Скачать презентацию ELECTRICAL INSTALLATION PLANNING LSEGG 307 A 9080 F

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ELECTRICAL INSTALLATION PLANNING LSEGG 307 A 9080 F

Lesson Content • Describe the acceptable methods for determining the maximum demand on an installation’s consumer’s mains. • Calculate the maximum demand for the consumer's mains for given installations up to 400 A per phase.

Maximum Demand Non-Domestic Load are generally heavier Stay on for longer periods of time Heating & cooling has an effect on load

Residential Instillations • Hotels • Boarding Houses • Hospitals • Motels • etc AS/NZS 3000 Table C 2 Colum 2

Residential Instillations Lighting Load group A 75% connected load Note B Incandescent Lamps = 60 W Unless the fitting restricts the wattage to less Track lights = 0. 5 A/m AS/NZS 3000 Table C 2 Colum 2

Residential Installations 10 A Power Points Load group B If this section of building DOES NOT HAVE fixed heating/cooling Load Group Bi 20 Double power points 20 x 2 = 40 Points 1000 W + (39 x 400 W) = 16600 230 = First Point Balance 72. 2 A

Residential Installations 10 A Power Points Load group B If this section of building DOESHAS HAVE NOT fixed heating/cooling Load Group Biii 20 Double power points 20 x 2 = 40 Points 1000 W + (39 x 400 W) =16600 230 = 100 W) = 4900 230 First Point Balance 21. 3 A 72. 2 A

Residential Installations Power Points Larger than 10 A Load group Biii 1 st = full current of highest 2 nd = 50% x full current 3 rd = 50% x full current 2 x 20 A power points 2 x 15 A power points 20 A 0. 5 x 20 = 10 A 0. 5 x 15 A = 7. 5 A 45 A

Residential Installations Power Points 3 Outlets Load Group B 10 A 3 Outlet A 1 Point B 1 Point C 1 Point

Exercise 1 An air conditioned motel consists of the following: A A 30 x Light points ((30 x 60) 230)x 0. 75 = A B 40 x Lights ((40 x 60) 230)x 0. 75 = 5. 87 A 7. 83 A A C 6 x 400 W mercury vapour flood lights ((6 x 400) 230)x 0. 75 = 7. 83 A Bii A 15 x Double power points (p/p) 31 P (1000+(30 x 100)) 230 = 17. 4 A Bii B 10 x Single p/p & 15 x Double p/p 11+30 P (1000+(40 x 100)) 230 = 21. 7 A Biii C 3 x 15 A Single p/p (1000 230)+15+((2 x 15)x 0. 5) = 34. 3 A A Bii B 1 x 10 A 3 outlet C NSW S&IR Clause 1. 10. 3 23. 3 A 29. 5 A 42. 1 A Less than 25 A difference

Factories • Shops • Offices • Schools • Churches AS/NZS 3000 Table C 2 Colum 3

Factories Lighting Load group A 100% connected load Note B Incandescent Lamps = 60 W Unless the fitting restricts the wattage to less Track lights = 0. 5 A/m AS/NZS 3000 Table C 2 Colum 3

Factories AS/NZS 3000 2. 2. 2. 10 A Power Points Load group B If this section of building DOES NOT HAVE fixed heating/cooling Ø Ø Calculation Assessment Measurement Limitation Load Group Bi 20 Double power points 20 x 2 = 40 Points 1000 W + (39 x 750 W) = 30250 230 = First Point Balance 131. 5 A

Factories 10 A Power Points Load group B If this section of building DOESHAS HAVE NOT fixed heating/cooling Load Group Biii 20 Double power points 20 x 2 = 40 Points 1000 W + (39 x 750 W) = 30250 230 = 100 W) 4900 230 First Point Balance 131. 5 A 21. 3 A

Factories Power Points Larger than 10 A Load group Biii 1 st = full current of highest 2 nd = 75% x full current 3 rd = 75% x full current 2 x 20 A power points 2 x 15 A power points 20 A 0. 75 x 20 = 15 A 0. 75 x 15 A = 11. 25 A 57. 5 A

Welders AS/NZS 3000 C 2. 5. 2. 2 (b) 3 x 20 A 3 Welders Majority of welders only use 2 phases B A W 1 C W 2 Only 2 welders on each phase W 3 20 A + 20 A = 40 Amps Per Phase

C 3 Commercial & Light industrial Used to give a “Ball Park” figure of maximum demand when actual loads are not available in the initial design stages Values are given in VA per m 2 of floor area

C 3 Commercial & Light industrial 10 metre x 10 metre air conditioned shop 10 x 10 = 100 m 2 From C 3 Light & power (average value)= 70 VA/m 2 Air conditioning= 30 VA/m 2 100 m 2 x 100 VA/m 2 = 10 k. VA 400 x √ 3 = 14. 4 A /

Maximum Demand Final Sub-circuits • Single items on circuit Current rating of appliance • Multiple items on circuit Limit by circuit breaker • Diversity may be applied • Welders • Domestic cooking appliances

Welding Machines Types • Arc Welding Machines • Stick Highest 1 st Machine • MIG 2 nd • TIG 3 rd 4 th 5 th + more Lowest 100% 85% 70% 60% • Rated Primary Current • Actual Primary Current

Welding Machines Types • Arc Welding Machines • Stick • MIG • TIG • Resistance Welding Machines Spot welders • Rated Primary Current • Actual Primary current • Duty Cycle

Resistance Welding Machines • Individual Machines • Variable Operation • Seam welders 70% • Auto feed welders • Manual welders 50% • Non-Auto Welders x Rated Primary Current • Specific (fixed) Operation Actual Primary current x Multiplier

Duty Cycle Very few welders operate at 100% all of the time • Changing the electrodes • Repositioning the job • Starting a new job Ratio of ON TIME/OFF TIME in 1 minute Weld for 30 seconds Off for 30 seconds 30/30 = 50% Duty Cycle

Resistance Welding Machines • Individual Machines • Variable Operation • Seam welders 70% • Auto feed welders • Manual welders 50% • Non-Auto Welders x Rated Primary Current • Specific (fixed) Operation Actual Primary current x Multiplier • Groups of machines Highest 1 st Machine 100% 2 nd + More 60% Lowest

Domestic Cooking Appliances Table C 4 4. 8 k. W wall oven = 16 A 6. 8 k. W wall oven = 20 A 9 k. W wall oven + 4. 8 k. W hotplate = 13. 8 k. W = 40 A

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