At just 2 mm thick the ultra low profile WDBR-UL power resistors from TT Electronics are of thick-film on steel construction. The specification for creep, air and power ratings conform to UL508 standards. Typical applications include frequency converters, dynamic braking, inrush current limiting, snubbers, heating elements in electronic assemblies and overvoltage protection for wind turbines.
The series offers nine resistance values (12, 15, 20, 22, 25, 47, 50, 100, 150 Ω) in five power ratings (170, 190, 240, 250 and 260 W). These figures correspond to continuous power when mounted on a heat sink with a thermal resistance of 0.53 ° C / W at 25 ° C. The load capacity increases to 660, 740, 850, 950 and 1,410 W respectively for forced ventilation at 5 m / s. The resistors can handle peak power up to 7 kW and single overload events up to 13 kW can be tolerated. They exhibit an inductance of <6 μH.
The resistors consist of a highly integrated dielectric layer deposited on a stainless steel substrate overprinted with the thick film resistive pattern. A final baking process encapsulates the resistor with a high-temperature glaze.
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Ultra low-profile power resistors
September 10, 2018 | 01:19
At just 2 mm thick the ultra low profile WDBR-UL power resistors from TT Electronics are of thick-film on steel construction. The specification for creep, air and power ratings conform to UL508 standards...