Alternator maintenance

**madduck** · August 31st, 2013 07:59 PM

I was driving our van earlier today when I smell something burning. I flipped up the front seat and observed the engine and saw the alternator not turning. The fan belt sliding and burning. I brought the alternator to the shop and the bearing needs replacement so as the carbon stick inside.

If this happens on a car, I probably wouldn't have noticed it until it breaks down. So I wonder what are the maintenance for the alternator? The carbon is inside so do i need to check that for a period of time and what will happen if it runs out of that carbon stick?

**jick.cejoco** · August 31st, 2013 08:39 PM

Originally Posted by madduck

I was driving our van earlier today when I smell something burning. I flipped up the front seat and observed the engine and saw the alternator not turning. The fan belt sliding and burning. I brought the alternator to the shop and the bearing needs replacement so as the carbon stick inside.

If this happens on a car, I probably wouldn't have noticed it until it breaks down. So I wonder what are the maintenance for the alternator? The carbon is inside so do i need to check that for a period of time and what will happen if it runs out of that carbon stick?

alternators have about the same service life that of the starter on the average. it is five years or 100,000 miles. they don't usually need attention until you get paranoid about it. to make sure, have it checked every five years or serviced at around the 100k mile mark

**rmsoriano** · August 31st, 2013 08:56 PM

Originally Posted by madduck

I was driving our van earlier today when I smell something burning. I flipped up the front seat and observed the engine and saw the alternator not turning. The fan belt sliding and burning. I brought the alternator to the shop and the bearing needs replacement so as the carbon stick inside.

If this happens on a car, I probably wouldn't have noticed it until it breaks down. So I wonder what are the maintenance for the alternator? The carbon is inside so do i need to check that for a period of time and what will happen if it runs out of that carbon stick?

I am not 100% sure, but I have seen so many dismantled alternator units in the past and they are constructed similar to a 3 phase generator, meaning, it doesn't have a carbon brush that needs to be replaced... maybe it's just a stuck up or faulty bearing.
Usually, its the bearing, IC voltage regulator and the rectifier which sometime fail.
In your van's case, maybe its just really a faulty bearing....

**rmsoriano** · August 31st, 2013 09:07 PM

Our car's starter motor is a DC motor, it has a carbon brush or carbon stick that the TS have mentioned....

**jick.cejoco** · August 31st, 2013 09:11 PM

Originally Posted by rmsoriano

I am not 100% sure, but I have seen so many dismantled alternator units in the past and they are constructed similar to a 3 phase generator, meaning, it doesn't have a carbon brush that needs to be replaced... maybe it's just a stuck up or faulty bearing.
Usually, its the bearing, IC voltage regulator and the rectifier which sometime fail.
In your van's case, maybe its just really a faulty bearing....

it doesn't have a carbon brush that needs to be replaced

the pair of carbon brushes are the only means of connecting the rotating field coil to the power source, the voltage regulator and the ground. over time, they wear out as a result of constant friction between the slip rings and the brushes. if the rotor is stuck, usually it is the bearing or in some cases rust building up between the claw poles of the rotor and the stator laminated core.

**rmsoriano** · August 31st, 2013 09:18 PM

yes sir, that's why i am not 100% sure, but there are design that also uses carbon brushes, these are those tha does not have permanent magnet in the rotating field.

Originally Posted by jick.cejoco

it doesn't have a carbon brush that needs to be replaced

the pair of carbon brushes are the only means of connecting the rotating field coil to the power source, the voltage regulator and the ground. over time, they wear out as a result of constant friction between the slip rings and the brushes. if the rotor is stuck, usually it is the bearing or in some cases rust building up between the claw poles of the rotor and the stator laminated core.

**jick.cejoco** · August 31st, 2013 09:23 PM

Originally Posted by rmsoriano

yes sir, that's why i am not 100% sure, but there are design that also uses carbon brushes, these are those tha does not have permanent magnet in the rotating field.

if you have a permanent magnet rotating field coil, how do you regulate voltage from a constantly changing rotational speed of the car's engine?

**rmsoriano** · August 31st, 2013 09:42 PM

Originally Posted by jick.cejoco

if you have a permanent magnet rotating field coil, how do you regulate voltage from a constantly changing rotational speed of the car's engine?

I am sorry sir, but earlier I was thinking of a brush-less alternator.. I know that it is possible to have a regulated voltage output in a brushless alternator. and yes, maybe it is not from a permanent magnet....

**jick.cejoco** · August 31st, 2013 09:48 PM

Originally Posted by rmsoriano

I am sorry sir, but earlier I was thinking of a brush-less alternator.. I know that it is possible to have a regulated voltage output in a brushless alternator. and yes, maybe it is not from a permanent magnet....

no need to apologize. no harm done. but so far, all the alternators i worked on from bosch, nippon denso, motorcraft, mitsubishi, delco remy, delco, hitachi and other automotive alternators all have carbon brushes except the motor/regenerative alternator of the toyota prius

**Chinoi** · September 1st, 2013 05:57 PM

There's no way that a carbon brush will stop rotation of armature of alternator. Carbon brush was enclosed in a metal casing and can not able to dislodge to cause obstruction.