Electrical Power Systems Technology

330 Electrical Power Systems Technology Table 13-1. Conversion Chart for Electromagnetic Wavelengths ——————————————————————————— ...

Lighting Systems 331 on it per unit area. The unit of illumination is the lux (lumens per square meter) or footcandle (lumens pe ...

332 Electrical Power Systems Technology Incandescent lamps usual- ly have a thin tungsten filament, which is in the shape of a c ...

Lighting Systems 333 in Figure 13-4. The tube is filled with mercury vapor; thus, when an elec- trical current flows through the ...

334 Electrical Power Systems Technology heat produced by current flow through the heater. The filament circuit is now opened. A ...

Lighting Systems 335 lights can also be used for outdoor lighting. The sodium-vapor light, shown in Figure 13-7, is popular for ...

336 Electrical Power Systems Technology Another type of vapor lamp is called a metal halide type. This light source is a high in ...

Lighting Systems 337 energy. A measure of how well this is done is called efficacy. Efficacy is the lumens of light produced per ...

338 Electrical Power Systems Technology shown in Figure 13-10A, while Figure 13-11 presents a pictorial view of the same circuit ...

Lighting Systems 339 in order to provide the type of lighting control desired for each room. You should study the diagrams of Fi ...

340 Electrical Power Systems Technology Table 13-3. Building Lighting Requirements in Wattage per Square Foot —————————————————— ...

Lighting Systems 341 Figure 13-12. Circuit for controlling a light from three locations: (A) Schematic diagram, (B) Positions of ...

342 Electrical Power Systems Technology branch current units = ——————— load current 20 amperes = ————— 3 amperes = 6.67 units (r ...

Lighting Systems 343 Sample Problem: Given: a large room in an industrial building needs to have 40,000 watts of incandescent li ...

344 Electrical Power Systems Technology total bulbs required branch circuits = ————————————— number of bulbs per circuit 200 = — ...

Lighting Systems 345 the light absorption characteristics of walls, ceilings, and floors, when the coefficient of utilization of ...

346 Electrical Power Systems Technology Find: the total light output from the lighting system. Solution: Find the total light o ...

Lighting Systems 347 12,000 × 0.83 × 0.85 = ————————— 600 FC = 14.11 footcandles Considerations for Electrical Lighting Loads In ...

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Chapter 14 Mechanical Systems Another broad category of electrical loads includes those devices that convert electrical energy i ...