Varistor Metal Oxide Varistor Products Page 181 Varistor Metal-Oxide Varistor Products

2017 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 09/14/17 Metal-Oxide Varistors (MOVs) Industrial High Energy Terminal Varistors > HA Series Should transients occur in rapid succession, the average power dissipation required is simply 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 device. Furthermore, the operating values need to be derated at high temperatures as shown in above. Because varistors can only dissipate a relatively small amount of average power they are, therefore, not suitable for repetitive applications that involve substantial amounts for average power dissipation. Power Dissipation Ratings 100 90 80 70 60 50 40 30 20 10 0 -55 50 60 70 80 90 100 110 120 130 140 150 PERCENT OF RATED VALUE AMBIENT TEMPERATURE ( o C) 100 90 50 10 O 1 T 1 T 2 TIME PERCENT OF PEAK VALUE Peak Pulse Current Test Waveform Maximum Clamping Voltage for 40mm Parts V111HA40-V751HA40 Maximum Clamping Voltage for 32mm Parts V111HA32-V751HA32 100 1000 10000 0.001 0.01 0.1 1 10 100 1000 10000 100000 Current (A) Voltage (V) TA = -55 C to 85C V681CA32 V751CA32 V481CA32 V441CA32 V421CA32 V391CA32 V571CA32 V661HA32 V551CA32 V511CA32 V301CA32 V331CA32 V321CA32 V351CA32 V271CA32 V251CA32 V201CA32 V181CA32 V151CA32 V141CA32 V131CA32 C111CA32 Maximum Clamping Voltage HA32 Series 110 to 750V AC Rating Current , Energy and Power De-Rating Curve 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 1000 10000 0.001 0.01 0.1 1 10 100 1000 10000 100000 Maximum Clamping Voltage HA40 Series 110 to 750V AC Rating TA = -55 C to 85C Current - (A) Voltage(V) V751 V571 V551 V511 V481 V441 V421 V391 V351 V111 V131 V141 V151 V681 V331 V321 V301 V271 V251 V201 V181 V661 Figure 1 Figure 2 Figure 3 Figure 4

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