TISP7xxxF3 (MV, HV) Overvoltage Protector Series
APPLICATIONS INFORMATION
Lightning Surge (continued)
1.2/50 Generators (continued)
C4
8 nF
VC
1 kV
R2
13 Ω
C3
8 nF
SW
NOTE: SOME STANDARDS
REPLACE OUTPUT
CAPACITORS WITH
25 RESISTORS
Ω
R1
76 Ω
C1
1 µF
C2
30 nF
K.22 1.2/50 GENERATOR
Figure 34.
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.
Impulse Testing
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
protector.
Voltage
Peak Voltage
Peak Current
Current
Waveform
µs
TISP7xxxF3
25 °C Rating
A
Series
Resistance
Ω
Coordination
Resistance
Ω (Min.)
Standard
Setting
V
Va lue
A
Waveform
µs
2500
1000
1500
800
2/10
2 x 500
2 x 100
200
2/10
10/1000
10/160
10/560
5/320 †
5/320 †
4/250
2 x 190
2 x 45
110
50
GR-1089-CORE
12
NA
10/1000
10/160
10/560
9/720 †
(SINGLE)
(DUAL)
0.5/700
10/700
(SINGLE)
(SINGLE)
(DUAL)
6
8
100
FCC Part 68
(March 1998)
NA
1000
1500
1500
1500
1000
1500
4000
4000
25
70
70
2 x 95
70
37.5
2 x 27
37.5
25
37.5
100
0
I 31-24
0.2/310
5/310
5/310
5/310
4/250
0
0
0
17
0
NA
NA
NA
6
70
70
70
2 x 95
ITU-T K.20/K.21
2 x 72
6
† 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.
BOURNS [ BOURNS ELECTRONIC SOLUTIONS ]
