Are there Bosch alternator rebuild kit/which ones do you recommend? - PeachParts Mercedes-Benz Forum

turbobenz · #1 02-27-2013, 12:18 AM

How exactly does the reg know its target voltage and how does it physically adjust the field current? Is there a transistor under that black cap?

jay_bob · #2 02-27-2013, 06:49 AM

Quote:

Originally Posted by turbobenz

How exactly does the reg know its target voltage and how does it physically adjust the field current? Is there a transistor under that black cap?

Yes there are electronics under that black cap. That is how it knows the target voltage.

As to the naming convention that is how I remember from school. When I get home I will have to pull out my rotating machines class book (I still have it) and review...

I will be seeing the service guys from a gen manufacturer today at the site I am on, I will ask them what they call the windings if I get a chance. (I don't work for the gen manufacturer, I am on the power switchgear side of the system.)

Edit 28-Feb-2013: the terms the manufacturer guys use are "rotor" and "stator". I went back and pulled out my book from my rotating machines class, and it uses "armature" and "field" even for ac machines. Further research leads me to believe "rotor" and "stator" are indeed the correct terms. I updated original post above.

Mölyapina · #3 02-27-2013, 09:53 AM

Quote:

Originally Posted by jay_bob

Note: Stretch did a write up on rebuilding an alternator a while back.

Yeah, that's what inspired me... I want to take one apart myself

. Thank you very much for taking the time to write that alternator write-up! I enjoyed it.

Quote:

Originally Posted by jay_bob

I play with huge ones at work, the big boys work just like the one in your car except:
- we have a honking 60 L, 16-cylinder, quad turbo Diesel engine for a prime mover, the typical electrical output is 2.5 MegaWatts, your house uses less than 5 kiloWatts on average. The typical data center has no less than two, and sometimes up to 16 or more, of these generators.
- the engine typically burns 150 gal/hr at full load
- we don't use diodes, we want to stay with a 3 phase ac output (usually 480 V but sometimes 4160 or 13800 V)
- and I can assure you that if the regulator does not excite the field, we get no electricity...

Whoa. And I thought that the 7.3L Ford diesel was big...

Quote:

Originally Posted by jay_bob

Final thought, if your brushes are wearing down, replace the regulator before the brush holders dig into the slip rings. If those get damaged severely, the alternator can become scrap metal...

Righto.

Quote:

Originally Posted by Diesel911

You did not say if your Alternator was not charging or if it was just an issue with the Bearings.

I'm getting Squiggledog's core, so I have no idea. I'll see if he does.

Quote:

Originally Posted by Diesel911

If it was not Charging and it was not the Voltage Regulator of Brushes it could be an issue with the Diodes or some of the other parts. They would need a more step by step trouble shooting process.

All right. I have a multimeter (three, actually), so I can use Strech's diagnosis guide...

Quote:

Originally Posted by Diesel911

commutator? Another term for it is the slip ring. Some where in the repair Links someone posted on getting a new Slip Ring and over 4 years ago it was about $6.

Okay. I may try to find that thread...

Quote:

Originally Posted by Diesel911

When I replaced the Bearings on mine I got them from eBay. The Bearing Numbers are often imprinted on the Bearing Shields on small bearings and some times in tiny Letters and Number on the Bearing itself.

I may be buying a set of SKF alternator bearings from qwerty, but otherwise I'll look to eBay or the helpful links you provided. Thank you!

Squiggle Dog · #4 02-27-2013, 10:38 AM

The bearings of the alternator seemed to be fine, but the alternator was no longer charging the battery. I replaced the voltage regulator with a new Bosch one, but it still wouldn't put out a charge. It had a lot of grease and dirt at the mounting points, so maybe it was just not grounded well enough anymore. But, I decided I wanted to upgrade to an 80 amp alternator, so it was worth replacing anyway. The slip rings seem to have a good amount of wear.