The LTF is equipped for conducting all the high voltage and
high current tests for the simulation of
lightning as per MIL, SAE and FAR (Federal Aviation Regulations) specifications. The main
constituents of the facility are:
Generator for High Voltage Tests
The Marx type impulse voltage generator has nominal ratings of 4000kV and 126 kJ. It can
generate the standard 1.2/50 Ás wave shape and other wave shapes as well.
Current Generators for
High Current Tests
On the basis of lightning zonal classification stipulated in the standards, each part of
the aircraft will have a different set of current waveforms to be applied for direct
effect testing. The current generators A,B, C, and D generate these waveforms and can be
operated either individually or in a sequence.
The generator A can deliver current pulse of 200 kA, duration less than 500 Ás and action
integral of , 2 x 10 6 A 2s through an inductive load of up to 6 ÁH
at a charging voltage of 60 kV.
The generator B can deliver near-rectangular current pulse of magnitude 2 kA (max voltage
5 kV),duration 5000 Ás, the charge transferred being 10 C.
The generator C can deliver rectangular current pulse of 200 A to 400 A (max voltage 1000
V) and adjustable duration up to 1s, so that charge transfer is 200 C.
The generator D can deliver current pulse of 100 kA, duration less than 500 Ás and action
integral 0.25 x 10 6 A 2s through an inductive load of 6 ÁH.
The above current pulses can be applied in the desired sequences and combination using an
output switch, which in turn comprises a set of adjustable spark gaps.
for Indirect Effect Testing
The Current generator E can
deliver a current of 50 kA with a rate of rise of current of about 35 kA/ Ás through an
inductance of about 6 ÁH,i.e., a full aircraft. The current is returned through a
mesh cage to achieve low inductance: The generator is used for assessing the lightning
induced EMI at the full aircraft level. This current is injected onto the
aircraft and E,H fields are measured inside the aircraft to identify the critical
locations;the performance of the LRU's and the systems can be monitored.
The test equipment for indirect effect testing at both LRU and systems levels are being
The LTF hangar is 48 m long, 30 m wide and 25 m high, and can
cater to full aircraft testing. A double-walled dark chamber measuring 8' x 8' x 8'
permits photography of any spark during current tests on small samples. A special
flameproof room for conducting fuel ignition test is also available.
measure the characteristics of the voltage and current generator outputs,suitable sensors
are incorporated and wherever necessary a fiber-optic system is used to couple the sensors
and measuring instruments, like digital oscilloscopes. The instrumentation is housed in an