Permanent magnet motors (PMMs) can develop oscillations during motor startup that can cause damage to electric submersible pump (ESP) components. A system and method are presented for identifying mechanical and/or electrical caused oscillations in a PMM through the analysis of oscillations in current and torque measurements. A control system within a surface motor controller receives current and/or torque measurements from downhole sensors. The control system employs one or more algorithms designed to detect oscillations in the measurements. Upon detecting oscillations that are consistent with oscillations in the motor from mechanical or electrical causes, the control system automatically initiates protective action to prevent damage to the ESP components.