2722 Current Unbalance Detector from Time Mark
The Model 2722 Current Unbalance Detector is designed to monitor 3-phase AC current (or compare three single-phase AC currents).
A solid-state electronic sensing circuit drives an internal DPDT relay which energizes during normal, balanced conditions. An unbalanced condition will cause the relay to drop out.
The Model 2722 accepts current inputs up to 5 amps and will consider zero amps as balanced (relay stays energized), making the device suitable for use with 3-phase heaters.
The Model 2722 has adjustments for percent of unbalance and time delay before tripping. It will automatically reset upon restoration of correct current balance, or a normally-closed momentary switch can be connected for a manual reset. External CT's can be used to extend the operating current range.
Time Mark Corporation