Appendix A: Transient Protection
AC Power Line Transient Protection
In the process of power distribution, transient electrical energy (including, but not limited to, lightning strikes, intermittent short circuits, and switching transients) can be introduced onto power lines. Such transient energy can be very damaging to electronic hardware, and can also cause data corruption. Under these circumstances, NCR recommends the use of AC power transient suppressors. Such protection devices are intended to guard against power line transients that can result in hardware damage and various system or program errors.
Improvement of any deficiencies in power quality is a customer responsibility. Malfunction and/or component failure as a result of power quality problems is not covered by the NCR Maintenance Agreement. NCR accepts no liability for any such occurrence or for its consequences.
When power transient suppression is required, the suppressors used should meet the following minimum requirements:
•Dissipate energy to match the appropriate application categories as defined by IEEE Standard 587.
•Be of the voltage limiting (clipping), or tracking filter type. The suppressor must not clamp the voltage to zero, and must self- recover after the passage of the transient. The suppressor may be of the hybrid type construction that makes use of various technologies in order to meet speed and dissipation requirements.
•Upon failure, exhibit a positive indication of its failure such as a blown fuse or tripped breaker.
