Heater Catalog - Watlow

Strip/Clamp-On Heaters375 High-Temperature Strip HeatersApplications and Technical DataCalculating Watt DensityUse the Maximum Allowable Watt Density graphs andformulas to ensure the allowable watt density for theheater does not exceed the specific applicationrequirements. Watt density is calculated for one sideof the heater only.Part Temperature — °FPart Temperature — °F1200100080060040020012001000800600400200Watt Density =Heated Area(Offset Terminals) = [Overall Length (A) x 1.5 in.] - 6 in 2= [Overall Length (A) x 38 mm] - 38.7 cm 2Heated Area(Parallel Terminals) = [Overall Length (A) x 1.5 in.] - 4.7 in 2= [Overall Length (A) x 38 mm] - 30.3 cm 2600Heated AreaWatt Density — W/cm 22 4 6 8 10 12375 Strip < 24 in. (610 mm) O.A.L.; bar clampedoperating in 70°F (21°C) ambient air(One-on-One Terminals) = [Overall Length 500 (A) x 1.5 in.] - 6 in 2= [Overall Length (A) x 38 mm] - 38.7 cm 2375 Strip < 24 in. (610 mm) O.A.L.; bar clampedoperating in insulated or enclosedenvironmentsMaximum Allowable Watt Density ClampedUnits 24 in. (610 mm) and longerConsult Factory Watt Density — W/cm 22 4 6 8 10 12375 Strip < 24 in. (610 mm) O.A.L.; bar clampedoperating in 70°F (21°C) ambient air20 40 60 80 100375 Strip < 24 in.Watt Density — W/in 2 (610 mm) O.A.L.; bar clampedoperating in insulated or enclosedenvironmentsUnits 24 in. (610 mm) and longerConsult FactoryFormulasWattageHeated Area400300200100600500400300200100Part Temperature — °CPart Temperature — °C20 40 60 80 100Watt Density — W/in 2Sheath Temperature — °Fath Temperature — °F1200100080060040020012001000800600Maximum Allowable Watt Density in AirWatt Density — W/cm 22 4 6 8 10Sheath TemperatureWatt Density — W/cm(SS)22 4 6 8 10Sheath Temperature(Aluminized Steel)70°F (21°C) ambientoperating in still air20 40 Sheath 60 Temperature 80 100Watt Density —(Aluminized W/in 2 Steel)482 WATLOW ®400Sheath Temperature(SS)70°F (21°C) ambientoperating in still air600500400300200100600500400300200Sheath Temperature — °CSheath Temperature — °