One of our standard repair processes is the overhaul of industrial DC motors. These are the main workhorse for steel and metal producing companies where they often drive a drawbench which pulls the steel or metal that is being processed. These types of shunt wound DC motors are very useful for this application as they provide constant torque and variable speed. This ABB DC motor overhaul was needed as over time carbon dust from the brushes builds up inside the motor along with other debris that can cause the winding insulation to fail in a worse case scenario. The bearings also have to be replaced at the correct interval taking into account the L10 bearing life.

This example of a 287kw ABB DC motor is one that we recently overhauled and rebuilt for one of our metal processing customers. Following dismantling & a full cleaning cycle of all the components, this motor underwent a Baker and surge test to the armature, field and interpole windings. This enables us to check the integrity of the winding insulation both to earth and between each individual conductor. The resistance of all the coils within the individual winding circuits was then measured and the motor passed all of these static tests.

Following this, the motor components were stoved and all windings re-impregnated with anti-tracking varnish. The armature then went through to our balancing department where is was dynamically balanced to ensure efficient and smooth running and to maximise the bearing life. The bearing journals and housings were then checked for wear and replacement bearings fitted. The commutator was machined, undercut and polished to ensure the brushes had a smooth and even brushtrack which reduces wear & heat generation and keeps the machine running efficiently. The brushgear was then fully overhauled with new carbon brushes fitted.

Finally the force ventilation blower was serviced and rebuilt with a new motor being fitted & after assembly the coupling re-greased and refitted. The motor then underwent an extensive run test with the brushes being correctly bedded in before being painted and returned to the customer.

This ABB DC motor overhaul is all part of our outstanding motor repair service which we carry out on a daily basis. To accompany this, should you need to purchase a replacement motor, we supply new DC motors to order and also carry a large range of reconditioned DC motors.