Type VR Ventwound Resistors - 2.5 to 16.7 Amps APPLICATION Type VR Ventwound Resistor Powerohm's Type VR Ventwound Resistors can be used for any AC or DC power application. Units are most commonly used for braking of variable frequency drives, motor control, load banks and neutral grounding applications. The Type VR resistors are suitable for continuous duty applications where low current and relatively high resistance are required. These units are designed to withstand continu- ous current ratings between 2.5 and 16.7 amps, and resistance values ranging between 170.0 and 1.0 ohms, respectively. Units have a rated temperature rise of 375ºC above ambient temperature, which is in accordance with NEMA standards. ELECTRICAL CHARACTERISTICS BASIC CONSTRUCTION VOLTAGE INSULATION: A standard Type VR resistor is insulated for 1000 volts. Our standard bracket and enclo- Powerohm's Type VR resistors are lightweight, durable sure assemblies are also insulated for 1000 volts. Also, with units consisting of a high quality stainless steel alloy wound special precautions and additional insulation, units can be around a toothed ceramic insulator. The element is attached used for applications exceeding 15 kV. at either end of the core by stainless steel terminals, or at various points for multiple connections. All resistors are RESISTANCE TOLERANCE: + 10% for all units; as low as supported by a threaded rod passing through the center of + 3% if required. the ceramic core. These units include a ceramic insulator, fixed terminals, through rods, hardware and stainless steel COEFFICIENT OF RESISTIVITY: Resistance values will element. increase as the element temperature rises. Expect an approximate increase of 5% in resistance after the unit The Type VR resistor is an open-type design, which allows reaches an operating temperature of 375°C above ambient. the element to come into direct contact with ambient air. Contact the factory for more specific information if needed. This unique design allows for rapid, efficient cooling of the resistor element. AMBIENT TEMPERATURE: Standard ratings are based on maximum ambient temperatures of 40°C. Derate current Our ceramic insulating cores are manufactured in-house to rating 95% for 50°C ambient, 90% for 75°C ambient, and maintain total control over production and quality standards. 85% for 100°C ambient. Powerohm is the only domestic resistor manufacturer with this added advantage. EFFECTS OF ALTITUDE: The published electrical ratings are applicable for altitudes of 6000 feet or less. Contact the OPTIONS factory for deration factors above 6000 feet. COIL SIZES: Type VR resistors are available in (6) standard lengths, all having the same approximate 2 inch diameter. CUSTOM DESIGNS Wattage values vary from 250 to 1100 watts per coil. These units are available in (17) different current ratings. Powerohm offers a complete selection of standard size coils on the following page. These coils cover a wide range of ADJUSTABLE TERMINALS: Adjustable terminals, which resistance and current values. Numerous variations are can be clamped to the element, are available for all units; add available for special applications or replacement of other "-A" to the part number. manufacturers. Powerohm can match the electrical ratings of any ventwound style product available. Please contact ENCLOSURES: Powerohm Type VR resistors can be the factory for assistance. packaged in our wide selection of enclosures. See the Enclosure Section of our catalog for details. 