Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series • • Impervious lead free vitreous enamel coating • Seven termination styles with choice of mounting arrangements • Manufactured RoHS compliant Pb-free terminations* Can be supplied with fixed, adjustable, tapped or low inductance winding * Check status of stock when ordering General Information Vitreous enamelled wirewound resistors are capable of withstanding a higher dissipation size for size, than any other protected type; this is attributable to the higher operating temperature which the wire and enamel can withstand. Vitreous enamel provides exceptionally good protection to the wire element and is essentially impervious to moisture. The resistors can safely be used in harsh environmental conditions. The Welwyn range is based on thirteen sizes of tube, each of which has a recommended maximum dissipation which limits operating surface temperature to a maximum of 375°C. The stability and high reliability of Welwyn tubular vitreous resistors is a direct result of the best quality materials being used in their construction. High purity ceramic tubes have been matched with nickel chromium resistance wires and specially formulated enamel to ensure that the resistors can withstand repeated heat cycling without damage. Connections between the resistance element and end terminations are welded; other connections are brazed. Mounting devices are available which permit resistors to be mounted by both ends or by one end. Single ended mounting is recommended for applications which do not subject the resistor to shock or vibration. Ferrules and the F type mounting plug are anchored into the tubes with high temperature adhesive. Special requirements, for types or styles not described in this brochure, will be considered for economic quantities. Electrical Data Power rating at 70°C Resistance range Limiting element voltage TCR (-55 to +200°C) Resistance tolerance Values Thermal impedance Operating temperature range watts ohms volts ppm/°C % Power rating at 70°C Resistance range Limiting element voltage TCR (-55 to +200°C) Resistance tolerance Values Thermal impedance Operating temperature range watts ohms volts ppm/°C % 1601 11 1905 16 1602 1906 1603 1604 17 22 25 35 See Table 1 See Table 1 Typically: <+75 Maximum + 200 1, 2, 5, 10 See table 1 for value restrictions E24 preferred See fig. 1 -55 to +375 °C/watt °C 1605 47 1600 16.5 1908 54 Typically: <+75 1, 2, 5, 10 °C/watt °C-55 to +375 1607 1606 76 91 See Table 1 See Table 1 1608 115 1609 165 Maximum + 150 See table 1 for value restrictions E24 preferred See fig. 1 Note See Figure 1 for curves of temperature rise / watts dissipation. General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. All information is subject to Welwyn’s own data, relates to current manufacture and is considered accurate at time of going to print. A subsidiary of TT electronics plc © Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com Issue E · 10.05 121 Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series Electrical Data (continued) Table 1 *Dissipation (watts) to produce operating hotspot temperature (°C) of: Ambient = 20°C Resistance range (ohms) Ambient = 70°C Limiting element voltage Minimum resistance at Termination style Low inductance winding resistance range (ohms) Min. res. at 200 300 375 375 ±5% ±2% ±1% Max. at any tolerance C All others ±10% ±5% Max. at either tolerance 5 10 14 11 1 15 25 15k 250 150 10 50 1.3k 1905 7 14.5 20 16 1 15 30 30k - 450 10 50 3.5k 1600 7.5 15 21 16.5 1 15 30 56k - 600 10 50 5.0k 1602 8 15.5 22 17 1 20 25 43k 500 350 10 50 4.0k 1906 9.5 19 28 22 1 20 30 50k 700 550 10 50 5.5k 1603 11 22 32 25 1 20 30 83k 850 750 10 50 7.5k 1604 15.5 31 45 35 1 20 60 100k 1300 1000 15 50 11.5k 1605 21 41 59 47 1 30 40 100k 1100 900 15 50 14k 1908 24 47 68 54 1 30 40 100k 1200 1000 10 50 16k 1607 34 66 95 76 1 30 50 100k 1300 900 15 50 22k 1606 41 80 115 91 1 30 40 160k 2100 1900 15 50 32k 1608 52 101 145 115 1 30 50 180k 2100 1800 20 50 38k 1609 74 145 208 165 1 35 50 250k 3000 2500 30 100 58k Type 1601 *The stated dissipation applies to resistors mounted horizontally with unobstructed bore. Performance Data Max Typ Load : 1000 hours at 70°C ∆R% 5.0 3.5 Shelf life : 12 months at room temperature ∆R% 1.0 0.1 Climatic ∆R% 0.5 0.35 Long term damp heat ∆R% 0.2 0.05 Bump and vibration ∆R% 0.1 0.02 Noise (in a decade of frequency) ∆R% zero Pulse Handling Data zero Available by request © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 122 Issue E · 10.05 Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series Physical Data Table 2 Dimensions in millimetres. See fig 2-8 for styles A B C D E F G H Type max max