The EPR units provide surge and spike suppression, noise reduction and power factor correction for 120Vac single phase to 600Vac three phase commercial applications. The EPR unit is placed in parallel into AC systems either at the main power panel for a facility or at sub panels within the power distribution system. In many cases it is placed on individual equipment such as large induction motors and HVAC equipment. The EPR is placed on the load side of a main breaker to reduce KVA and KWh consumption and secondarily is used also as a TVSS (Transient Volt Surge Suppressor).

Surge and spike protection is achieved through Metal Oxide Varistors (MOV’s), which consist of two plates of metal surrounded by ceramic material. The ceramic material channels additional current and stops the voltage increase at a low enough level to prevent damage to equipment, acting as a short circuit. Under normal conditions the ceramic material does not conduct electricity. MOV’s can respond to provide protection in as little as TEN (10) NANOSECONDS (ten millionths of a second). The EPR provides complete clamping voltage; hence, total surge rating occurs within 8/20 usec 40 to 100K amps. The total energy absorption capacity, in joules, is approximately 1800 for single-phase units and 2700 for three-phase EPR’s. The varistor ratings are listed on the following page.

Noise suppression is achieved by the different capacitances within the EPR’s. The Metal Oxide Varistors (MOV’s), which also provide surge suppression, help in noise suppression. The primary power factor capacitors also provide noise suppression and general line conditioning. Smaller line to ground capacitors are installed in the units to provide low impedance to high frequency noise.

Power factor correction for inductive loads is provided by the primary capacitors. These primary capacitors range from smaller metalized polypropylene caps installed line to line to oil field polypropylene can type capacitors wired into a special U.S. patent pending configuration for the three phase EPR’s. Real Kilowatt savings of from 8% to 20% are the usual results realized after installation of the EPR’s.