DC Motor Repair

Overhauls and Repairs

BAWCo has been repairing DC motors from our Bradford workshop for over 100 years. As AEMT members and an ISO 9001-accredited company, we work to recognised industry standards on every job.

No two DC motors are the same, so we assess each one individually and build a repair plan around it. Take a look at our overhauls and most common repairs below.

100+ Years Experience
in DC Motor Repairs
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Regular DC motor servicing identifies developing faults, covers common repairs like bearing replacement, and cleans fans and fins to improve efficiency.

Recommendations

We recommend this based on the motor quality, application, operating time and capacity.

Recommended service times based on operating capacity:
100% 1-2 Years
75% 2-3 Years
50% 3-5 Years

Overhaul Procedure

  • Dismantle the motor
  • Test stator windings – Check resistance, insulation to earth, insulation between windings, and magnetism
  • Test armature windings – Insulation to earth, voltage drop test, and check for dead shorts
  • Inspect and replace carbon brushes if required
  • Clean brush gear and check for carbon buildup or damage
  • Jet wash, oven-stove, and varnish windings
  • Replace bearings and seals
  • Assemble the motor, perform final tests, and run
DC Electric Motor Repair
DC Motor Service Carbon Brushes
DC Motor Overhaul

Possible Problems

  • Overspinning
  • Overcurrent
  • Underperforming
  • Increased heat

DC Motor Rewind (Field Coil)

  1. Detail and strip the windings
  2. Remove old insulation and clean the core pack
  3. Insulate slots with the required heat class (Class F or Class H)
  4. Wind, connect, and test
  5. Impregnate with varnish and oven-stove
  6. Assemble the motor, perform final tests, and run
DC Motor Rewind in the BAWCo Workshop
DC Field Coil Rewind
Completed DC Field Coil Rewind by BAWCo

Possible Problems

  • Overcurrent
  • Underperforming
  • Cogging
  • Sparking
  • Blown

DC Motor Rewind (Armature)

  1. Detail and strip the windings
  2. Test the commutator
  3. Remove old insulation and clean the core pack
  4. Insulate slots with the required heat class (Class F or Class H)
  5. Wind and connect wires to the commutator and solder
  6. Test, impregnate with varnish, and oven-stove
  7. Skim and undercut the commutator
  8. Balance the armature to required ISO G Grades
  9. Perform insulation and voltage drop tests on the armature
  10. Assemble the motor, perform final tests, and run
DC Armature Rewind
DC Armature completed rewind by BAWCo Bradford
DC Armature Repair by BAWCo

Possible Problems

  • Excessive noise
  • Excessive heat on the endshield or shafts
  • Rotor mechanically locked up
  • Application wear or damage due to misalignment

Bearing Housing and Surface Repair

  1. Strip the motor down
  2. Remove the old bearings
  3. Measure the shaft and housings for wear – perform engineering work on worn surfaces to bring them back within tolerance
  4. Fit new bearings
  5. Assemble the motor, perform final tests, and run
Bearing Housing and Surface Before
Bearing Housing and Surface Repair
Bearing Housing and Surface Close up

Possible Problems

  • Visual inconstancies
    • Signs of melting insulation on the leads
    • Cracking or discolouration of the leads
    • Blown lead
  • Unbalanced resistances or open circuit
  • Unbalanced resistances or open circuit

Re-lead Windings

  1. Dismantle the motor
  2. Cut the leads back to the connections
  3. Test windings in case further action is needed
  4. Connect new leads and terminate
  5. Varnish and oven-stove windings
  6. Assemble the DC motor, perform final tests, and run
DC Motor Re-lead Before Picture
DC Motor Re-lead Repair Picture
DC Motor Re-lead After Picture

Possible Problems

  • Visual inspection
  • Measures below tolerance

Diagnostic

  1. Clock the shaft for trueness
  2. Measure to check the exact size

Example Repair Procedure

  1. Dismantle the motor
  2. Remove bearings
  3. Perform engineering work to build the shaft back up and turn it concentric
  4. Fit new bearings
  5. Assemble the motor, perform final tests, and run
Worn Shaft
Worn Drive Shaft Top View
Worn Shaft Close up

Stocked DC Motor Parts

  • Endshields
  • Terminal blocks and boxes
  • Feet/ Flange mounting points
  • Cable glands
  • Inspection covers
  • Tacho
  • Unbalanced resistances or open circuit

Replace and Repair

BAWCo has fast access to carbon brushes, brush holders, brush springs, copper strips and commutators for DC motor repairs. We also hold compatible spares for other components and can offer repair services if required.

Broken Fan Part
Electric Motor Spares in BAWCo Workshop
Broken Parts Replacement from BAWCo

Possible Problems

  • Excessive noise and vibrations
  • Poor airflow
  • Excessive heat
  • Overcurrent
  • Unbalanced resistances or open circuit

Force Vent Unit Repair

  1. Dismantle the motor
  2. Clean the fan and motor
  3. Test the windings
  4. Inspect mechanical surfaces
  5. Replace bearings
  6. Assemble the unit, perform final tests, and run
Forced Vent Unit Side View
Forced Vent Unit Front View
Forced Vent Unit Picture 3

24/7

Emergency Response

22

Full-time engineers

5 Tonne

Lifting Capacity

ISO 9001

Quality Certified

Why BAWCo?

DC motor repair is only part of the job. Here’s what you get when you choose BAWCo.

Decades of Knowledge

DC motors are less common than they used to be, but our engineers know them inside out. That expertise has been passed down through generations at BAWCo.

Trusted by Industry Leaders

BAWCo supplies and repairs motors for industry leaders across the UK, including Yorkshire Water, Ineos, Tioxide, Kone and Solenis.

Collection and Delivery

Your motor is collected, repaired, and delivered back to you, using our own vehicles locally or trusted couriers nationally.

BAWCo is ISO 9001:2015 certified for quality management BAWCo is an AEMT member BAWCo is an authorised Brook Crompton repairer BAWCo is Achilles approved BAWCo is SafeContractor approved BAWCo is an ATEX-approved repairer of hazardous area motors

Frequently Asked Questions

Still have questions? Here’s what customers ask us most.

DC motor repair timescales vary depending on the type of rewind. A DC armature rewind typically takes 7 to 35 days, while a field coil rewind takes 7 to 21 days. Special-design armatures can extend these lead times considerably, since size and design both affect the work involved.

Yes. We repair DC motors from all manufacturers, not just one brand. Even if yours is a discontinued brand or a hundred years old, our engineers have the experience to assess it and carry out the repair it needs.

Yes. We have trusted suppliers for the parts most commonly needed for DC motor repairs, including carbon brushes, brush holders, brush springs, copper strips, and commutators. This helps keep your repair moving without unnecessary delays.

Yes, call 01274 728379 day or night. A breakdown doesn’t wait for a convenient time, so emergency DC motor repair is something we prioritise as soon as you call. We’ll arrange collection straight away and keep you updated as work progresses. For critical applications, we recommend keeping a spare motor on hand to minimise downtime.

Request a Repair

Arrange a collection, drop off your motor, or speak to our engineers for technical advice on your DC motor repair.

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