Type SR & SXR Smoothwound Resistors-75 to 1050 Watts Type SR Smoothwound Resistor APPLICATION Type SR Smoothwound Resistor Powerohm's Type SR & SXR Smoothwound Resistors can be used in any AC or DC power circuit. Units are most commonly used for light-duty braking of variable frequency drives, small horsepower motor control, space heaters and any low wattage, high resistance load application. The Type SR & SXR resistors are suitable for continuous duty applications where high resistance and low current are required. These units are designed to withstand consider- able shock, making them suitable for high vibration applica- tions. ELECTRICAL CHARACTERISTICS BASIC CONSTRUCTION VOLTAGE INSULATION: A standard Type SR and SXR High-quality components are used to manufacture resistor is insulated for up to 600 volts maximum. End Powerohm's Type SR and SXR resistors assuring long life insulation can be added to increase this to 1000 volts. and reliability. Our smoothwound resistors are durable units Standard enclosures can be insulated for voltages exceed- consisting of a low temperature coefficient resistance wire ing 1000 volts. wound on a high-quality steatite tube. After fixed termina- tions are installed, the units are coated with a ceramic RESISTANCE TOLERANCE: + 10% for all units; + 3% if cement. The SR resistor has a special coating which required. contains a coarse sand. This special granular coating increases the surface area of the unit, yielding a much higher COEFFICIENT OF RESISTIVITY: Resistance values will watt density per size than can be obtained using vitreous increase as the element temperature rises. Expect an enamel or ordinary resistor cement. approximate increase of 5% in resistance after the unit reaches an operating temperature of 375ºC above ambient. Our ceramic insulating cores are manufactured in-house to Contact the factory for more specific information if needed. maintain total control over production and quality standards. Powerohm is the only domestic resistor manufacturer with AMBIENT TEMPERATURE: Standard ratings are based on this added advantage. maximum ambient temperatures of 40ºC. Derate wattage rating 90% for 50ºC ambient, 80% for 80ºC ambient and 70% for 100ºC ambient. OPTIONS EFFECTS OF ALTITUDE: The published electrical ratings COIL SIZES: Type SR & SXR resistors are available in (13) are applicable for altitudes of 6000 feet or less. Contact the standard sizes. Wattage values vary from 75 to 1050 watts factory for deration factors above 6000 feet. per coil. These units are custom wound to any resistance value required within the limits of the resistance range listed in the table on the following page. CUSTOM DESIGNS Powerohm offers a complete selection of standard size TERMINALS: Multiple fixed, or adjustable terminals which coils. Each size coil has the same wattage rating and can slide along the element to any position on the coil, are be furnished with almost any desired resistance value. available for all units. Numerous variations are available for almost any applica- tion. Please contact the factory if there are special service ENCLOSURES: Powerohm Type SR & SXR Smoothwound requirements, such as overloads, high peak currents, high Resistors can be mounted on brackets or in our standard ambient temperatures, etc. selection of enclosures. See the enclosure section of our catalog for details, or contact the factory for assistance. 5713 13th Street Katy, Texas 77493 POWEROHM Phone: (281) 391-6800, Fax: (281) 391-6810 Ω Please visit our website at www.powerohm.com RESISTORS, INC. Type SR & SXR Electrical Ratings & Coil Dimensions SPECIFY PART NUMBERS AS FOLLOWS: SR or SXR ___ -___ -___. For example, the part number for a 200 watt, 100 ohm coil is SR5-100. The Size catalog number for the same coil with an Resistance Required adjustable terminal is SR5-100-A. Add an "A" for an adjustable terminal. RATINGS: The continuous current ratings are based on a 375ºC temperature rise. The resistance values are measured at 25ºC and have a + 10% tolerance. TYPE SR ELECTRICAL RATINGS & DIMENSIONS OF STANDARD SIZE COILS DIMENSIONS IN INCHES RESISTANCE SIZE WATTAGE RANGE (OHMS) A B C D E 1/2 3 75 2 - 1500 3 1-1/4 13/64 3/4 1/2 4 125 2 - 2500 4 1-1/4 13/64 3/4 1/2 5 200 3 - 5000 5-1/2 1-1/4 13/64 3/4 1/2 6 250 3 - 5000 6-1/2 1-1/4 13/64 3/4 1/2 7 300 3 - 5000 7-1/2 1-1/4 13/64 3/4 1/2 8 350 3 - 5000 8-1/2 1-1/4 13/64 3/4 1/2 10 450 4 - 7500 10-1/2 1-1/4 13/64 3/4 TYPE SXR ELECTRICAL RATINGS & DIMENSIONS OF STANDARD SIZE COILS DIMENSIONS IN INCHES RESISTANCE WATTAGE SIZE RANGE (OHMS) A B C D E 3/4 2 300 2 - 1500 6 2 7/32 1-1/8 3/4 3 450 2 - 2000 9 2 7/32 1-1/8 3/4 4 600 3 - 2500 12 2 7/32 1-1/8 3/4 5 750 4 - 3000 15 2 7/32 1-1/8 3/4 6 900 4 - 3500 18 2 7/32 1-1/8 3/4 7 1050 5 - 4000 21 2 7/32 1-1/8 FRONT VIEW SIDE VIEW C E B D A 24 HOUR EMERGENCY SERVICE (800) 838-4694