RCDD CH9 POWER DISTRIBUTION EXAM QUESTIONS AND ANSWERS.

A Calculate the real power in watts needed to deliver 5 amperes of current in a 120 Volt ac circuit. The power factor for the circuit is 0.8. A - 480 W B - 600 W C - 750 W D - 900 W Page 9-13 B If the real power consumed by a load is 2000 W and the power factor is 0.8, how many tons of air conditioning is required to maintain ambient temperature in the space where the load is located? A - ≈ 0.3 tons B - ≈ 0.6 tons C - ≈ 0.75 tons D - ≈ 1 tons Page 9-13 A What type of fluctuation is caused by an increase in the nominal voltage or current lasting from 0.5 cycles to one minute? A - Swell B - Sag C - Overvoltage D - Transients/Surge Page 9-20 Table 9.3 A Which of the following is a method of connection for primary or secondary windings of a three-phase transformer bank in which similar ends of each phase winding are connected together at a common point, which forms the electrical neutral and is grounded (earthed) at the building grounding (earthing) electrode system? A - Wye B - Delta C - Split D - Monocyclic Page 9-3 A You are designing a system that requires an uninterruptible load transfer of small branch circuits. What type of transfer switch would be needed for this transfer requirement? A - Point of use switch B - Standalone transfer switch C - Integral isolation transformer and power PDU Page 9-54 D You have been asked to review specifications for the conductors and protection devices for a project. Upon calculating the information you notice that the feeder and branch circuits have been sized correctly to support the non continuous load plus: A - 25% of the continuous load B - 50% of the continuous load C - 100% of the continuous load D - 125% of the continuous load Page 9-23 D A facility runs a 3000 W load for 10 hours a day for a year. The utility company charges 5 cents per kWh. How much will the utility company charge the facility for electricity for the year? A - $150.00 B - $182.50 C - $300.00 D - $547.50 Page 9-12 C An allowable voltage drop of _____ over the total system, battery to load, is standard practice. A - 0.25 V B - 0.50 V C - 1.00 V D - 2.00 V Page 9-71 B If 540 W is measured on the load side and 600 VA is calculated on the line side of a circuit, what is the power factor? A 0.8 B 0.9 C 1.0 D 1.1 Page 9-12 A What type of fluctuation is caused by a decrease in the nominal voltage or current for more than 3600 cycles (one minute)? A - Undervoltage B - Sag C - Swell D - Interruption Page 9-20, Table 9.3 A Which of the following uninterruptible power supply (UPS) units power the load directly from the utility and only provide backup power when the utility power goes below preset tolerances? A Off-line B Line-interactive C Online double-conversion D Rotary Page 9-49 B You are tasked with supplying a design that has 50% nonlinear loads and 50% linear loads. What transformer K rating would you use? A K-4 B K-7 C K-13 D K-20 Page 9-25, Table 9.4