SWITCH AS-RELAY 1463504 - Caterpillar

D399, 3512, 3516 Generator Sets With Permanent Magnet-Type ExcitersDescription of Change: The excitation portion of the above generator sets with the permanent magnet-type of excitation has been redesigned. The locations of the main exciter and the permanent magnet exciter have been reversed; the main exciter is now next to the bearing, and the permanent magnet exciter is on the end of the shaft. See illustration. The rotating diodes and suppressor are also changed as shown in the illustration inset.
New locations of the permanent magnet exciter and the main exciter.By changing the location of the main exciter and the permanent magnet exciter, the resonant frequency of the rotating parts is out of the operating rotating range. This gives longer life to the generator shaft.
The 9Y9411 Rectifiers do not have the external flexible leads that were previously used.
Due to the reduced clearance between the permanent magnet exciter stator and permanent magnet rotor, the permanent magnet exciter stator MUST be removed before the generator is separated from the engine to prevent damage to the permanent magnet exciter or to the end of the shaft. When a permanent magnet-type exciter generator is shipped without the engine, the magnet exciter stator will be shipped not installed. This type of stator must be installed and connected after the generator is bolted to the engine.
Adaptable To: It is not practical to install the new parts on earlier generators due to the expense of a new rotor, bracket, and other parts. When the rectifiers are replaced, use a small amount of 5P8937 or 5P9210 Thermal Compound between the rectifiers and their mounting plate.