National Electric Motor Services

Site Service

Our teams excel in site work by implementing effective preventative maintenance programs that encompass thorough field inspections and maintenance schedules. These programs are especially valuable for motors that cannot be easily or economically transported to workshops for servicing.

To ensure efficiency during site work, our approach is based on extensive maintenance experience, specialised tools, and in-depth product knowledge. This expertise enables us to accurately determine the required maintenance level and scope, whether it’s predefined based on time or assessed in conjunction with the observations of our skilled service technicians.

By combining our dedication to safety with our comprehensive maintenance strategies, we consistently deliver exceptional results in the field. Our commitment to a safe working environment remains a top priority, and it is the cornerstone of our success in providing reliable site maintenance solutions for our clients.

Motor Maintenance

         Motor Stopped:

  • Disconnect and reconnect termination cables
  • Dismantle and reinstallation of DE and NDE end covers
  • Extract rotor out from stator (if required)
  • Reassembly of machine (if required)
  • Visual inspection on foundation, stator external, main and aux termination, heat exchanger and other accessories
  • Visual inspection on windings, slots wedges, lead joint, bracing.
  • Visual inspection on commutator and carbon brushes for DC machines
  • Visual inspection on slip ring and carbon brushes for slip ring machines
  • Replacement of anti-friction bearings or inspection of sleeve bearings.
  • General cleaning within terminal compartments.
  • Complete cleaning on windings with dry ice, fresh water or solvents
  • Bake dry with portable heating ventilation system
  • Static electric test on windings and accessories
  • Bearing fitting clearance check

         Motor Running

  • Record and review machine running parameters
  • Vibration measurements
  • Report submission
Motor Management

Motor Management – Operational

  • Spare parts covering the basic spare part need during commissioning and the first few years of operation.
  • Consumable, wear and tear parts.
  • Usually, parts can be replaced without dismantling the machines completely.

         Example of operational spares:

  • Space heaters
  • Terminal box insulators
  • Stator RTD kits
  • Vibration sensors
  • Built in transformers
  • Leakage water detector
  • Heat exchanger
  • Slip rings
  • Bearing parts
  • Bearing temperature sensors
  • Tachometer
  • Brushes and brush holders


         Motor Management – Capital

  • Large components with long delivery times.
  • Significant impact on downtime.
  • For reduced downtime in critical applications.
  • Large investment – risk analysis for down time to be made by customer.

         Example of capital spares:

  • Complete stator
  • Complete rotor
  • Complete motor

Testing and Commissioning Electric Motors

         Motor Inspections

  • Site Diagnostics and measurements
  • Drive train analysis
  • In situ commutator, slip ring and brush-holder refurbishment.
  • Surface re-conditioning
  • Mica undercutting (commutators)
  • Bar edge chamfering (commutators)
  • Troubleshooting applications
  • Carbon brush survey
  • Helical groove edge chamfering (slip rings)
  • Out-of-round machining
  • Carbon brush pressure measurement
  • Redesign for carbon brush, brush-holder and commutator / slip ring system
  • Installation of features to improve the performance of your machines
  • Remote and wireless carbon brush wear monitoring (See i-Brush 1.1 System)
  • Dust extraction solutions
Electrical Testing

Elec Motor Commissioning

Electrical Testing

Field service static testing programs are commonly used for carrying out in depth analysis on the winding condition of electric motors, especially for machines for which it is not economical or practical to be removed for workshop service.

Inspection and maintenance scope is based on vast maintenance experience, dedicated electrical testing tools and product knowledge.


  • Visual inspection
  • Symmetry Tests Including:
    – Resistance
    – Impedance
    – Inductance
    – Phase Angle
    – Capacitance
    – Insulation Resistance
    – IF Current/Frequency
  • Step Voltage
  • Polarisation Index
  • Tan Delta
  • Partial Discharge (PD)

Rotor (if applicable):

  • Symmetry Tests
  • Polarisation Index

Armature (if applicable):

  • Insulation Resistance
  • Bar to bar impedance and resistance
  • Bar to ground

Brands that we service and repair

Site Service Enquiries

Product Enquiry