Current Electrical Services UK Ltd

Our DC Motor Repair – What to Expect

Initial Assessment

External inspection for physical damage, overheating, contamination (oil, dust, moisture).
Test windings for continuity, insulation resistance, and earth faults.
Check bearings, shaft alignment, and end housings for wear.

Disassembly

Motor is carefully dismantled into rotor (armature), stator/field coils, commutator, brushes, end covers, and bearings.
Each component is tagged, cleaned, and inspected.

Cleaning

Internal parts are degreased and cleaned (solvent, ultrasonic, or high-pressure wash).
Carbon dust around brushes/commutator is removed to prevent tracking faults.

Electrical Repairs

Armature & Field Coils: Tested with a growler or surge tester to identify shorted/grounded coils.
Rewinding: If coils are damaged or burnt, rewinding is carried out with the correct gauge and class of wire/insulation.
Commutator: Skimmed/turned if worn, undercutting mica as needed, and polished to restore smooth contact.

Mechanical Repairs

Bearings: Always replaced with new.
Shafts & Housings: Re-machined if worn or damaged.
Brush Gear: Overhauled, with brush holders cleaned, aligned, and springs adjusted.

Brush Replacement

New brushes (correct grade for the motor and duty) are installed and seated.

Reassembly

Motor is rebuilt, ensuring correct alignment of bearings, rotor, and brush gear.
Fasteners and insulation components are replaced if worn.

Testing & Commissioning

Insulation resistance and winding resistance tested again.
Motor is run on a test bed to check:
- Brush seating and commutation (no excessive sparking).
- Current draw and voltage balance.
- Vibration, noise, and temperature rise.
If applicable, load testing is performed.

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COMPANY REGISTRATION NO. 3976349

DC ELECTRIC MOTOR repairs