I am quite certain that the power supply did not fold back during any of the above testing. Data is always better than speculation.
These traces were taken using a single channel of the QPX600DP at its maximum current and set to 13.8V (limit is thus 43.4A). I command a 0-50% voltage-controlled step and watch the results. Output shaft is unloaded (at startup rotor inertia is a perfectly suitable load, plus I never had load on the shaft at startup in my earlier testing). Red is DC bus current, blue is bus voltage at the Jaguar terminals. Trigger is on bus current rising over 10A.
Startup, long view
Startup, medium view
Startup, close up of voltage rail
Startup, gate drive
Gate drive is measured with an
Agilent N2790A differential probe.