Monarch 10ee Drive Motor Retrofit

This page describes my project to replace the motor-generator and DC drive motor in my 1947 Monarch 10ee lathe with a 5hp 3-phase motor and variable-frequency drive.

The MG set developed a bearing problem which caused rapid wear of the generator brushes. One of the brushes eventually bottomed in its holder. By the time I discovered the problem, a two-inch white and blue flame was issuing from the brush and the commutator lands were badly eroded.

I decided to replace the DC motor, MG set and original controls with a 5hp 3-phase motor and a VFD. I think this will suit my requirements, but I suggest that anyone considering a similar endeavor spend some time researching all the available options. A lot of helpful information can be found in the Monarch forum at Practical Machinist.

Now on to the pictures...

Design
Shaft adapter
Adapter plate assembly
Gear and shaft repairs
Installation

Last updated 9/9/03.