Schwarzbeck NNBM 8124-200

Description

The main application of the unsymmetrical single path AMN (artificial mains network) NNBM 8124-200 is the measurement of interference voltage in vehicles, aircrafts and ships in the HF-VHF range 0.1 – 150 MHz. The NNBM 8124-200 can also be used for bulk current injection (BCI) testing or for transient measurements according to ISO 7637-2.

The impedance characteristic is realized according to CISPR 16 / 25 and MIL-STD-461F (5 µH + 1 Ω) || 50 Ω. With the optional external capacitor CAP 10-200 it can be used for DO-160 and DEF-STAN-59 as well. 

The continuous current rating is 200 A, for short time more than 280 A are possible. The EuT is connected to the wing terminals at the front panel. The mains terminals are on the backside

Interference voltage measurements acc. to CISPR 25 or MIL-STD-461F:

Mains has to be connected to the back side. The 1 µF capacitor must be switched on to filter external disturbance and to provide best isolation values. 

The DuT has to be connected to the front panel. The disturbance voltage is coupled to the BNC connector where it can be measured with an EMI receiver.

The switch at the front panel must be switched to “Measure”. In most cases one AMN for each line (e.g. + and -) must be used. In this case one NNBM 8124-200 must be connected to the “+” line with its red terminals and another one to the “-“ line, also to the red wing terminal.

The LISN of the line that is being measured has to be switched to “Measure”, the other one has to be terminated by switching the front panel switch to “50 Ohm termination”. The RFreference ground must be connected to the GND-terminals.

The 4 mm laboratory jacks at front- and back panel and the flat aluminium feet are electrically connected GND-terminals.

Immunity tests with bulk current injection (BCI-tests): 

The NNBM 8124-200 can be used for bulk current injection tests together with suitable current injection clamps. 

The maximum continuous power rating is 50 W at the EuT-terminals. With a continuous power input of 50 W the LISN housing heats up to approx. 60°C at the front panel. The operator must be aware of high temperatures.

A sufficient air-circulation must be provided to avoid overheating of the LISN. The LISN must not be covered by all means to provide good air ventilation. 

A light smell of coating and insulating material may appear in the first hours of operation. Ensure proper ventilation of the test rooms. The smell will reduce after few hours of operating. 

During bulk current injection tests danger may arise by high field strengths and temperatures (fire hazard!), therefore these tests must be carried out by qualified personnel only! The relevant safety precautions must be considered!  

For BCI-tests the switch position "50 Ohm Termination" is used. The power injected at the EuT-terminals is converted to heat inside the 50 Ω / 50 W resistors.