Brush pack for a water cooled alternator

[panason1c]

My ML has covered well over 100k miles so i thought it wise to replace the alternator brush pack as a preventative measure.....I enquired at MB and they said that brush packs were not available as spares for the water cooled alternators and the only option was to buy a new one! (exchange unit)

Has anyone here sourced/fitted a brush pack to a water cooled alternator?......if so, part number?

 

[BlackC55]

I am sure someone here can help and has done this before. I can't remember who though.

 

[television]

The alternators do have spare parts listed and the part numbers.

http://www.detali.ru/cat/oem_mb2.as...GA=722.662&CT=F&cat=06H&SID=54&SGR=026&SGN=03


Have you tried Bosch, if it is a Bosch

 

[panason1c]

The alternators do have spare parts listed and the part numbers.

http://www.detali.ru/cat/oem_mb2.as...GA=722.662&CT=F&cat=06H&SID=54&SGR=026&SGN=03


Have you tried Bosch, if it is a Bosch

The MB partsman said that it is only the water cooled alternators that they dont show parts for, i guess therefore that the link above is for a non-water cooled alternator (wca).

He determined from the chassis number that i have a wca fitted but couldnt find info on who the manufacturer was.

 

[television]

Not easy working out the link as to what is what but 2 brush packs are shown.

I know nothing about WCA how do they work, and where does the water part cool it

 

[panason1c]

Not easy working out the link as to what is what but 2 brush packs are shown.

I know nothing about WCA how do they work, and where does the water part cool it

According to the partsman, the water cooled alternator is 190amp and is a higher output than the non-wca version which is why it needs to be cooled due to it getting hotter in operation..............Though i've not had a thorough look i cant see any hoses leading to/from the alternator so i'm assuming either the water jacket (if it exists on mine) is fed directly from the engine block...or the partsman was wrong when he said i had a wca........

 

[television]

Do you have WIS, as you know I do and am happy to look it up if it is accurate on this issue.

By checking the replacing alternator section that should give a clue as to what is fitted

 

[panason1c]

Do you have WIS, as you know I do and am happy to look it up if it is accurate on this issue.

By checking the replacing alternator section that should give a clue as to what is fitted

Cheers, would appreciate that...........Do you need the last 6 vin numbers?........they are 756142

 

[television]

Cheers, would appreciate that...........Do you need the last 6 vin numbers?........they are 756142

No its the 3 after 163???

 

[panason1c]

No its the 3 after 163???

Ok.......113

 

[MIW615]

Not easy working out the link as to what is what but 2 brush packs are shown.

I know nothing about WCA how do they work, and where does the water part cool it

I have to say most of this is news to me - found it on the internet

Alternators, work like this:The field coils are not stationary in an alternator. They are wound around a large bobbin and surrounded by two interlocking 'clawfoot' iron shells (extend your fingers and mesh them together to see what I'm talking about). The coil is attached to two copper slip rings which the regulator applies power to through two copper and carbon brushes to control the charging of the alternator. The whole rotating assembly is known as a 'rotor'. When the rotor is energized, the effect produced is that the top shell becomes a magnetic 'north' and the bottom shell becomes a magnetic 'south'. In the alternator, there is a stationary set of windings wrapped around a steel core known as the 'stator'. The rotor spins inside of the stator. As the rotor spins, the alternating between north and south poles (remember the 'clawfoot' design of the rotor!) induces a current in the stator. However, the current induced is alternating current - hence the name 'alternator'. The output current from the stator then passes through a set of six to eight parralel-wired diodes - three or four positive diodes and three of four negative diodes, which polarize (or 'rectify', hence why the assembly which hold the diodes is called a 'rectifier') the AC output into distinct positives and negatives. The negative bridge of the rectifier connects directly to the alternator housing, which is of course grounded to the engine block, while the positive bridge connects to the output stud, which then goes back to the battery.

There are several advantages and disadvantages to alternators. Because of the nature of their design, alternators can produce much higher output than generators - current designs on luxury cars produce upwards of 140 amps. Since the brushes on an alternator only need to carry the current necessary to power the rotor (about 7A maximum) and the slip rings that they ride on are continuous and smooth, they last exponentially longer than generator brushes do - about 120-150,000 miles. There are some disadvantages to alternators, though. The Lundell alternator (the technical name for a clawfoot-rotor alternator) requires two watts of energy(power? my terminology is slipping) to spin it for every one watt that it produces. It is not an incredibly efficient way to produce electricity. Alternators also rely on diodes to rectify their AC output. These diodes only last so many thermal cycles and some of the newer zener ('avalanche') diodes are designed to be self-sacrificial by shunting large output spikes to ground to help save the sophisticated on-board electronics found on today's vehicles. Today's alternators also produce high output from a very small package, which means that there is not a large enough case to act as a heat sink. The high heat helps shorten the life of the diode chips significantly.

There are several new alternator designs out there - General Motors has gone to water-cooled alternators (yes, there are 5/8" hose nipples on the back of the alternator) to keep the diodes cool on the newer model 4.6L Northstar V8s. BMW has designed a combination starter/alternator which is built into the engine's flywheel. The expected switch from 12V to 36V or 42V systems, as well as single-wire multiplexed vehicle systems in the next couple of years also promises to push alternator technology ahead further.

 

[television]

Yes it is the water cooled type you should see a black pipe coming out of the block just above the rear of the alternator, going down into it, it looks to be about 8" long.

As always on here the only cure if faulty reg pack, exchange alternator, but they say this on everyone.

The number given is BE15. 40-P 1001-02A

lets hope it is a Bosch as spare parts are available.

Best I can do, No point in sending a print out at this stage for removal

 

[panason1c]

Yes it is the water cooled type you should see a black pipe coming out of the block just above the rear of the alternator, going down into it, it looks to be about 8" long.

As always on here the only cure if faulty reg pack, exchange alternator, but they say this on everyone.

The number given is BE15. 40-P 1001-02A

lets hope it is a Bosch as spare parts are available.

Best I can do, No point in sending a print out at this stage for removal

Many thanks for that...........just had a look, not easy to see much but i did see the pipe you described so that at least confirms i have a wca....... i think i'll just leave it alone for now and hope it continues to be trouble free for a while longer as trying to source a brush pack appears to be more involved than i first thought it would be.

 

[television]

I have to say most of this is news to me - found it on the internet


There are several new alternator designs out there - General Motors has gone to water-cooled alternators (yes, there are 5/8" hose nipples on the back of the alternator) to keep the diodes cool on the newer model 4.6L Northstar V8s. BMW has designed a combination starter/alternator which is built into the engine's flywheel. The expected switch from 12V to 36V or 42V systems, as well as single-wire multiplexed vehicle systems in the next couple of years also promises to push alternator technology ahead further.

Heat and semiconductors is a delicate balance before thermal runaway takes place, in the service trade just putting a finger on the heat sinks tell you a lot about how the thing is running, it a shame the the reg pack cant be fitted elsewhere, but in general they do not do too bad, the A class also has a water cooled alternator, probably a Valeo