Harris LA Varistor Series Test Results / Test Reports
Power Dissipation Ratings
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
device.The operating values of a MOV need to be derated
at high temperatures as shown in the diagram below.
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.
Current Energy and Power Derating Curve
Peak Pulse Current Test Waveform
100
90
50
PERCENT OF PEAK VALUE
10
Figure 2
O
1
T
T
1
T
2
TIME
Figure 1
100
90
80
70
60
50
40
30
20
PERCENT OF RATED VALUE
10
0
-55 50 60 70 80 90 100 110 120 130 140 150
AMBIENT TEMPERATURE (
o
C)
01 = Virtual Origin of Wave
T = Time from 10% to 90% of Peak
T1 = Rise Time = 1.25 x T
T2 = Decay Time
Example - For an 8/20 μs Current Waveform:
8μs = T1 = Rise Time
20μs = T2 = Decay Time
LA Varistor Series
114
Revision: January 9, 2009
©2008 Littelfuse, Inc.
Please refer to www.littelfuse.com/series/la.html for current information.
Specifications are subject to change without notice.
Transient V-I Characteristics Curves
Pulse Rating Curves
Maximum Clamping Voltage for 7mm Parts
V130LA1(P) - V300LA2(P)
6,000
MAXIMUM CLAMPING VOLTAGE
5,000
MODEL SIZE 7mm
4,000
130 TO 300V
= -55oC TO 85oC
T
3,000
A
2,000
1,000
900
800
V300LA2(P)
700
600
500
400
MAXIMUM PEAK VOLTS (V)
Figure 3
300
200
-3
10
V150LA1(P)
V130LA1(P)
-2
10
V130LA2(P) - V300LA4(P)
4,000
MAXIMUM CLAMPING VOLTAGE
3,000
MODEL SIZE 7mm
130 TO 300V
2,000
1,000
MAXIMUM PEAK VOLTS (V)
Figure 5
900
800
700
600
500
400
300
200
100
10
= -55oC TO 85oC
T
A
-3
-2
10
V320LA7(P) - V480LA7(P)
RATING
M(AC)
-1
10
PEAK AMPERES (A)
RATING
M(AC)
-1
10
10
PEAK AMPERES (A)
V275LA2(P)
10010
V300LA4(P)
V275LA4(P)
V250LA4(P)
V130LA2(P)
0
10110
V250LA2(P)
1
V230LA4(P)
V175LA2(P)
V150LA2(P)
V140LA2(P)
Repetitive Surge Capability for 7mm Parts
V130LA1(P) - V480LA7(P)
2,000
1,000
500
200
100
1
2
10
2
10
MODEL SIZE 7mm
V130LA1(P) - V480LA7(P)
3
10
4
10
5
10
6
10
50
20
10
SURGE CURRENT (A)
INDEFINITE
5
2
1
2
10
10
4
3
10
20 100 1,000 10,000
Figure 4
IMPULSE DURATION (μs)
LA Series
2
10
4
3
10
MAXIMUM CLAMPING VOLTAGE
5,000
MODEL SIZE 7mm
320 TO 480V
= -55oC TO 85oC
T
A
3,000
2,000
1,000
MAXIMUM PEAK VOLTS (V)
500
Figure 6
©2008 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/la.html for current information.
10-310-210-110010110
RATING
M(AC)
V460LA7
V480LA7
PEAK AMPERES (A)
(P)
(P)
V320LA7
V420LA7
V385LA7
2
(P)
10
(P)
(P)
3
10
4
115
Revision: January 9, 2009
LA Varistor Series
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