What type of connection is more likely to create ferro-resonance while switching?

Ferro-resonance is a phenomenon that can occur in electrical systems due to the nonlinear characteristics of inductive and capacitive components when they are in certain configurations. The situation typically arises when there is a high inductance in parallel with a capacitance, particularly in cases where the circuit is not properly grounded.

A "floated" wye high side connection is particularly susceptible to ferro-resonance because it can create conditions conducive to this phenomenon. In a floated wye configuration, there is no direct connection to ground which means that the system can experience significant voltage fluctuations and oscillations. This lack of grounding allows for the buildup of voltages and resonances that can lead to the unexpected behavior associated with ferro-resonance.

In contrast, grounded wye connections have a direct reference to ground, which helps to stabilize the voltage and reduce the likelihood of such resonances. Delta connections do not typically create ferro-resonance as they do not have the same capacitive effects as a wye configuration. Series connections can also be stable due to their lack of capacitance and the linear nature of their voltage relationships.

Thus, it is the floated wye high side connection that is the most likely to experience ferro-resonance when switching, making