Electric motor repair specialist Marthinusen & Coutts (M&C) successfully completed the urgent repair of a 94 t, 4 736 kW direct current, mine winder motor under a tight deadline at platinum-group metals producer Northam Platinum’s Zondereinde mine, near Thabazimbi, in Limpopo.

The motor, which failed in July last year, had driven the personnel winder hoist serving the mine’s Number 1 shaft, and is therefore critical to the mine’s operation.

M&C was given five days to perform all the necessary repairs after taking delivery of the motor at its workshop in Cleveland, Johannesburg.

“The clock started ticking when we took delivery of it, with the repairs having to be completed and the motor fully reassembled [five days later] when it was due to be collected and returned to site for re-installation,” says M&C projects and field service manager Owen Kilian.

The repair process focused on one of the motor’s field coils, which had to be rewound after damage was detected; while M&C’s team also replaced deteriorated insulation and conducted a thorough chemical wash of all components in their power generation workshop, in Benoni.

To reduce disruption at the underground mine while the failed motor was being repaired, M&C provided a field service team to assist the mine’s personnel with transferring an identical motor from the rock winder hoist at Number 1 shaft to replace the failed motor, to ensure the personnel winder hoist continued working.

“The plan was to install the repaired motor to drive the rock-winder upon its return, which our field service team was also assigned to assist in installing, as part of our contract,” notes Kilian.

Northam granted an additional five days under the repair contract for the onsite work carried out by the M&C team, with some repair procedures also completed onsite including refurbishing the armature of the repaired winder motor.

“Without the excellent teamwork we were fortunate enough to share with the expert mine personnel and their rigging subcontractors, we wouldn’t have completed the job in the very limited time we were given,” he states.

Electrical equipment manufacturer and supplier ACTOM Industry, representing the original-equipment manufacturer (OEM) for the winder motors, proved invaluable in ensuring that the repairs conducted were in accordance with the OEM’s quality standards, concludes Kilian.