Abstract: Based on the working principle, electromagnetic relationships, and characteristics of a three-phase asynchronous motor under short-circuit locked-rotor conditions, this paper establishes the electromagnetic change law and mathematical model of the motor under short-circuit locked-rotor conditions, thereby conducting a simulation study on the short-circuit locked-rotor test of the three-phase asynchronous motor. This paper provides a theoretical basis for conducting short-circuit locked-rotor tests. Keywords: Three-phase asynchronous motor; Mathematical model; Simulation; Hold-up and Stop-up Rotating Abstract: Based on the theory of three different-step electrical machines, the electromagnetic relationship, and the characteristics of holding up and stopping up rotating, this article establishes the electromagnetic laws and mathematical model of holding up and stopping up rotating, and uses emulation to study the experiment of holding up and stopping up rotating in three different-step electrical machines. This article provides the basis for the experiment of holding up and stopping up rotating. Keyword: Three Different-Step Electrical Machines; Mathematics Model; Emulation; Hold-Up and Stop-Up Rotating 1. Introduction The short-circuit locked-rotor test is an effective method in engineering to determine the short-circuit impedance XK and RK. During the test, the rotor winding is short-circuited, and the rotor is locked, preventing it from rotating. It should be noted that if the rated voltage is still applied to the rotor at this time, the current will be several times the rated current, which is obviously not allowed. Therefore, the short-circuit locked-rotor test must be run under low voltage. For details, please click: Application of MATLAB in Short-Circuit Locked Rotor Test of Three-Phase Asynchronous Motor