Case Study: Motor and Controller Replacement




A Customer had large press motors that had outlived their lives and required frequent repairs. They recently completed a line automation project but realized the motors and magnetics were already past their life expectancy and a direct replacement was not possible. ONYX was engaged to come up with a solution could replace obsolete motor types and could be done in a time limited schedule.


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The Problem

A recently re-tooled press stamping line had main and micro-inch motors that were past life expectancy. The motor type was no longer available and used different technology which did not have a direct replacement in either characteristic or form factor. The line was fully utilized and there was very little time available for modifications. There were additional mechanical wear issues that needed consideration. The customer also wanted a system that was easier to maintain and would allow a faster changeover for replacement and service.

The Solution

ONYX Engineering provided an engineered solution that included motors with similar motor performance and better flexibility and MTTR. A total of eight 350HP motors were replaced with an engineered adapter plate and couplings that not only provided similar performance but allowed the older motors to be temporarily used as backup units if there were to be any issues prior to spare unit deliveries. Pre-fabricated sub-plates were mounted and wired with new soft starters and reversing contactors. They provided a more controlled, less violent start of the motors resulting in less mechanical wear and tear on motor gear boxes. Motor intermediate junction boxes were provided that utilized distribution blocks to make removal and re-installation of motors up to 50% faster than before. Another eight Variable frequency drives replaced older vintage variable frequency drives. Drive performance was matched with previous variable frequency drives decreasing time required for commissioning. The entire changeover and commissioning activities were performed over the Christmas shutdown period of 5 days. Production resumed at the normal scheduled time with little to no impact on production.

The Results

The Motor and drive replacements increased the usability and efficiency of the existing equipment. It provides trouble-free operation of the presses and an updated stock of components which should provide worry free operation of their large motors on the line for the foreseeable future. All of this was achieved on schedule and within budget with little or no impact on production.

Project Details








Major Automotive Manufacturer


1 - Project Manager
3 - Controls Engineers
4 - Manufacturing
18 - Skilled Trades



Services Provided

Control engineering and design

Panel fabrication to UL508A

PLC programming 

Drive Programming 

Installation Services

Start-up and commissioning



Allen-Bradley SMC Soft Starters

Siemens 1LE5 Series motors

SEW Movitrac VFD’s