How does surge protection at the input and output of a ferroresonant power supply defend against voltage surges?

Surge protection at both the input and output of a ferroresonant power supply defends against voltage surges primarily by passing voltage surges to ground without damage. This mechanism works by providing a path for excess voltage to be safely redirected away from sensitive components and into the ground.

When a voltage surge occurs, such as from a lightning strike or a sudden change in load, the surge protection devices detect this abnormal rise in voltage. They then act to shunt this excess voltage to the ground, thus protecting the circuitry of the power supply and any connected equipment. This is critical because it ensures that the internal components of the power supply are not exposed to damaging levels of voltage that could lead to failure or reduced lifespan.

While rerouting surges to a secondary circuit might seem plausible, it doesn't sufficiently address the need to safely ground excess voltage. Increasing the voltage capacity of the supply would not be a defensive measure against surges, as that would not mitigate the risk. Disconnecting the supply during surges could lead to interruptions in power delivery and may not always be practical or effective in protecting equipment from damage. Therefore, the primary and most effective method utilized by surge protection in this context is indeed the safe diversion of surges to ground.