What is a Transient Motor Starting Study?

In our ongoing series exploring the most frequently conducted consultancy studies at EPS, we now delve deeper into Transient Motor Starting Studies.

Transient Motor Starting studies are an important aspect of power system analysis and design. They help to identify potential issues and problems that may occur during the starting and acceleration of electric motors and can help to mitigate or prevent these issues from causing damage or downtime.

Electric motors can experience significant voltage and current transients during starting and acceleration. These transients can cause damage to the motor, as well as to other equipment connected to the same power system. Additionally, these transients can cause power quality issues, such as voltage dips and transients which can disrupt the operation of other equipment connected to the power system.

Benefits of Transient Motor Starting Studies

Transient motor starting studies can help to identify and mitigate these issues by analysing the power system and determining the causes of the transients. This can include identifying the types of motors and loads connected to the power system and the power system’s configuration and protection devices. The study can also help to identify the best ways to start and accelerate the motors to minimise the impact of the transients.

Another important aspect of transient motor starting studies is that they can help to ensure the safe and reliable operation of the power system. For example, the study can help to identify potential safety hazards and equipment failures that may occur during motor starting and can help to develop appropriate mitigation strategies.

Our Approach to Transient Motor Starting Studies

At EPS, we regularly carry out Transient Motor Starting (TMS) studies to analyse the electrical and mechanical behaviour of motors during the starting and acceleration process. A reliable and accurate understanding of these transient behaviours is crucial for the safe and efficient operation of electrical power systems.

To carry out a TMS study, we use a software program called ETAP or DIgSILENT. Both ETAP and DIgSILENT are comprehensive software programs for the design, analysis, and operation of electrical power systems. Either software allows us to model and simulate various scenarios and conditions and provides a range of tools and features for analysing the resulting data and making informed decisions on what starting methods and what protection schemes should be installed.

To begin a TMS study using ETAP or DIgSILENT, we first set up a model of the electrical power system, including all the relevant components and parameters such as generators, transformers, loads, and motors. We then define the starting and acceleration scenarios that we want to analyse, including the initial conditions of the system and the starting and acceleration characteristics of the motor.

Once the model and scenarios are set up, we next run simulations and analyse the resulting data. This includes calculating the current, voltage, and power flows through the system, as well as the speed and torque of the motor. By analysing this data, we can understand the transient behaviours of the motor and make informed decisions about the operation of the electrical power system during motor starting.


Transient Motor Starting Studies help to ensure the safe and reliable operation of electric motors and other equipment connected to power systems. Our highly experienced Engineers are here to assist you in securing your electrical network when installing large or medium-sized motors. If you have any concerns or questions, please do not hesitate to contact us for guidance.

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