Manual line background information
Since the concept of EMC interferential critical value was introduced into the guidelines, refer to EN55011.022, many companies have started to self-attestation and production monitor and management. It means that more and more companies have noticed that by performing EMC(CISPR)accordance test standard can bring much potential benefit.
Every small change in inner development can be measured, tracked and corrected from the point of EMC accordance. By doing this, developing time and developing cost will be cut down.
Critical value of the current EMC standard regulation makes limit to interferential value intentionally or unconsciously. Before long, there will be EMC interferential finite standard on every kind of electric and electronic product-industrial standard, civilian standard and series production standard. The critical value of these electric and electronic products can be validated by test report made by independent laboratories provided by manufacturers or wholesalers, and also can be tested in test room that have suitable EMC test equipment, or use the both methods. The later method needs expensive test equipment cost, if use the whole set of equipment, so many companies will not take this method. The economical replaceable method is to use the basic equipment, so as to track and analyze the most important field at the developing stage, such as voltage radiation interference. In order to satisfy this requirement, equipment producers need a measure receiver or a spectral analysis machine and a manual line. This scheme can make the producers confirm the wireless interferential voltage value that the test equipment do to the main powernet.
Electric network broad band and measured without man-made line, the customers' quantities of main line, interference caused by short circuit and long-term interferential source will influence the power supply quality, and this influence is considerable that can be measured by EMC test.
If powernet loading high interference, CE accordance cannot be tested. Displayed by experience that before customers connect, the radiation value of main powernet will always exceed finite critical value.
Under this circumstance, we cannot get a reliable interferential voltage test value. In fact, different results will be gained. This is because of the different impedance level and other equipment and system linked to the main line determined. So, it's impossible to judge which aspect has made a progress. Compare with the diagram a) and b), the difference is obvious. Both are the results of true experiments.
Diagram a) main circuit test without manual line
Diagram b) main circuit test with manual line and advance colander
Set and function:
Manual line supplies tested substance with finite load impedance, meanwhile, makes a high frequency interval between tested substance and the main powernet that it connected to. For different purpose and current intensity, VDE0876 Part 1 present details about the impedance used. So this impedance is defined as manual impedance.
Diagram 1 is the sketch map of test process.
When designing manual line load impedance, (50 µH + 5 ohms) || 50ohms is used broadly. The data in the parenthesis is indicated in the form of partial impedance-the value of manual line. 50ohms that behind the paratactic marks means the input impedance of wireless interferential measure receiver. Because the manual impedance is decided according to certain standard, only this measure receiver can match the above impedance.
When carrying on a single-phase earth test, L line and N line connected to manual impedance respectively. It is similar to perform the test of four-phase connection. For different purpose, the mutual connected manual impedance value is different. For the main intention is to record anisomerous wireless interferential voltage. So-called V-network is used to produce manual main line network or the main line with the least inner impedance. All the manual impedance shares the same reference earth. Because the use of double pole forms, when connected, they form a V form. That's the origin of name of the main line.
In addition, there is fixed value manual impedance between some equipments and conductor. This is used to define symmetrical and anisomerous wireless interferential voltage. Communication system belongs to this type.
In order to avoid the mutual influence of manual impedance and affecting the main powernet, VDE0876 regulates that it should use high enough high frequency insulation. This point can be realized by the low transfer between the main line input and manual impedance.
The manual main line used at current practice:
- Only realized the function of manual main circuit described by manual main line load impedance standard and copy them simply are far from enough.
- Because the syntonic influence, autoecious inductance and autoecious will produce an unbearable error based on the descriptive load impedance.
- Similarly, in order to design high quality manual main circuit, there are high demands on the arranging order of each circuit units , the materials used and construction and quality of units.
- In the past years,Bajog provides high quality manual main circuit(single phase and 3-phase)that its current range is from 16A to800A for electrical system of cars,LISNs and special LISNs that flying in the sky or space.
- Bajog provides intelligent manual main line with operation interface for the purpose of various performance degree since may of 1997, to be selected by customers.
- Nowadays, it has became a crucial performance of automatic check and test order. In addition, Bajog provides LISN-cars electrical system, special purpose and communication system electrical system, installing according to ichnography and more for various industries mentioned above.
The advantage of this manual main line produced by Bajog is below:
- Low chroma and lighteness interference around the whole frequency (can estimate interferential voltage at any channel).
- Can be connected to finite high depressor
- The largest linear impedance windage is 2 ohm when voltage above 9kHz to 30MHz
- Modern and fashionable design
- Flexible, can be modified directly according to the requirements of customers.
Currently, Bajog provides 20 different kinds of changeable manual main line.Diagram2 is a typical frequency response curve.
In order to confine the interferential signal between manual main lines to 40dB at least, we should make a special design according to metrical value. Let's look at the diagram 3 showing the typical frequency response curve. Compare with diagram 3 and diagram 2, we can see obviously that one manual main line to the other chroma lighteness interferential suppression within 30MHz is far larger than the exception of 40 dB. Using this performance to go to interferential power supply is very useful. This precondition can make customers get an exact measurement when they use LISN and manual main line produced by Bajog. Moreover, we can make quality estimation on objects that are tested. In addition, LISN together with finite linked module can protect test receivers, and will make them free from switch high voltage and high voltage that caused by the failure of objects that are tested.
Conclusion:
Providing economical and reasonable test equipment technology to promote equipment and system manufactures, agencies and distributors discover and resolve EMC problem. In this way, they can keep the competitive superiority. In order to achieve this aim, Bajog always tries to produce high price contrast and high quality manual main line.
Benefit from the compensation unit of high power thyratron transistor controlled:
Electron produce; Not to influence by switch; Because of high current, the powernet is stable; Capacitors will not happen with high current load; Normal finite current technology is only fulfill through network impedance, the highest voltage is above 1600V; Not to produce over compensation and over voltage; No spark, can be used in volatile environment; No need to repair ( compare with normal technique);When turn on or turn off the power units, no noise will be produced(compare with normal technique); 32 degrees power factor can be adjusted a little cosf=1, avoiding of producing over voltage; Adjustment process can be changed (above 0 to 2000KVA, at 5ms - > 60 Sekunden eligible); Real-time compensation within a sine wave (Equalizer), completing within 15ms.