AC-PRO retrofit kits are designed to replace ageing electromechanical overcurrent trip devices, thermal magnetic releases, oil dashpots, and older style electronic trip units on 600-volt class air circuit breakers. These ageing circuit breaker trip devices can jeopardize the reliability of electrical power distribution systems because they are susceptible to loss of calibration and nuisance tripping. In extreme cases, older trip units may no longer be capable of tripping circuit breakers at all during overload or fault conditions. Upgrading power circuit breakers with the AC-PRO will significantly increase power system reliability and protection while providing increased flexibility with electrical system coordination. We have several hundred complete conversion kits available in stock for air circuit breakers from: GE, Westinghouse, ITE/ABB, Allis-Chalmers, Siemens, Square D, Merlin Gerin, Federal Pacific/FPE, Sylvania, Unelec, Mears, Roller Smith, English Electric, Brown Boveri & CIE, and others. The AC-PRO trip unit is a full-function, microcontroller-based relay that is the heart of every AC-PRO retrofit kit. The trip unit is true-RMS and features a built-in 3-phase ammeter and a SELF-TEST feature that continuously monitors the trip unit, microcontroller and the actuator connection. All settings are programmed into the AC-PRO using the trip unit’s membrane keypad and 16-character LCD. Settings are input directly in amps and seconds so there are no ratios or formulas to calculate during setup. The AC-PRO also uses a programmable CT Rating which eliminates the need for a rating plug and allows the AC-PRO to be easily programmed in the field for use on any frame size circuit breaker. It is also easy to upgrade the AC-PRO to MODBUS Communications or remote current metering using the PRO-DISPLAY. Pace Technologies has the best technical and sales support in the industry. We also offer full installation and testing services for all retrofit kits.