Eaton ESF801-TN-E Surge Suppressor/Protector

Functional Description

The ESF series surge filters are Class II, single and three phase, 2 port SPDs, designed to provide complete site surge protection in a compact footprint. These models utilize UL1449 ed3 certified thermally-fused MOV devices in conjunction with air-wound inductors to provide a currentlimited output, coordinated to surge levels below 3kA. This means that all downstream power circuits are protected to ANSI/IEEE C62.41 Category B level, the common level that medium power LV loads (UPS, rectifier, industrial machines) are designed to accept. The design results in an exceptionally low let through voltage. ( <600V, 3kA, 8/20us ). In addition, the units also provide filtering of line harmonics, noise and RF transmitters with a cut off frequency of <10KHz and a nominal attenuation of 48dB above 1MHz.

The units can be supplied in gear-tray format for installation into a switchboard, or enclosed in an IP54 enclosure. When installed in compliance with the manufacturer's instructions and applicable standards, this unit provides a high degree of protection to connected loads. Models are offered in 1 or 3 phase for TT or TN-based power systems in the range of 50A to 80A.

Principle of Operation

Excess potentials are captured by the primary protection stage, resulting in a protection level of <600V @ 3kA, (8/20us) and <800V @ 50kA, Inom (8/20us). The filter components reduce rise-time of the remaining surge and control current to the secondary MOVs. A 'Low Q' filter design is utilized to avoid resonance effects. When the secondary MOVs conduct, the unit's output is clamped and the inductor provides current-limiting of the surge into the externally-connected load circuits. TN models use Neutral as the primary and secondary surge return paths and provide Neutral-Earth protection via a high-energy gas arrestor. TT models use Earth as the primary surge return and Neutral as the secondary surge return path. TT models use MOV devices for Neutral-Earth protection. These units are applicable to TT, TN-C, TN-S and TNC-S power systems nominally rated between 380 and 440V.