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The secondary winding of a real transformer has a terminal voltage of
The turns ratio of the transformer is
If the secondary current of the transformer is
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Chapter 2 Solutions
Earth Is the Lords
- A two-winding single-phase transformer rated 60kVA,240/1200V,60Hz, has an efficiency of 0.96 when operated at rated load, 0.8 power factor lagging. This transformer is to be utilized as a 1440/1200-V step-down autotransformer in a power distribution system. (a) Find the permissible kVA rating of the autotransformer if the winding currents and voltages are not to exceed the ratings as a two-winding transformer. Assume an ideal transformer. (b) Determine the efficiency of the autotransformer with the kVA loading of part (a) and 0.8 power factor leading.arrow_forwardElectrical engineering A 375 kVA, 6600/400 V, 3-phase core type transformer has a total loss of 3700 watts on full load. The transformer tank is 1.25 m in height and 1 m × 0.5 m in plan. Design a suitable scheme for cooling tubes if the average temperature rise is to be limited to 35 °C. The diameter of the tube is 50 mm and are spaced 75 mm from each other. The average height of the tube is 1.05 m.arrow_forwardA 2000 VA 440/110 V transformer has been tested to determine its equivalent circuit. The equivalent impedance referred to the LV side is 0.408/_75.4 deg ohm. If the full-load voltage is 110 V and the full-load current is lagging the voltage at an angle of 43.4 deg, what will the no-load voltage be?arrow_forward
- The maximum efficiency at Full-load and Unity power factor of a 1-phase, 25 kVA, 2000/1000V, 50Hz transformer is 98%. Determine its efficiency at 1/4th of full loadarrow_forward4.- A 20-kVA , 8000 V / 277 V transformer has the following resistances andreactance's:RP = 32Ω RS = 0.05ΩXP = 45Ω XS = 0.06ΩRC = 250 KΩ XM = 30 KΩThe excitation branch impedances are given referred to the high-voltage side of the transformer.a.- Find the equivalent circuit of this transformer referred to the high-voltage side.b.- Assume the transformer is supplying rated load at 277 V and 0.8 pf lagging. Whatis this transformer’s input voltage? (tip: assume the current through XM and RC is very small … negligible)arrow_forwardA 10 kVA, 500/250 V, single phase transformer has its maximum efficiency of 94% when delivering 90% of its rated output at unity p.t. Estimate its efficiency when delivering its full load output at p.t. of 0.8 lagging.3arrow_forward
- 9) A transformer primary voltage is 250 V and secondary voltage is 21 V, if the primary winding has 500 turns, determine the secondary turns, assuming an ideal transformer. a. 42 Turns b. 5952 Turns c. 10 Turns d. 21 Turnsarrow_forwardA 10 kVA three-phase transformer is loaded with a back power factor of 0.9, while the loading ratio is 50% and operates at maximum efficiency. The primary interphase voltage of this transformer is 10kV and it is delta connected. The equivalent circuit iron resistance reduced to the primary is 500 kiloOhms. What is the percent efficiency of the transformer when operating under the specified load? a) 88.24 b)78.95 c)85.71 d)83.33 e)92.31arrow_forwardThe primary and secondary windings of a 500 kVA transformer have resistances of 0.44 Ω and 0.0027 Ω, respectively. The rated primary and secondary voltages are 11013 V and 473 V, respectively and the core loss is 2.9 kW. Assuming the power-factor of the load to be 0.8, calculate the output at which the efficiency is a maximum. Give your answer in kVA correct to 2 decimal places.arrow_forward
- A 10 kVA, 500/250 V, single phase transformer has its maximum efficiency of 94% when delivering 90% of its rated output at unity p.t. Estimate its efficiency when delivering its full load output at p.t. of 0.8 lagging,arrow_forwardThe primary current to an ideal transformer rated at is 5 A.Calculate: (a) the turns ratio, (b) the kVA rating, (c) the secondary current.arrow_forward????????????:• Write the GIVEN with their respective symbols and units.• Do not skip the SOLUTIONS, do it step-by-step with their respective symbols and units???????:Calculate the all-day efficiency of a 100-KVA transformer operating under the following conditions:6 hour, 50 kW, 0.73 pf3 hours, 90 kW, 0.82 pfIron loss = 1000 wattsOne quarter load Copper loss = 66.25 wattsa) The rest of the day, transformer running idleb) The rest of the day, primary disconnected from the source.arrow_forward
Power System Analysis and Design (MindTap Course ...Electrical EngineeringISBN:9781305632134Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. SarmaPublisher:Cengage Learning