Abstract
Accelerating time–current (ATC) curves of induction motors are normally used for setting, selecting, and coordinating their overcurrent protective devices against heating. Conventionally, the ATC curves can be computed using commercial software tools via a dynamic simulation. This approach always needs a completed set of motor circuit-model parameters, which are typically unavailable to users. To eliminate this problem, this article addresses a direct approach to calculate the ATC curves from commonly available manufacturer data sheets of motors without using the sophisticated simulation tool. Mathematical models of motor’s torque and current curves, taking a nonlinear deep-bar effect into account, are proposed for the ATC determination. The computed torque and current profiles are validated by comparison with those generated from the Matlab simulation tool, published equivalent-circuit parameters, and field measurements. An accuracy of the obtained ATC curves is also assessed against those of the dynamic simulations. The satisfactory results are entirely obtained.
DISCLOSURE STATEMENT
No potential conflict of interest was reported by the author(s).
Additional information
Funding
Notes on contributors
![](/cms/asset/ce937eec-1c9c-4f5f-a887-aab7d3cbc897/tijr_a_1997360_ilg0001.gif)
P. Aree
Pichai Aree received MSc in electrical power engineering from the University of Manchester Institute Science and Technology (UMIST), England, in 1996, and Ph.D. degree in electrical engineering from the University of Glasgow, Scotland, in 2000. He joined Department of Electrical Engineering, Thammasat University, Thailand in 1993. He is currently an associate professor at Department of Electrical Engineering, TU. His research interests are power system modeling, dynamics and stability Email: [email protected]