NEPLAN | Motor Starting

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This module computes the motor start-up in unlimited networks and offers the possibility of simultaneous or time-delayed start-up for any desired number of motors. Motor Starting module can simulate different motor models, depending on the motor data entered and it also allows for start-up devices, such as star-delta starter, series resistor, transformer, soft starter, etc.

General Characteristics

  • Identification of motor parameters using the least square method from input values for torque, current and cos(phi) in function of the slip
  • Saturation and eddy-current losses in the motor allowed for (linear or point-by-point)
  • Libraries for standard motor data, plus additional extendable libraries for Me(s), I(s) and cosphi(s) are available
  • Operating point computation for all non-starting motors in accordance with their load characteristics (Newton-Raphson)
  • Automatic tap changing transformers are allowed for after a user-defined time-delay
  • Load torque entered as a characteristic or as a linear or quadratic load torque curve
  • Extendable Libraries for load torques are available

Voltage Drop

This option calculates the voltage drop at time t=0.0 due to starting motors, thus less motor data and computation parameters have to be entered. Non-starting motors can be simulated by a user-defined load PQ (constant power) or shunt. Results of Voltage Drop Calculation are easily accessible:

  • Overloaded elements, measuring instruments and protective devices or nodes with voltages outside a defined range are highlighted
  • Results of the voltage drop computation are displayed in the single line diagram
  • The motor data entered and the motor parameters computed can be accessed by clicking on the motor concerned in the single line diagram


Results contain information on preselected nodes and elements. Also, graphical output of the characteristic curves and time characteristics is provided. Results display (dimensioning, scaling, colors etc.) can be customized.

  • Computation of voltage U(t) at predefined nodes and of l(t), P(t), Q(t) for predefined elements
  • Computation of motor current I, load torque M, electromagnetic torque Me, active power P and reactive power Q as functions of time, or of the slip for starting-up and non-starting-up motors
  • Result lists can be saved in text files
  • Results can be saved in result files for evaluation by means of spreadsheet programs (such as MS-Excel)