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Varistor Products

High Energy Industrial Thermally Protected

* Figure 4: Typical time to open circuit under UL1449

Abnormal Overvoltage Limited Current Test

0.1

1

10

10

100

1000

10000

Time s

0.125A

0.5A

2.5A

5A

Typical

For applications exceeding 85ºC ambient

temperature, the peak surge current and energy

ratings must be reduced as shown in Figure 3.

Figure 5: Peak Current & Energy Derating Curve

0

20

40

60

80

100

-55

50

60

70

80

90

100

110

120

130

AMBIENT TEMPERATURE (ºC)

Thermal Characteristics

Note : The Industrial TMOV Series TMOV34S devices are intended, in

conjunction with appropriate enclosure design, to help facilitate TVSS

module compliance to UL 1449, Section 37.4 (abnormal over-voltage lim-

ited current requirements). Under these extreme abnormal over-voltage

conditions, the units will exhibit substantial heating and potential venting

prior to opening. Modules should be designed to contain this possibility.

Application testing is strongly recommended.

Pulse Rating Curves

FIGURE 6. SURGE CURRENT RATING CURVES FOR

HB34, HF34 and HG34

Hx34

50,000

20,000

10,000

5,000

2,000

1,000

500

200

100

50

20

10

20

100

1,000

10,000

IMPULSE DURATION (µs)

10

1

INDEFINITE

2