Sags - Effect on Data

Like all sags, externally-based sags result from load changes and system impedance. In this case, however, the customer has little or no control over the problem. As far as the customer is concerned, the source voltage at the service entrance dipped.

When a sag occurs, a device's power supply uses some of its stored energy to compensate for the loss of input voltage. If enough energy is lost due to the sag, the power supply may lose its ability to maintain an exact DC voltage to all the integrated circuits inside the device - even for a few milliseconds. This is enough to lose or corrupt data.

Some form of voltage regulator or energy storage device is needed to remedy these types of disturbances. Products that provide longer ride-through times such as enhanced power supplies, that regulate the voltage such as tap-switching conditioners, or that switch to temporary back-up power like an SPS, will suffice.