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Electrical rotating machine
DEKRA Industrial Inspection

Using the latests robotics technologies to increase efficiency, prodcutivity and reliability

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Electrical motor and generator inspection

Testing with rotor-in-situ technology

Turbo and Hydro generators as well as large motors are crucial components in an industrial power plant and are designed to operate reliably for many years. One of the most expensive parts of a 3-phase generator is the stator, which is where the energy from the magnetic field is converted into electrical energy/ mechanical energy. The condition of the stator core of a rotating electrical machine deteriorates over time, increasing the likelihood of failures. Quantitative testing and periodic inspections of the generator core are necessary to avoid outages.

The common trend is to inspect the generator during a minor outage with the rotor in-situ. This has a big advantage as it is less labor intensive and is associated with lower cost compared to removing the rotor. Aside from saving time and money during an outage by inspecting with the rotor in place, the results allow for planning of a major outage (e.g. ordering components with a long lead time). Reduced disassembly requirements during the overhaul means less people on site, higher availability of crane and more lay-down space. Possible consequential damage due to rotor dismantling is avoided.
Electrical motor and generator inspection services
Regular testing increases reliable operation and prevents potentially costly downtime and repairs. Our experts can provide you with information and recommendations regarding:
  • Condition of the Turbo generator/ Hydro Generator / Large motor
  • Routine maintenance/overhaul
  • Long-term condition
If you have any other requirements, like eddy currents testing of Turbo generator coolers, UT/PAUT on rotor wedges (for built-out rotors), NDT on fan blades, bearings or other, please get in touch.

Measurements, inspections and testing

    • Ohmic phase resistance.
    • Polarization index and insulation resistance on each phase of the stator winding.
    • Charge/discharge measurement of the stator winding.
    • Overvoltage DC test, also referred to as high-potential or DC hi-pot tests.
    • Tan Delta measurement on each phase and capacitance test.
    • DC leakage test.
    • Partial discharge measurements.
    • Visual inspection of end-windings, winding connections, support system of end winding phase and series caps and ties.
    • Visual inspection of terminal area: bushings, lower leads, stand-off insulators, connection to the bus ducts.

    Online guidance session

    Would you like to know how we can help you with our electrical motor and generator inspection services? Please get in touch! During a free online session you can ask specific questions to our expert and we will guide you through the process. Complete the form below. We will call you back at a time of your convenience.