The EZAUVR200AC is an undervoltage release (UVR) from the EasyPact GoPact range, designed for EasyPact EZC100 and EasyPact CVS100BS molded-case circuit breakers. It drops the breaker when the control voltage falls below the 0.35...0.7 Un operating threshold and closes once voltage returns above 0.85 Un.
The 50 ms response time governs how fast the release acts on a voltage dip; for motor circuits or process lines where a sag below 70% of nominal needs a fast trip, that figure tells you the breaker opens within two mains cycles.