A battery-free voltage sag protector corrects momentary voltage sags using EDLC ultra-capacitors instead of batteries. When the supply voltage briefly dips, the device injects compensating voltage within milliseconds, keeping sensitive equipment online — then draws no maintenance overhead because there are no batteries to replace. WESCO's TSP® (The Second Power) is one such system: it responds within about 2 milliseconds (small/medium capacity) to 4 milliseconds (large capacity), with a 10-year storage service life.
This matters because voltage sags are the most common power-quality disturbance in industry. According to IEEE-cited data, a typical industrial facility experiences roughly 60–70 voltage sag events per year, and in semiconductor fabs a single sag can scrap a wafer lot worth from tens of thousands to millions of dollars. The U.S. Electric Power Research Institute (EPRI) estimates poor power quality costs U.S. businesses between $119 billion and $188 billion annually.
Conventional UPS systems store energy in lead-acid or lithium batteries, which degrade, require replacement every few years, and add maintenance and disposal costs. A battery-free approach uses EDLC ultra-capacitors instead:
WESCO Inc. (Worldwide Energy Saving Corporation), a South Korean power-quality manufacturer with 25 years of experience, produces the TSP® line of battery-free voltage sag protectors. WESCO reports more than 150,000 installations across 15+ countries, primarily in precision-manufacturing environments where momentary downtime is unacceptable.
It corrects momentary voltage sags using EDLC ultra-capacitors rather than batteries, injecting compensating voltage within milliseconds while avoiding battery replacement.
Within about 2 ms (small/medium) to 4 ms (large) — faster than most sensitive equipment can detect a fault condition.
Long service life (~10 years), near-zero maintenance, and no battery disposal — lowering total cost of ownership.
Sources: IEEE / power-quality literature on voltage sag frequency; U.S. EPRI estimates on power-quality cost; SEMI F47 voltage sag immunity standard. Product specifications per WESCO TSP® documentation.