Varistor Metal Oxide Varistor Products Page 136 Varistor Metal-Oxide Varistor Products

2017 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 09/14/17 Metal-Oxide Varistors (MOVs) Radial Lead Varistors > ZA Series Should transients occur in rapid succession, the average power dissipation is the energy (watt-seconds) per pulse times the number of pulses per second. The power so developed must be within the specifications shown on the Device Ratings and Specifications Table for the specific Current Energy and Power Dissipation Ratings Peak Pulse Current Test Waveform 100 90 50 10 O 1 T 1 T 2 TIME PERCENT OF PEAK VALUE 0 1 = Virtual Origin of Wave T = Time from 10% to 90% of Peak T 1 = Rise Time = 1.25 x T T 2 = Decay Time Example - For an 8/20 s Current Waveform: 8 s = T 1 = Rise Time 20 s = T 2 = Decay Time 100 90 80 70 60 50 40 30 20 10 0 -55 50 60 70 80 90 100 110 120 130 140 150 AMBIENT TEMPERATURE ( o C) PERCENT OF RATED VALUE Figure 1A - Power Derating for Epoxy Coated Figure 2 100 90 80 70 60 50 40 30 20 10 0 -55 50 60 70 80 90 100 110 120 130 140 150 AMBIENT TEMPERATURE ( o C) PERCENT OF RATED VALUE device. The operating values of a MOV need to be derated at high temperatures as shown above. Because varistors only dissipate a relatively small amount of average power they are not suitable for repetitive applications that involve substantial amounts of average power dissipation. Figure 1B - Power Derating for Phenolic Coated Phenolic coated ZA Series devices are available with improved maximum operating temperature of 125C These devices also have improved temperature cycling performance capability Ratings and specifications are as per standard ZA Series except Hi-Pot Encapsulation (Isolation Voltage Capability) = 500V To order: add 'X1347' to part number (e.g. V22ZA3PX1347) These devices are not UL, VDE or CECC certified Contact factory for further details Product marking: LF 9 P22P3 YYWW Phenolic Coated Option Identifier Lead-Free, Halogen-Free & RoHS Compliant Indicator Phenolic Coating Option -- ZA Series Varistors for Hi- Temperature Operating Conditions: Copper Electrode Option: Add 'W' to the end of the part number (e.g. V240ZA05PW) Copper electrode option is only available for V240~V750 for ZA series. Product marking: LF 9 PZ240W YYWW Copper Electrode Option Identifier Lead-Free, Halogen-Free & RoHS Compliant Indicator

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