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Brushless Exciters

Brushless Exciters Rectifiers mount directly on the exciters shaft and rotate at the machine speed.  Brackets and insulators which are used in these assemblies can wear with time due to vibration and repair operations.

AC Motor Technologies has the materials and techniques available to replace existing parts and/or up-grade an existing assembly.

There are several manufacturers of Brushless Synchronous Machines.  Test instructions are usually not provided with the Machine or with the purchase of replacement parts for these rectifiers.

AC Motor Technologies, Inc. has prepared instructions for repair of the exciter and rectifier, including methods for electrical connections and hardware mounting to insure long-term performance.

Brushless Exciter-Rectifier System

On-Site Training

When requested, a training course can been provided, on site, for the repair, testing and machine testing for center technicians.  A manual is provided which includes the necessary test instructions, schematic, test equipment description, and guidelines for repair.

A usual limitation at service centers is the machine testing power supply.  These supplies are set up for Induction motors and require a little manipulation to successfully start and synchronize a synchronous machine.  A separate exciter field supply is also required.   The techniques and field supply details are described and demonstrated.


Brushless Exciters have been in service for many years.  On older units, changes can be made to the circuit components of the rectifier which will improve synchronizing performance.

Semiconductor Replacements

Replacement of the older power semiconductors can be difficult due to changes in semiconductor designs and obsolescing of some models.

AC Motor Technologies, Inc. can assist in the selection of components which will provide for continuing long-term operation.