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 VR Electrical Ratings of Standard Size Coils SPECIFY PART NUMBERS AS FOLLOWS: VR __ - __ . For example, the part number of a 9.4 amp, 8.7 ohm coil is VR5-9.4. Length Amp Rating RATINGS: The continuous current ratings are based on a 375°C temperature rise. The resistance values are measured at 25°C and have a + 10% tolerance. ELECTRICAL RATINGS OF STANDARD SIZE COILS RESISTANCE IN OHMS CONTINUOUS AMP RATING LENGTH 2 LENGTH 3 LENGTH 4 LENGTH 5 LENGTH 6 LENGTH 7 16.7 1.0 1.6 2.2 2.7 3.3 3.9 14.9 1.2 2.0 2.7 3.4 4.2 4.9 13.3 1.6 2.5 3.4 4.3 5.3 6.2 11.9 2.0 3.1 4.3 5.5 6.7 7.9 10.6 2.5 4.0 5.5 7.0 8.5 9.9 9.4 3.1 5.0 6.9 8.7 10.6 12.5 8.4 3.9 6.3 8.6 11.0 13.3 15.7 7.3 5.0 8.0 11.1 14.1 17.1 20.1 6.5 6.4 10.2 14.0 17.8 21.6 25.5 5.9 7.9 12.6 17.3 22.0 26.7 31.4 5.2 9.9 15.9 21.9 27.8 34.0 40.0 4.5 13.3 21.2 29.2 37.0 45.0 53.0 4.1 16.7 26.7 37.0 47.0 57.0 67.0 3.6 21.2 34.0 47.0 60.0 72.0 85.0 3.2 26.6 42.0 59.0 75.0 90.0 107.0 2.8 34.0 54.0 74.0 94.0 114.0 135.0 2.5 43.0 68.0 93.0 120.0 144.0 170.0 Type VR Coil Dimensions & Tap Options TYPE VR VENTWOUND DIMENSIONS COIL DIMENSIONS: The coil dimensions are for standard size STANDARD COIL DIMENSIONS units. Coil and threaded rod length can be varied per customer request. All units have the same approximate diameter of 2 LENGTH A B C inches. Units are furnished with 5/16" through rods and #10 terminal hardware. 7 6-1/8 2 9-3/8 FRONT VIEW SIDE VIEW 10 9-1/8 3 12-3/8 1/4 DIA. 13 12-1/8 4 15-3/8 2-3/4 16 15-1/8 5 18-3/8 19 18-1/8 6 21-3/8 C B 21 20-1/8 A 7 24-3/8 ADDITIONAL TAPS Type VR resistors are furnished with two stainless steel terminals at either end of the ceramic core. Additional fixed taps, welded in place at various intervals, are available for coils rated 7.3 amps and higher. Numerous tap configura- tions are available, but limited to a spacing no closer than 1 inch. SPECIFY PART NUMBERS AS FOLLOWS: - For example, the part number of a 9.4 amp, 8.7 ohm coil with 2 taps at 1/3 Part Number spacing is VR5-9.4-2C. See below for additional part number examples. Number of Taps Spacing (See Table) Other part number examples of Type VR ADDITIONAL TAPS & SPACING CHART Ventwound Resistors with additional taps. FRACTIONAL SUFFIX SPACING LETTER 1/2 B 1/3 C 1/4 D 1/5 E 1/6 F VR3-16.7-1B 1/7 G (1 TAP @ 1/2 SPACING) 1/8 H 1/9 J 1/10 K 1/11 L 1/12 M 1/13 N 1/14 P 1/15 R VR3-16.7-2C 1/16 S (2 TAP @ 1/3 SPACING) 1/17 T 1/18 V 1/19 W 1/20 X 1/21 Z Type VR Mounting Bracket Options & Dimensions Type VR Ventwound Resistors are available fully assembled on open-style brackets. This open-style construction consists of resistors installed on mill galvanized brackets complete with all stainless steel bus bars. SPECIFY PART NUMBERS AS FOLLOWS: - . For example, the part number of a 9.4 amp, 8.7 ohm coil mounted on B1 Brackets is 1VR5-9.4-B1. Number of Coils in Assembly Bracket assemblies consisting of 2 or more coils include series jumpers. Add "-N" to eliminate Part Number jumpers and "-P" for parallel jumpers. Bracket Identification STANDARD BRACKET DIMENSIONS DIMENSION SIZE 2 SIZE 3 SIZE 4 SIZE 5 SIZE 6 SIZE 7 A 9 12 15 18 21 24 B 8 11 14 17 20 23 B1 BRACKET ASSEMBLY OPTIONS & DIMENSIONS FRONT VIEW SIDE VIEW #10 HARDWARE 3-1/2 7/16 DIA. B 2 A B2 BRACKET ASSEMBLY OPTIONS & DIMENSIONS FRONT VIEW SIDE VIEW #10 HARDWARE 6 7/16 DIA. B 3-1/4 A B3 BRACKET ASSEMBLY OPTIONS & DIMENSIONS FRONT VIEW SIDE VIEW #10 HARDWARE 9 7/16 DIA. 3-1/4 B A 24 HOUR EMERGENCY SERVICE (800) 838-4694 P0000 0.00 0000W P0000 0.00 0000W P11026 1.23 1500W