Alternator failed at 90K miles.

[McHughes]

Leece-Nevell 2824LC 160a 14v.   Thinking of replacing it with a Delco 28SI 200a.  My question is about the tach.  

Is the Delco tach signal the same as the Leece-Nevell?

[Frank Bergamo]

Mike,

 

your Leece-Neville is a Duvac alternator. It has a sense wire that runs to chassis batteries. If the alternator you are looking at does not have this provision you are better off getting a brand new Leece-Neville 160 or 200 amp Duvac alternator. Most people rebuild their old alternator and keep it for a spare. Hope this helps.

[John Haggard]

13 minutes ago, McHughes said:

Leece-Nevell 2824LC 160a 14v.   Thinking of replacing it with a Delco 28SI 200a.  My question is about the tach.  

Is the Delco tach signal the same as the Leece-Nevell?

You can get yours rebuilt like new for 3 to 4 hundred 

 

2 minutes ago, Frank Bergamo said:

Mike,

 

your Leece-Neville is a Duvac alternator. It has a sense wire that runs to chassis batteries. If the alternator you are looking at does not have this provision you are better off getting a brand new Leece-Neville 160 or 200 amp Duvac alternator. Most people rebuild their old alternator and keep it for a spare. Hope this helps.

Yes

There was a great thread last week concerning Alternator s

They re built mine while I waited.

1 hour.

$300. Plus tax 

[Chuck B 2004 Windsor]

Frank B is correct.  If you do not replace a alternator that has a DUVAC provision, you will run into a lot of problems.  There are alternator shops out there that have NO understanding about DUVAC.  All they want to do is make a sale.  Chuck B 2004 Windsor

[Ray Davis]

Mike,   I'm pretty sure your tach is not driven by the alternator.   On your 08 electronic engine the tach signal come from the ECM.

However you may have a Duvac alt, I don't know.  It has been recommended on here for the longest to rebuild them because many replacements never work properly.  

[klcdenver]

AJ-Electric is a good source with reasonable prices for the Duvacs. See attached

[McHughes]

Thanks for the feedback.   Rebuilding this unit is questionable. Highly corroded from road salts.  Contemplating doing it myself though.  I had rebuilt dozens in my shop over an 11 year period.

Currently the Leece-Nevell sensor port is simply a wire connection to the chassis batteries. As for the tach there is a wire connected to the tach terminal on the alternator. I believe it taps onto one leg of the diode trio.

The Delco 28SI also has a sensor port and a tach port.  According to the docs the sensor port functions to increase voltage based on cable voltage loss at the battery. Same as the Leece-Nevell was doing.  As for the Delco tach signal the docs say "Frequency = Alternator RPM/10" . Don't know if it is the same as the Leece-Nevell. I suspect it is somewhat standardized.

This coach never had to the old style 3 terminal battery isolator which is what the duvac was to address.

By the way, this coach used to have a Big Boy and Bird which was replaced by a LI-BIM almost two years ago. 

[Ray Davis]

Mike,   Now we learn that you probably know more about these alternators than the rest of us put together.  LOL

You can probably make any alternator work,  but the average guy can't do that.  They are often at the mercy of a mechanic that has no idea what a Duvac alt is.

BTW, if your tach is alt driver it is important that you maintain the same pulley diameter.  I suppose you could tell for sure by disconnecting the tach wire or even  start the engine without the belt and see if the tach still works.

Good luck & let us know how it works out.

Edited June 27, 2021 by Ray Davis

[moxy1962]

I had my 200 amp leave Neville fail due to corrosion at 85000 miles, after much research I decided to replace it with modern Leece Neville 210 amp Duvac alt with ac tach lead, as my coach is Duvac and the new alternator is self exciting but requires signal voltage that it doesn’t receive due to battery isolator I used the Ignition signal lead with inline diode, has function 100 percent for 3 months, only issue is that the alt self excites above my Cummins ISL idle rpm so once starts I literally touch the pedal and alternator engages 

Alternator was still 700 Canadian, but uses modern tech and is considerable smaller unit

Moxy

[McHughes]

I was curious so I did some testing.  Ran the engine without the alternator and sure enough the dash RPM gauge worked just fine.  That signal from the alternator must be used for something else.  Perhaps an indicator or to the ECM.  If I only had a wiring diagram.

[moxy1962]

AC signal also shuts off alt light 

[Ray Davis]

32 minutes ago, McHughes said:

I was curious so I did some testing.  Ran the engine without the alternator and sure enough the dash RPM gauge worked just fine.  That signal from the alternator must be used for something else.  Perhaps an indicator or to the ECM.  If I only had a wiring diagram.

Thank goodness,  I was beginning to question what I thought I knew.  Which ain't much.  LOL

[CTerry]

I have a 2003 Beaver built in 2002. Does anyone know if it has a Duvac alternator. Recently replaced the alternator with a new one. The new had the same numbers and the same terminal hook ups. Have no idea if it was a Duvac or not but everything seems to be working fine. Would change out again but it is a little difficult because of rear radiator.

[moxy1962]

If it’s working and your coach has isolator I would say you are good 

[McHughes]

Ordered the Delco-Remy 28SI to replace the Leece-Neville 2824LC. 

[moxy1962]

You will need a diode and use your ignition wire to activate alternator if you are staying with Duvac style system 

[veraken]

I  replaced my 160 amp Leece Neville 2824LC with a 200 amp Delco Remy 28SI. The install was fairly simple except on the DR you don't connect the excite wire since it is self exciting. I had my old LN rebuilt and carry it as a spare.

[McHughes]

Thanks Bill.  Added a 10a 50v Schottky Diode to the ignition terminal.  Tested. All works well.

[moxy1962]

Glad to help