Electrical Machine Black Box

Electrical Machine Black Box (EMBB) is an innovative solution that places focus on key information important to machine users. Conventional monitoring systems for rotating machines are based on the vibration measurement with the purpose to record measuring data and to alarm the user when the measured value reaches the pre-set value.

While these systems often require expert analysis and a large amount of data to draw conclusions, EMBB is a smaller and simpler solution that provides specific information about the state of the machine directly to system users, without the need for detailed and expert analysis of the collected data. 

Instead of providing users with detailed machine information, EMBB shows only issues that are seen by personnel after machine failures or problems occur. Plant staff normally has to pay attention to many different data sources and this makes it sometimes hard to focus on areas with higher priority.

EMBB therefore reacts and displays information only when errors and problems appear, that is, it tracks how machines are operated and point out which unusual actions caused the machine to experience failure. This is especially important for top management and plant supervisors that need to increase production time, cut down the maintenance cost, and find out the reasons behind the machine failures.

Main issues detected

  • Asynchronous operation 

    This occurs if excitation current is terminated in the machine that is loaded and connected to the power grid. The rotating magnetic field changes direction, the machine shifts from a generator to motor operation causing extremely high currents in the stator winding. The amplitudes of these currents may be similar to those in short circuit, which represent risks to a machine lifetime.

  • Incorrect synchronization

    A condition that can occur during machine and power grid merger. The result is a failure to fulfill all the rules of synchronization.

  • Significant asymmetry 

    This implies the difference between phase currents which are larger than those specified by machine characteristics or by the contract.

  • Two-phase operation

    Represents a situation in which two phases of stator winding are loaded while the remaining third phase is unloaded. This condition represents significant asymmetry and significantly influences machine lifetime.

  • Run-out 

    The machine speed exceeded the rated speed of rotation. This parameter is defined separately for each machine, depending on the type of turbine, regulation protection, and implementation project. A number of run-outs significantly affect machine lifetime.

  • Overloading 

    A machine condition where the stator current is above the rated or those agreed with the contract.

  • Overheating 

    Overheating of stator/winding iron may be a result of overloading or operation during a machine fault. The boundaries are defined by the standards and for each machine in its implementation phase.

  • Extensive vibrations 

    The same as with overheating, the extensive vibrations may be a result of overloading or operation during a machine fault. This is also regulated with standards.

Technical overview

  • Architecture: Data acquisition unit with the real-time controller
  • Inputs:
    • Three voltage inputs for stator voltage measurement (0-500 V)
    • Three current inputs for stator currents measurement (1A/5A)
    • One voltage input for excitation current measurement (0-10 V)
    • One voltage input for speed measurement (0-10 V)
    • Two RTD (pt100) or thermocouple inputs
    • Two vibration inputs (IPE)
  • Digital/relay outputs:
    • Number of outputs: 2 to 8
    • Continuous current: 6 A
    • Maximum switching power: 1500 VA
    • Maximum switching voltage: 250 VAC/DC
    • Maximum switching frequency: 0,1 Hz
    • Rated isolation voltage: 300 V overload (category III) by EN 50178
    • Surge withstand: 4 kV (1,25/50 µs), by IEC 5017
  • Communication:  Ethernet 10/100
  • Power supply:
    • DC: 80 V to 370 V
    • AC: 85 to 264 V, frequency 47 to 63 Hz
    • Maximum allowed power supply interruption: 100 ms for 230 VAC/ 20 ms for 115 VAC
    • Test voltage: 3 kV (2 kV against the ground)
  • Temperature range:
    • Operational temperature range: -20°C to +70°C (storage temperature: -40° to +85°C)
  • Standards compliance:
    • EMC immunity/emission: EN 61326-1 (IEC 61326-1:2005), EN 61000-3-2+A1+A2 (IEC 61000-3-2+A1+A2), EN 61000-3-3 (IEC 61000-3-3), EN 61000-4-10+A1 (IEC 61000-4-10+A1), EN 61000-4-12 (IEC 61000-4-12), EN 61000-4-18+A1 (IEC 61000-4-18+A1)
    • Vibration/shock resistance (EN 60068-2-6/EN 60068-2-27/29)


  • identification of operating procedures that are harmful to the machine
  • protection against improper machine operation during the warranty period
  • provides key information (corrective measures) for machine life cycle extension and effective asset management
  • designed for harsh conditions and environments
  • flexible topology and simple configuration
  • Standard industrial communication (EtherCAT)

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