DC Motor

DV GROUP, the solution for your DC motors

The DC motor consists mainly of an inductor (stator), an armature  (rotor), brush holder and brushes. Its ease of use and control mean that it remains a popular type of motor for applications requiring low power consumption. Its overall cost is split between its purchase price (15%), its maintenance (35%) and its power consumption (50%).

DV GROUP offers a repair solution for all your motor types:

  • Aluminium and cast iron induction motors
  • DC motors
  • Medium-voltage motors
  • Rotor squirrel cages
  • Wound rotor
  • Explosive atmosphere (SAQR-ATEX certification)
  • Alternators from 0.02 kW to 2 MW.

Key

figures

repairs in 2017

motor repair experts

test benches

DC motor repair at DV Group

Test solutions guaranteeing 100% functional products

A variety of tools adapted to your needs:

  • Winding equipment: armature diagnosis, megaohm meter, milliohm meter, probe into motor protection: CTP/PTC/PT100, Baker Index Control.
  • Mechanic’s equipment: dimension check, ball bearing assembly using manufacturer’s specially designed tool, induction heating, machining equipment, etc.
  • Specific tools: shock wave analysis, impedance analysis, vibration measurements, balancing, mica machining machine, etc.
  • Re-magnetisation bench (permanent magnets)
  • Spare parts in stock
  • Load testing bench: DC variable speed drive up to 900 A / load on impact 1,500 A

Technical procedures / test procedures:

  • Procedure before dismantling
  • Inspect motor connectors.
  • Mechanical inspection: general condition, shaft, etc.
  • Check lubrication and evacuation ducts
  • Electrical inspection (insulation, resistance, inductors, etc.) according to the data supplied by the manufacturer.
  • Cooling control: ventilation and water circuit.

Repair Procedure

  • Metrological check of bearing seatings, joint surfaces, flanges, shaft, etc.
  • Repair: chromium plating, ringing, molten metal cladding by spraying of the various joint surfaces, complete cladding of the drive shaft
  • Electrical inspection: ageing, pollution: BAKER index, state of winding
  • Repair: winding and dip impregnated Class H: high temperature, milling of micas, brush run-in procedure

Test/validation procedure

  • Tests: no-load tests in rotation on a platform up to 1,600 kW
  • Load tests up to 600 kW at 3/4 load – 50 / 60 Hz
  • Vibration measurement and signature

Traceability procedure

  • Diagnosis and testing history
  • Traceability produced by: machine number / customer number / DV GROUP number
  • Test sheet and qualification/test certificate

Case study :

OI

Need / Context

Glass producers must rebuild their furnaces every 15 years. The refractory brick component needs to be replaced to ensure its tightness of fit. During this shutdown, the OI Manufacturing site in Ardèche refurbishes the related equipment. Glass production has a reliability requirement, and must be able to ensure long periods without breakdown or maintenance stoppage.

Solutions

To achieve these availability and efficiency goals, the glass producer entrusts us with the removal, overhaul and refitting of its fifteen 750 KW - 50 Hz medium-voltage fan and compressor motors. For one month (800 hours), our teams from the various electromechanical sites in Grigny, Cambrai and Lyon mobilised to process these products and meet the deadlines imposed by our customer. We added DV GROUP know-how to the flawless organisation demanded by this project. OI Manufacturing has atypical 750 KW - 50 Hz medium voltage motors with plain oil bearings instead of ball bearings. These bearings carry a higher radial load and have a longer life than bearings. However, they require a specific expertise.

Results

- Deadlines met - Furnace restart with products 100% tested and 100% functional

Our other solutions

for Electromechanical maintenance