

Transient Motor Starting
Analysis
The Transient Motor Starting
Analysis module (TMS) is a stateoftheart time simulation
program to analyze all aspects of motor starting problems accurately.
TMS models up to 1500 motors
dynamically throughout starting, stopping or reacting to load changes.
In order to completely examine motor starting problems, TMS has the
capability to dynamically represent motors which are already on line at
the beginning of the simulation.
The complete network is
continuously modeled throughout the time simulation in order to
properly represent the interactions between motors and to be able to
examine the effects of static loads, transformer taps, generator
voltage setpoints, and all other network parameters.
Benefits:
 1. Quickly examine and evaluate motors in your
system for a variety of situations including; group motors starting,
motor starting with different system load
configurations, motor start heating problems, and evaluation of up to 9
motor starter types for reduced voltage
starting schemes.
 2. Design efficient systems by determining
optimal timing of staggered motor starting and reacceleration schemes.
 3. Customize solutions with adjustable source
voltage, include/exclude utility source equivalent impedance, and user
definable time step for analysis.
 4. Communicate designs effectively with
professional graphics and reports.
TMS Output:
 Bus voltage
 Motor voltage
 Motor rotor current
 Load torque
 Motor speed
 Motor stator current
 Motor torque
 Accelerating torque
 Motor slip
 Reactive power (kVAR)
 Power factor
 Real power (kW)
 Total power (kVA)
Features:
 Compare alternative designs graphically on a
single plot.
 Analyze torque speed characteristics of motors
in actual system operation.
 Analyze motor load changes.
 Determine voltage dip impact of motor starting.
 Determine motor accelerating times.
 Create user defined graphical data for loads
and motors.
 Includes typical models for pumps, fans,
compressors, grinders, blowers, and MG sets.
 Evaluate the interaction between multiple
motors during starting conditions.
 Evaluate motor starting with different system
load conditions and network configurations.
 Evaluate motor starting heating problems (l2t).
 Evaluate application of reduced voltage
starters.
 Determine the optimal timing of staggered motor
starting and reacceleration schemes.
 Determine the impact of motor starting on other
online motors.
 The time related output data includes: bus
voltage, motor speed, motor slip, motor torque, load torque,
accelerating torque, stator voltage, stator current, input power, VARs,
power factor, and rotor current.
 Time and voltage dependent switching is
provided to start or trip motors or to enact motor load changes.
 Switch motors based on group and priority in
motor group acceleration setup.
Motor Starter Options:
 Series resistance
 Series reactance
 Solid state, current limit
 Solid state, voltage ramp
 Solid state, current ramp
 Full voltage
 Auto transformer
 Part winding
 Stardelta
 Shunt capacitors
Solution Modeling:
 Models stator and rotor circuits of multiple
motors with the entire system network in order to model interaction
between motors.
 Load models include torquespeed equations for
fans, pumps, linear functions of speed, and user specified torque speed
curves.
 Utilizes a load flow solution to model multiple
motors within the full network for each time step.
 Network may include any combination of constant
kVA loads, constant current loads, and constant impedance loads as well
as generators which can schedule power and voltage within VAR limits.
