbPxr4
enjoy the accent
Jaahn
Thanks for this info Jaahn, it was something that I was unaware of
Had one fail on a previous vehicle (D40 Navara). Made one heck of a mess.
They can be replaced with a solid pulley, however these can cause issues with the alternator due to introducing different harmonics.
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.
Jaahn
Kezngaz.