EC&M’s Electrical Calculations Handbook - Chapter 13 doc

... operation: Figure 1 3-3 : Air-conditioning equipment Figure 1 3-4 : Household appliances Figure 1 3-5 : Heat tracing with self-regulating cable (see Note below) Figure 1 3-6 : Heat tracing with constant-wattage ... tracing with constant-wattage cable Figure 1 3-7 : Lighting fixtures Figure 1 3-8 : Electrical power receptacles with unidenti- fied loads Figure 1 3-9 : Electrica...

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... coil. 272 260 Figure 9-1 0 Table replicating part of NEC Table 45 0-3 (a), overcurrent protec- tion of transformers over 600 V. 274 Figure 9-1 2 Table replicating part of NEC Table 45 0-3 (b), overcurrent protec- tion ... form, showing that in a wye-con- nected system the phase-to-phase voltage is equal to the coil voltage multiplied by the square root of 3. Three-phase wye Figure...

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... continuous load 1 3-1 Conductor size for general load 1 3-8 Conductor size for general receptacle load 1 3-4 Conductor size for household appliance 1 3-3 Conductor size for HVAC load 1 3-5 Conductor ... surface reflectances 8-2 Common lamps and their characteristics 1 3-7 Conductor size for commercial lighting load 1 3-6 Conductor size for constant-wattage heat tracing cable...

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... Volt, 3-phase 4-wire wye Note 5 460 Volt, 3-phase 3-wire delta Note 4 600/347 Volt, 3-phase, 4-wire wye 2400 Volt, 3-phase, 3-wire delta 2400 Coltm 3-phase, 4-wire wye 4160/2400 Volt, 3-phase, 4-wire ... -j 104 = (180) 2 + (104) 2 Minus Phase b voltage - (120 120 ° = - 120 -6 0 ° ) = -( -1 20 COS 60 -j 120 SIN 60) = -[ (-1 20)(5) -j (120)(.866)] = -[ -6 0 +j 103.92]...

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... capacitance. 82 72 Chapter Three Figure 3-1 (Continued) -J 45 ° 60 ° +J NEW RESULTANT VECTOR 180 - 37.4° AMP 20.9 -1 6.6 +j 12.7 (-X, +J) (+X, +J) (-X, -J) (+X, -J) Step 3. Draw the resultant vector. +X +J -J (-X, ... vector. +X +J -J (-X, -J) NEW RESULTANT VECTOR -1 6.6 +j 12.7 180 ° - 37.4 ° AMP 20.9 (-X, +J) (+X, -J) 142.6 ° (+X, +J) 37.4 ° Step 4. Determine the ang...

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... 90 2 1-2 5 7 0-7 7 1.08 1.05 1.04 2 6-3 0 7 8-8 6 1 1 1 3 1-3 5 8 7-9 5 0.91 0.94 0.96 3 6-4 0 9 6-1 04 0.82 0.88 0.91 4 1-4 5 10 5-1 13 0.71 0.82 0.87 4 6-5 0 11 4-1 22 0.58 0.75 0.82 5 1-5 5 12 3-1 31 0.41 0.67 0.76 5 6-6 0 ... REMARKS 31 0-1 6 OR 31 0-1 7 31 0-1 6 OR 31 0-1 7 UNDERGROUND FEEDER CABLE 31 0-1 6 OR 31 0-1 7 MOISTURE AND HEAT RESISTA...

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... 13. 8-kV bus. Fault power is available to flow into this bus from 1. The electrical utility source 2. The 24-megawatt (MW), 30-MVA generator 3. The 5000-hp motor 4. The 200-hp motor 5. The 40-hp ... electrical systems against damage during short-circuit conditions is required by the National Electrical Code (Secs. 11 0-9 and 11 0-1 0). Short-Circuit Calculations 181 For example,...

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... power conductors and generator overcurrent pro- 200 Chapter Six Gas-turbine generators arrive at the installation site prepackaged on skids. Figure 6-2 Solve for generator overcurrent protection ... the watt load, and the elec- trical dynamo must be sized to allow selected motors to start while other selected electrical loads are in operation. Except in very unusual electrical system...

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... such as a 460-volt (V), three-phase, three-wire delta system, an arc- ing fault that repeatedly restrikes can cause voltage “jack- ing” of up to six times the normal system phase-to-neutral voltage. ... enough equipment-grounding conductors, as shown in Fig. 7-4 . Since system grounding is done at the service-disconnect- ing means, the equipment-grounding conductor and the neu- tral (“groun...

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... necessary to use the point-by-point method. The Point-by-Point Method How to make point-by-point calculations Later in this chapter, lighting calculations within areas hav- ing reflective surfaces, ... footcandles from the second luminaire. Sample point-by-point lighting calculations Refer to Fig. 8-1 for sample point-by-point lighting calcula- tions for both the nadir point and a po...

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