1 / 5

Calculate Max. Kilovolt-Amperes demand and nominal current required for the cable

Crane, pump and tools work for 25% of an 8 hour work day , 5 days a week for 48 weeks, 20 of the Tungsten lamps are used for security lighting 16 hours per night , and the remaining 40 tungsten lamps and discharge lamps are used 3 hours per day, 5 days per week during the 20 winter weeks.

Burraq
Download Presentation

Calculate Max. Kilovolt-Amperes demand and nominal current required for the cable

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Calculate Max. Kilovolt-Amperes demand and nominal current required for the cable A construction site and electrical equipment A construction site must have the following electrical equipment: •Tower crane, total of electric motors 75 kW at 415 V ; •Sump pump, 5 kW at 240 V ; •60 tungsten lamps of 100 W each at 240 V ; •12 spotlights of 400 W each at 240 V ; •20 hand tools of 400 W at 110 V . Calculate // 1.Find the kilovolt-amps to be supplied at the site if the power factor of all rotating equipment is 0.8 . 2.Find the electrical current rating for the incoming power cable at the site. 3.Estimate the cost of the electricity consumed on the site during a 12 month contract. Ok let's do it ... For rotating machines, the power formulas in Volt Amps [VA] are as follows:

  2. For single-phase current: For three-phase current: The results of the power calculations are given in Table 1 below. The answers required are as follows. 1. The total input power in kilovolts-amps required for the site is 120.8 kVA. 2. The capacity of the incoming power cable at 415 volts, three phase, 50 Hz required is as follows: This is the input current to the site at the voltage of this cable. This is not the same as the total currents calculated in Table 1, as these larger numbers appear only at their reduced voltages in the relevant subcircuits.

  3. 3. Suppose the crane, pump and tools work for 25% of an 8 hour work day , 5 days a week for 48 weeks, 20 of the Tungsten lamps are used for security lighting 16 hours per night , and the remaining 40 tungsten lamps and discharge lamps are used 3 hours per day, 5 days per week during the 20 winter weeks. The crane, pump and tools work for: Safety lights work for: The other lamps work for: Table 1 - Site installation schedule Equipment Power (kW) Number kW kVA V A Tower crane 75 1 75 93.75 415 130.4 Sump pump 5 1 5 6.25 240 26 Lamps 0.1 60 6 6 240 25 Flood lamps 0.4 12 4.8 4.8 240 20 Tools 0.4 20 8 10 110 90.9

  4. Total // 98.8 120.8 n / A. n / A. Table 2 - Construction site energy consumption Equipment Power (kW) Number Time (h) Energy (kWh) Tower crane 75 1 480 36000 Sump pump 5 1 480 2400 Tungsten lamps, safety lamps 0.1 20 5824 11648 Lamps 0.1 40 300 1200 Flood lamps 0.4 12 300 1440 Tools 0.4 20 480 3840 Total power used // 56528 The total energy used by the systems comes from: kWh = number of devices × kW per device × operating hours, as shown in table 2. If the electricity costs 8p per unit (kWh) then the estimated cost of the one-year contract will be:

  5. Burraq Engineering Solutions is providing practically electrical courses in Lahore. We offer PLC course, SOLAR SYSTEM Installation and DESIGN COURSE, ETAP course, DIALAX course, Panel FABRICATION course, VFD course, ADVANCED Course Panel, SWITCHERGEAR design course, Building Electrical design course and all electrical diploma courses in Lahore.

More Related