Switching from DC to AC

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Scenario

A local company, in the extrusion industry, was looking to continue its process of converting production lines from DC to AC electric motors and inverter drives. This was the third line to undergo the conversion. Its ageing Dc motors and controllers were becoming less reliable, more costly to maintain and spare parts availability was concerning. BAWCo was approached to evaluate and assist.

Solution

The ideal solution was to replace all existing DC motors on the line with Brook Crompton IE3, High Efficiency W Series AC motors. These would then be modified to meet the specific requirements of their application, which in the case of the belt-driven, 90kW motor included:

Fitting drive-end roller bearings – to assist with the radial load applied to the shaft.

Fitting insulated bearings – to suit inverter application.

Fitting a 1024 PPR 24V Encoder – for improved speed control, feedback and positioning.

Forced Vent cooling – to ensure motor cooling at lower speeds.

After the necessary modifications were applied to each motor, they were then delivered to site for installation and commissioning.

Evaluation

Site visits were made to assess the application, locations of existing motors, mechanical and physical restrictions. The extruder consists of many motors and associated drives. This project would include a range from 1.5kW to 90kW the larger of which were belt-drives. The smaller motors were used on direct drive gearbox applications