The line-start permanent magnet synchronous motor has advantages in energy conversion with high efficiency, a power factor that can equal 1, low energy density, and the ability to start when powered. This motor meets increasingly high efficiency standards for electric motors, making it a candidate for partial replacement of the widely used induction motors. However, it has an inherent drawback common to permanent magnet motors, which is the potential for irreversible demagnetization. The main causes of irreversible demagnetization can include excessive external magnetic fields generated by the starting current, phase loss, out of step, or high operating temperatures. This paper presents a study evaluating the impact of the magnitude of the starting current on the likelihood of irreversible demagnetization. The results are based on calculations and simulations for a line-start permanent magnet synchronous motor 2.2 kW, 2p = 4. Additionally, the paper proposes a method for simulating the starting current of the motor to investigate the irreversible demagnetization process.