max nom max max nom ±.25 J K 1601 33.0 17.5 8.2 4.5 5.0 19.5 15 3.0 M3 59 1905 56.1 14.5 6.55 4.5 5.0 17.5 10 3.0 M3 - 1600 61.5 14.5 6.55 4.5 5.0 17.5 10 3.0 M3 - 1602 51.0 17.5 8.2 4.5 5.0 19.5 15 3.0 M3 77 1906 64.3 17.5 8.2 4.5 5.0 19.5 15 3.0 M3 90 1603 74.5 17.5 8.2 4.5 5.0 19.5 15 3.0 M3 101 1604 102 17.5 8.2 4.5 5.0 19.5 15 3.0 M3 128 1605 89.5 24.0 13.2 5.7 6.8 26.5 17 4.0 M4 122 1908 102 24.0 13.2 5.7 6.8 26.5 17 4.0 M4 134 1607 102 32.0 19.2 7.0 9.8 32.0 22 6.4 M6 134 1606 166 24.0 13.2 5.7 6.8 26.5 17 4.0 M4 198 1608 152 32.0 19.2 7.0 9.8 32.0 22 6.4 M6 184 1609 216 32.0 19.2 7.0 9.8 32.0 22 6.4 M6 248 max Terminations Styles B, 4B, AP and AW are available in all 13 tube sizes. Styles C, CB and CP are available in sizes 1601 to 1609 inclusive, 1906 and 1908 Ferrule, electrically isolated (Figure 6) Connection to resistor via Pb free solder coated nickle iron lugs. Denoted by prefix CB, thus: CB1602. Lugs (Figure 2): Pb free solder coated nickel iron. Denoted by prefix B to size reference, thus B1602 Ferrule, electrically live (Figure 7) Nickel plated brass. Denoted by prefix C, thus: C1602. Pigtails (Figure 3): 14/.193 mm copper, 150 mm minimum length. Denoted by prefix AP, thus AP1602 Ferrule, electrically isolated (Figure 8): Connection to resistor via pigtails of 14/.193 mm copper, 150mm minimum length. Denoted by prefix CP thus: CP1602 Rigid wires (Figure 4): 1.2 mm diameter tinned copper, 32 mm minimum length. Denoted by prefix AW, thus: AW1602 Lugs with screws, nuts and washers (Figure 5): Nickel plated brass screws and nuts. Denoted by prefix 4B, thus: 4B1602. Marking The resistors are legend marked with type reference, resistance value, tolerance and manufacturing date code. Value marking conforms to IEC 62. Solvent resistance: The vitreous coating and marking are resistant to all accepted industrial cleaning fluids. © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com Issue E · 10.05 123 Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series Adjustable Resistors (see Figure 9) Adjustable resistors use the same basic construction as fixed resistors already described, and have a window in the vitreous enamel through which contact is made to the resistive element by a sliding contact band. The band is fitted with a clamping screw and nut to retain it firmly in position. The adjustable winding style has a maximum permissible hot spot temperature of 300°C and the maximum dissipation, for an ambient temperature of 20°C, is specified in Table 4. The partial open winding necessitates a reduced maximum resistance, when compared with fixed resistors, and the resistance range is also defined in Table 4. More than one adjusting band can be fitted, up to the maximum number specified in Table 3. Adjustable resistors are available in termination styles B, 4B, AP, C, CB and CP, in sizes 1602 to 1609 inclusive and 1906 and 1908 denoted by prefix ‘V’. Table 3 Tube size A mm max. B mm max. Hole C dia. mm Max. no of adjusting bands 20 27 3.2 1 1605 20 27 3.2 3 1908 25 32 3.7 2 1606 25 32 3.7 4 1607 30 38 3.7 2 1608 30 38 3.7 3 1609 30 38 3.7 5 1602 1603 1906 1604 Table 4 Max. dissipation in 20°C ambient (watts) Type Resistance range (ohms) 200°C hot spot 300°C hot spot Min. for styles VC, VCP Min. for all other styles Max. for all styles 1602 8 15.5 4 3 1.6k 1906 9.5 19 4 3 2.5k 1603 11 22 6 6 3.0k 1604 16 31 8 8 5.3k 1605 21 41 6 6 4.5k 1908 24 47 11 10 7.5k 1607 34 66 11 9 8.1k 1606 41 80 14 13 13.2k 1608 52 101 17 16 15.4k 1609 74 145 25 24 25.5k Manufactured Values E24 preferred Standard Selection Tolerance ±10% All other details of the electrical and environmental performance of adjustable resistors are the same as for fixed resistors. © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 124 Issue E · 10.05 Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series Tapped Resistors See Figure 10 Ordering Procedure Fixed resistors can be supplied with taps to special order. Because of the reduced winding length, the total resistance of a tapped resistor will be less than can be offered on a fixed resistor of the same size. The reduction is proportional to the number of taps and Table 5 is intended as a guide. Enquiries for tapped resistors must state the following details: Resistance per section Maximum dissipation per section Maximum operating ambient temperature Maximum permissible dimensions if important The minimum resistance per section on all sizes is 1Ω and the standard selection tolerance for any section is ±10% Type of terminations required. (See ‘Terminations’, page 3) Resistor style or proposed method of mounting. Table 5 Maximum* resistance with single tap (ohms) Maximum* number of taps Type