|TISP7150F3D||MEDIUM & HIGH-VOLTAGE TRIPLE ELEMENT BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS|
|TISP7150F3D Datasheet PDF : 19 Pages |
TISP7xxxF3 (MV, HV) Overvoltage Protector Series
Lightning Surge (continued)
1.2/50 Generators (continued)
NOTE: SOME STANDARDS
25 Ω RESISTORS
K.22 1.2/50 GENERATOR
There are 8/20 short circuit current defined generators. These are usually very high current, 10 kA or more and are used for testing a.c.
protectors, primary protection modules and some Gas Discharge Tubes.
To verify the withstand capability and safety of the equipment, standards require that the equipment is tested with various impulse wave forms.
The table in this section shows some common test values.
Manufacturers are being increasingly required to design in protection coordination. This means that each protector is operated at its design
level and currents are diverted through the appropriate protector, e.g. the primary level current through the primary protector and lower levels
of current may be diverted through the secondary or inherent equipment protection. Without coordination, primary level currents could pass
through the equipment only designed to pass secondary level currents. To ensure coordination happens with fixed voltage protectors, some
resistance is normally used between the primary and secondary protection (R1a and R1b, Figure 36). The values given in this data sheet apply
to a 400 V (d.c. sparkover) gas discharge tube primary protector and the appropriate test voltage when the equipment is tested with a primary
25 °C Rating
2 x 500
2 x 190
2 x 100
2 x 45
FCC Part 68
2 x 27
2 x 95
2 x 72
2 x 95
† FCC Part 68 terminology for the waveforms produced by the ITU-T recommendation K.21 10/700 impulse generator
NA = Not Applicable, primary protection removed or not specified.
If the impulse generator current exceeds the protector’s current rating, then a series resistance can be used to reduce the current to the
protector’s rated value to prevent possible failure. The required value of series resistance for a given waveform is given by the following
calculations. First, the minimum total circuit impedance is found by dividing the impulse generator’s peak voltage by the protector’s rated
current. The impulse generator’s fictive impedance (generator’s peak voltage divided by peak short circuit current) is then subtracted from the
minimum total circuit impedance to give the required value of series resistance. In some cases, the equipment will require verification over a
temperature range. By using the derated waveform values from the thermal information section, the appropriate series resistor value can be
calculated for ambient temperatures in the range of 0 °C to 70 °C.
MARCH 1994 - REVISED MARCH 2006
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
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