Leece Neville DUVAC Alternator
My 1996 U320 has a Leece Neville 2824JB alternator (replaced by 2824LC in newer U320s) which has a sticky label with "Modified for use with Duvac System.See Tech Service Letter No 45".
I have seen references in the Foretravel blogs like: "Foretravel motorhomes have unusual alternators". The alternator on my 1996 U320 stopped charging, so I removed it. I noticed four terminals, one labeled "TO #1 TERM OF DUVAC". I also noted the DUVAC label on the alternator. I thought this must be a unique alternator, however it is NOT. An explanation follows.
DUVAC: is a dual voltage system to support the use of 12 volt and 24 volt devices.
The Prestolite web page shows two items related to this:
Firstly: "DUVAC SYSTEM HAS LONGER POSITIVE STUD, REMOTE EXCITE, CASE GROUND" These are modifications which were made at the factory to alternators with the misleading DUVAC label.
Secondly: A technical bulletin detailing field modifications required to connect a "DUVAC LABELED" alternator to a DUVAC system. Modifications include removing the "diode trio" and connecting the smaller terminals to the bushes and to different spots on the regulator.
The Leece Neville alternators installed on Foretravels (and SOBs) with the DUVAC label have been modified to make the field conversion to DUVAC easier, but Foretravel motorhomes do not have a DUVAC system and there is nothing unusual about Foretravel alternators. The DUVAC label is misleading and should be ignored. The terminal labeled with "TO #1 TERM OF DUVAC" should be connected to the battery positive. On my U320 it is connected via the wiring harness to the start battery terminal on the alternator diode isolator block. The alternator negative output terminal has a short (red) battery cable which connects to the engine block.
After uninstalling the alternator, I removed the regulator screws and checked the brushes which were OK. I cleaned all terminals including the very rusty sensing terminal (labeled "TO #1 TERM OF DUVAC"). I had the alternator tested at a local auto electric shop and it tested OK. I will reinstall alternator today and test.
Topic: Leece Neville DUVAC Alternator