Harmonics and Voltage dip Analysis of Induction motor using Power Network Meter – ND45

Power Network Meter – ND45


Induction motors are the major load contributors and are also called the work horses in industries. Health of induction motors, operational efficiency and performance are necessarily monitored. Failure of these equipment due to variation in supply parameters leads to a huge loss of both production and revenue, events such as catastrophic shutdowns may also occur during events of faults. Therefore industries have made a general practise to test these equipment periodically and take corrective actions proactively. 

Problem Statement

Critical Motors which are linked to the Turbo Compressor run 24×7. There is a continuous stress on winding caused due to Harmonics and Voltage Dips, reason being unequal loading on Turbo Compressor. This results in increased heating of the induction motor which may further lead to breakdown of these critical motors.


It is crucial that the physical as well as electrical parameters of these critical motors are to be monitored continuously. Increased heating due to iron and copper losses at the harmonic frequencies cause the stress on the winding of the motor. As a number of  motors are connected in line, the switching of motors results in change in behaviour of harmonics. For example, Motor ‘A’ is ON and runs for a particular time. Due to uneven loading, harmonics are generated in Motor ‘A’. Further as we switch on Motor ‘B’ in parallel, it will also draw harmonic current. However, due to this switching, Motor ‘A’ will draw even more harmonic current compared to previous. 

ND45 – A power network recorder is an advanced multifunction instrument, which can measure various electrical parameters along with harmonics (51st) and is capable of monitoring temperature of equipment/ devices. Users can connect 2x temperature inputs to it, this helps users get a comprehensive solution of monitoring electrical parameters as well as device temperature. Temperature monitoring is essential so as to understand the heating and cooling curve of the winding and body of the equipment.

With this solution, the user is able to monitor the voltage dips event, harmonic level and the temperature of the critical motor without interrupting its operation. Promoting this, users can log this file to record the various power quality events. The status can be viewed on the device software  Power Vis or any other customer software integrated with it. 

The figure above shows a possible set-up to monitor the motor parameters using ND45. As depicted, the user can set alarm output to indicate the fault event. Also, with the available interfaces, user-friendly monitoring of the parameters can be achieved.

Other applications

  • Substation feeder monitoring
  • Logging of energy counted by other meters e.g. flow meter, gas meter, water meter or energy meter; can be done
  • Building Management System


  • This solution facilitates continuous monitoring of temperature of induction motor
  • Communication over various available interfaces enhance system automation and reliability of communication
  • User-settable output serves as a warning or cautionary signal for the given inputs
  • True visualization of Load current graph

Available features

  • Measurement and recording of over 500 electric energy quality parameters acc. to EN 50160, EN 61000-4-30 standards Class A/S
  • Analysis of current and voltage harmonics and inter harmonics up to the 51st for class I.
  • Flicker
  • 4-quadrant energy measurement in 4 tariffs
  • Monitoring up to 6 additional energy meters with pulse output
  • Recording measurements before and after events (dips and swells)
  • Configurable archives of actual values and events recording.
  • Data archiving on an SD card – memory up to 32 GB.
  • E-mail messages in case of alarm occurs,
  • Color touch screen: LCD TFT 5.6”, 640 x 480 pixels
  • Automatic synchronization of RTC clock with the NTP time server