Surge Protection Adaptors :
Astrolab,
Inc. Surge Protection Adaptors
are designed to prevent external high
energy transients from damaging sensitive
components and modules inside microwave
systems. These transients can be generated
by lightning strikes, switching on or
off high current inductive loads, electromagnetic
pulses or electrostatic discharge. The
waveforms induced by these transients
can last for several milliseconds and
reach kilovolts of potential and kiloamps
of current.
Typical
rise times are 1 to 10 µseconds with fall
times from 20 to 100,000 µseconds.
The
field replaceable plasma gas tube inside
the Surge Protector Adaptor limits the
intensity of the transient to a safe level.
The gas tube is a high speed switch that
turns on at a specified voltage and short
circuits the center conductor to the bulkhead.
The gas tube turns off after the transient
decays to a minimal level and allows the
RF signal to pass through the Adaptor
again. The Adaptor is typically bulkhead
mounted to the frame of the microwave
system with ground path for the transient
supplied by earthing the frame .
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Surge
Protector Characteristics
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Static
Breakdown Voltage:
|
145
volts (standard)
(other
voltages optional)
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Dynamic
Breakdown Voltage:
|
500
volts
|
Max.
Surge Current: (8/20 µs Pulse)
|
(10
strikes) 10 kA
(5
strikes) 20 kA
|
500
Amp Impulse Life: (10/1000 µs
Pulse)
|
1000
operations (min)
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Insulation
Resistance:
|
10
Gigaohms (min)
|
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Surge
Protector Typical Applications
|
Surge
Source:
|
Application:
|
Typical
Waveform
(Pulse)
|
Lightning
Strike
|
Communications
Lines
|
800V,
10/560 µs
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Antenna
Connected Equipment
|
1
kV, 8/20 µs
|
Modem
|
6
kV, 1/50 µs
|
Inductive
Switching
|
Cable
Extender
|
2.5
kV, 1.5/40 µs
|
Nuclear
Electromagnetic Pulse (NEMP)
|
The
gas tube inside the Surge Protector
requires a minimum input pulsewidth
of 1 µsec. to fire.
Use secondary protection (MOV,
etc.) for nanosec. pulses.
|
1
kV, 10/150 ns
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Electrostatic
Discharge (ESD)
|
5
kV, 10/100 ns
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