Electricity and Control May 2022

DRIVES, MOTORS + SWITCHGEAR : PRODUCTS + SERVICES

Refurbishment of winder motor for Northam Platinum

The South African market is increasingly recognising Marthinusen & Coutts’ capabilities in the area of resto ration and modernisation of old electrical equipment to ‘as new’ status. This capability is also associated with significant cost savings. Northam Platinum recently acquired a used 4 300 kW winder dc motor to drive the hoist due to be installed in the new Number 3 Shaft for the Zondereinde Western Extension of the mine near Thabazimbi in Limpopo. At the beginning of 2021 DRA, the consulting engi neers for Zondereinde, contracted M&C to inspect and test the 37-year-old motor and drive shaft and perform any repairs that needed to be done. M&C was also com missioned, as part of the contract, to manufacture a num ber of key spare parts for the motor. The work was performed at M&C’s Large Motor repair facility in Benoni, which is equipped to handle very large rotating machinery, and was completed in mid November 2021. The motor’s 42 t armature was found to be in good working order, and the frame’s interpole coils and brush gear were partially refurbished and cleaned. M&C applied reverse engineering methods to man ufacture the spare parts for the motor, which comprised

three of each of field coils, interpoles and pole shoes, plus a full set of 24 damper bars – eight for each of the three spare pole shoes. “The units were extremely com plex to assess and it was a challenge to manufacture all the new spares and replacement parts required,” said Rudi Els, General Manager of M&C’s Power Generation & Large Motor repair facility. “There were thousands of differ ent parts, which required a great deal of attention to detail and spe cialist reverse engineering. It was also a major task to document and control the status of all these parts,” he added. The 38 t, 10.5 m long drive shaft was found to be in good order.

Winder Assistant, Donald Kolobe, aligns the brushgear of the 4 300 kW mine winder motor.

For more information contact Marthinusen & Coutts. Tel: +27 (0)11 422 5192 Visit: www.mandc.co.za

MAY 2022 Electricity + Control

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