How ODES UEG/I DC current relays distinguish real coil operation from virtual voltage and transient spikes Why Voltage-Only Logic Is Not Enough in DC Control Circuits In DC trip and close circuits, engineers face three recurring headaches at the same time: High inrush current when a trip or close coil is energized Short-duration DC bus dips and ripple during switching events Long control cables that pick up induced transients and create “virtual voltage” If the supervision