Urgent Repair of 22000BHP DC Motor after flash

In December 2014, Maintenance Partners was contacted by a French steel manufacturer after a critical DC motor had failed. The failed DC motor drives the factory’s main cold milling line and the failure caused production to cease. Our customer, ASCOmetal in Dunkirk, is specialized in large diameter special steel products up to 310 mm such as crankshafts, camshafts and tubes. The cold mill produces high quality steel for the automotive industry.

Unexpected Failure

The 22000BHP DC motor had been running well for 6 months after an overhaul, but failed unexpectedly in December. The first inspection showed that overheating caused a connection in the armature circuit to burn. This caused a flash which damaged 14 coils in the upper coil side of the rotor, along with a field coil and an auxiliary coil.

Field & Workshop repairs

Because the cold mill’s production had ceased almost entirely, a quick solution was required. A planning was drawn up in coordination with the customer to ensure that the DC motor would be up and running again as soon as possible. On January 5, a team of 4 specialists started working onsite for 2.5 weeks in two 10-hour shifts to repair the 14 damaged rotor coils. After this, the rotor was placed on motorized rollers to apply new bandages.

In meantime, new compensation bars, special nuts and bolts and connection bars were built in the workshop in Zwijndrecht. Besides this, the brush gear was also thoroughly revised and fitted with new insulation material. Assembling and installing the DC motor eventually took 8 days.

Production Resumed

The repaired DC motor was successfully started up on January 31. Production was resumed and the DC motor has been running full time without trouble since. This urgent repair shows how Maintenance Partners’ flexibility and expertise can make the difference. A tight planning of workshop and field activities reduced production losses to a minimum and a machine that is critical to the production process now runs continuously.

More information

Do you want to know more about our services on electrical rotating equipment? Contact us by phone at +32 (0) 3 744 1501 or send us a message through the contact page.

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