Maximum* total dissipation in 20°C ambient (watts) with single tap 1905 14.5 9k 1 1600 15.0 12k 1 1602 15.5 9k 1 1906 19.0 13k 1 1603 22 18k 1 1604 31 29k 2 1605 41 34k 2 1908 47 38k 2 1607 66 53k 2 1606 80 78k 4 1608 101 93k 4 1609 145 140k 4 Low Inductance Resistors Ayrton-Perry wound elements are supplied for low inductance applications. This winding style has a maximum permissible hot spot temperature of 300°C. The maximum dissipation is defined in Table 1 under the heading Operating hot spot temperature of 300°C, and resistance ranges are defined in the three right-hand columns of this table. Application Notes When cold, vitreous enamel has excellent insulation resistance. In common with all insulants the specific resistance of the enamel decreases with increased temperature; therefore, if operated at any temperature approaching the maximum, the resistor cannot be classed as an insulated type and should not be used in contact with any conducting materials. *Maximum total dissipation assumes that this will be evenly spread over the total element length. The recommended dissipations for each of the resistor hot spot temperatures applies to resistors mounted horizontally. If the bore is completely blocked a 15% derating is recommended. However, wherever possible, resistors should be mounted vertically with unobstructed bore. This makes best use of the chimney effect of the heated tube and will encourage a cooling stream of air through the bore. Allowances must be made, when tubular resistors are mounted in banks, for the effects produced by radiation between tubes. Appreciable reduction of hot spot temperature can be achieved by arranging that resistors are subjected to some measure of forced draught. In general, it is most efficient to extract air from the resistor enclosure and arrange that an air inlet is adjacent to the bottom of the tubes. If soft soldered connections are used the resistors should be derated where applicable to limit the hot spot temperature to 300°C. © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com Issue E · 10.05 123 Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series Table 6 mounting clip dimension (mm) See Fig. 11 Clip Type A B C D E F G ref. type nom. max nom. max max max ±0.2 1601 52 1602 70 86 MD1 1603 90 106 H dia J dia K nom Auxiliary locking spring ref 4.0 3.9 7.2 MD16 68 29 19 17.5 14.5 4.8 MD4 1604 121 137 1605 108 128 1906 83 99 Ordering Procedure 1607 125 146 MD3 1608 176 197 49 33 32.0 19.0 6.4 4.0 6.3 9.5 MD18 MD6 1609 240 261 Mounting clips (and auxiliary locking springs when required) should be ordered in units and the type reference specified. These mounting clips are suitable for termination styles C, CB and CP. MD4, 5 and 6 have an ear formed in the bottom surface of the bracket to prevent rotation of the mounting plate. The auxiliary locking springs ensure positive retention of the tube under severe mechanical shock conditions. See Figure 11. Table 7 Mounting brackets dimensions (mm). See Fig. 12. Bracket ref. Type A nom B nom C nom D nom E nom MD40 1600 78 92 10 20 4.2 1905 73 87 1601 50 64 1602 68 82 1603 91 105 13 20 4.2 1604 119 133 20 25 5.2 28 30 5.2 MD41 MD42 MD43 1906 81 95 1605 106 120 1606 183 197 1908 119 133 1607 121 143 1608 171 193 1609 235 257 Ordering Procedure Mounting brackets should be ordered in units and the type reference specified. These brackets are suitable for termination styles B, 4B, AP & AW Table 8 Mounting plug dimensions (mm) See Fig. 13. Type A B C Min. Max. 1.6 3.7 5.3 M4 1.6 3.7 5.3 M5 1601 1602 1603 1604 1906 1605 1606 1908 Ordering Procedure 1607 1608 3.2 5.2 6.8 1609 M6 Mounting plugs are denoted by the prefix ‘F’ added to the size reference; e.g. BF1602 and APF1602. F type bushes are suitable for termination styles B, 4B AP and AW © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 126 Issue E · 10.05 Tubular Vitreous Enamelled Wirewound Resistors Welwyn Components 1600/1900 Series Ordering Procedure Specify the full type reference, resistance value and tolerance, using IEC 62 code references. The addition of L to the prefix describing terminal configuration indicates Ayrton-Perry winding. Example: Electrically live ferrule terminated 1601 size at 10 ohms and 5% C 1601 - 10R J I Adjustable Option Fixed V Adjustable Termination Style B AP AW 4B CB C CP See Figures 2 to 8 Winding & Mounting Options Standard L Low Inductabce F Mounting plug Tube Size Value (USE IEC62 code) Tolerance (use IEC62 code) F 1% G 2% J 5% K 10% Packing I Box Standard Note - consult data sheet in detail for valid combinations. Minimium Ordering Quantity: 10 Order Multiple: 1 © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com Issue E · 10.05