The Starbar TW element is a higher density element, used in severe applications such as corrosive atmospheres or where normal RR type elements do not provide acceptable service life. The TW element has a typical density 10 to 12% higher than normal RR elements. This higher density results in slower oxidation and aging, which yields longer element life. The dimensions and electrical properties of the TW element are similar to those of the RR element, therefore, a TW element may be interchanged directly for an RR element. The TW element due to its higher density may be more prone to thermal shock during installation into hot furnaces. Special care should be used not to thermal shock new elements during installation and heat up.
TW Starbars are described by giving the overall length, the heating section length, and the diameter. As an example, TW 43 x 24 x 1 is a Starbar 43" overall with a 24" hot zone, and 1" in diameter.
All Resistance values are +/- 20%.
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|Item #||Nominal Diameter||Hot Zone (Electrical Resistance)||Cold End (Electrical Resistance)|
|TW-5/8-16||5/8 inch 16 mm||0.12450 Ohms/Inch 0.00490 Ohms/mm||0.00631 Ohms/Inch 0.000248 Ohms/mm|
|TW-3/4-19||3/4 Inch 19 mm||0.08790 Ohms/Inch 0.00346 Ohms/mm||0.00433 Ohms/Inch 0.00017 Ohms/mm|
|TW-1-25||1/1 Inch 25 mm||0.05100 Ohms/Inch 0.00200 Ohms/mm||0.0025 Ohms/Inch 0.000098 Ohms/mm|
|TW-1/-1/4-32||1-1/4 Inch 32 mm||0.03200 Ohms/Inch 0.00126 Ohms/mm||0.00171 Ohms/Inch 0.000067 Ohms/mm|
|TW-1-1/2-38||1-1/2 Inch 38 mm||0.02120 Ohms/Inch 0.00083 Ohms/mm||0.00117 Ohms/Inch 0.000046 Ohms/mm|
|TW-1-3/4-44||1-3/4 Inch 44 mm||0.01650 Ohms/Inch 0.00065 Ohms/mm||0.00082 Ohms/Inch 0.000032 Ohms/mm|
|TW-2-1/8-54||2-1/8 Inch 54 mm||0.01490 Ohms/Inch 0.00059 Ohms/mm||0.00075 Ohms/Inch 0.00003 Ohms/mm|