Which UPS type is no longer commonly used because it becomes unstable when connected to modern computer power loads?

Which UPS type is no longer commonly used because it becomes unstable when connected to modern computer power loads?

• A. Stand By Ferro
• B. Standby
• C. Stand By On-Line Hybrid
• D. Standby With Lithium-Ion

Answer: (A)

Stand-by ferro-resonant UPSs rely on a specialized transformer to regulate the output. This design can hold voltage steady when input conditions vary, but it does so with a fixed, sometimes narrow, load range and limited ability to respond to rapid changes. Modern computer power supplies are switch-mode and can draw current in sharp, frequent bursts with transients that change quickly as workloads shift. That quick, dynamic demand can push a ferro-resonant unit beyond its comfortable operating range, causing voltage instability or degraded performance. The combination of heavy hardware, lower efficiency, and poor dynamic response makes this type less compatible with today’s PC power needs, so it’s fallen out of common use. More current UPS designs—like line-interactive or online double-conversion—handle modern loads more reliably by delivering clean power with rapid transient response.

Stand-by ferro-resonant UPSs rely on a specialized transformer to regulate the output. This design can hold voltage steady when input conditions vary, but it does so with a fixed, sometimes narrow, load range and limited ability to respond to rapid changes. Modern computer power supplies are switch-mode and can draw current in sharp, frequent bursts with transients that change quickly as workloads shift. That quick, dynamic demand can push a ferro-resonant unit beyond its comfortable operating range, causing voltage instability or degraded performance. The combination of heavy hardware, lower efficiency, and poor dynamic response makes this type less compatible with today’s PC power needs, so it’s fallen out of common use. More current UPS designs—like line-interactive or online double-conversion—handle modern loads more reliably by delivering clean power with rapid transient response.