Siemens has developed a thermography-based analysis system for the diagnosis ...

Thermal images are recorded in order to investigate both defects and functioning parts of a module. These are then compared with corresponding images in a reference database. If sources of faults are identified, the test system automatically outputs recommendations for repairs and spare parts. This reduces the time required to diagnose and repair frequency converter modules by up to 30 percent. That, in turn, not only reduces the expenditure on repairs and spare parts, but also enables realistic estimates to be made of the remaining service life and risk of the module failing. Electronic modules are subject to diverse loads during operation that can lead to power losses. These loads frequently cause the temperature of the components and their surroundings to rise, and this can be made visible by thermography. A thermal imaging camera is used to capture the temperature distribution on the surface. This method requires only a few minutes to check electronic modules for thermal risks, damage and critical areas. The analysis quickly provides reliable information about the current operating condition, long before damage would otherwise become visible. The Siemens automatic module analysis system also uses this methodology. It involves dismounting the control unit, and subjecting it to an electrical functional test. The temperature distribution over the surface is then determined by measuring the infrared radiation. A thermal image is taken immediately after the module is switched on in order to detect any faults arising during the ramp-up sequence. This is followed by further functional tests, for each of which new images are taken. The recordings are then compared with reference images in a database. The sources of the faults thus identified are immediately output as a report, which includes a recommended repair, and specifies the spare parts required. The exact repair required for the defective component can then begin. The Siemens thermography-based fault analysis system is used by the repair service for frequency converters and, if required, can also be adapted for use on other types of modules. It contributes toward reducing the time required to diagnose and repair frequency converter modules, and lowers the expenditure on repairs and spare parts. It takes less time than conventional methods of analysis which do not use thermography, and also has a hit rate up to ten percent higher. That reduces the failure rate of the components and increases their reliability. As well as for identifying the repair required, the test system can also be used to examine the quality characteristics of modules. For example, complete batches can be tested, and the resulting report given to the ordering party. The results are input into further development of the modules concerned.

Behlman Modified High-power Frequency Converter Improves Testing ...

Hauppauge, New York (PRWEB) April 25, 2007

Behlman Electronics Inc., known for its leadership in providing power products for aviation, industrial, commercial and military applications, has received customer acceptance for the modified Behlman BL+120 EWFR three-phase frequency converter.

The equipment to be tested by the BL+120 is on certain commercial aircraft. It has the ability to take the electrical power created over a wide range of variable aircraft engine speeds and convert it to a fixed 400 Hz, to power a variety of equipment on the aircraft. To test the proper operation of this airborne equipment during manufacture, installation and maintenance, a frequency converter had to be developed that would work across a 350 HZ to 2000 Hz Extreme-Wild-Frequency-Range (EWFR).

Modifying a standard Behlman frequency converter met this need.

With a standard BL+120 already supplying most of what was needed, Behlman engineers were able to modify the unit to provide a number of specialized test functions and parameters, including Crowbar-shutdown, Current limit shutdown, Phase-angle adjustment, Fault alarms and Pulse-by-Pulse testing at an EWFR of 350 HZ to 2000 Hz.. The Final Acceptance Test (FAT) was witnessed and accepted by the customer at Behlman’s facilities in March 2007 and product shipped one week later. The number of units ordered by this customer is confidential.

Ron Storm, Behlman’s Vice President of Marketing and Sales had this to say. “It is particularly gratifying to see how readily Behlman is able to modify its standard product to serve the highly specialized needs of virtually any industry. This engineering capability enables us to raise the performance bar without the high cost of developing all-new products, which shortens development time and greatly reduces client costs.”

The BL+120 is a low-cost, three-phase, solid state frequency converter with a small footprint that delivers clean, regulated high-power AC and has proven to be ultra-reliable for industrial product testing, precision avionic test, power conversion, ATE, bulk power and motor generator replacement.

The BL+120 incorporates a 36-pulse multi-phase input rectification that provides for low input current harmonics IAW MIL STD 1399 Section 300A. Input startup surges are reduced through the use of special soft start circuitry, and isolation is provided by the input transformer. Output voltage of 0-132 VAC or 0-264 VAC, L-N are standard. Optional output transformers are available for other voltages. The standard output frequency for unmodified units can be fixed at 50 Hz, 60 Hz or 400 Hz, or variable from 45 to 500 Hz. (The output frequency of the new EWFR model BL+120 is variable from 350 Hz to 2000 Hz.) The BL + Series is available from 25 KVA to 120 KVA.

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