Strange Behavior of Danfoss 155G4074 PVEH Electro-Hydraulic Actuator

This is a single-section Danfoss PVG120 with a 155G4074 PVEH electro-hydraulic actuator (proportional high with active fault monitoring) mounted on a test bench in which the main motor is driven by a generic Variable Frequency Drive. The PVEH was entering the fault mode on power-up, and, by the looks of it, it was caused by the EMI from the VFD. This is the first time I have seen this happen - I didn't manage to re-create the fault with a series 7 actuator (also with active fault monitoring) under the same conditions. Unfortunately, I do not have another series 4 PVEH to try this out... In any case - I'll remember that a VFD can affect a PVE actuator and that proper grounding/shielding is a solution. I can totally see how this scenario could lead one to replace an expensive and perfectly functional component. A more detailed description of the test at https://www.insanehydraulics.com/batt...