Determine the efficiency of 1500kVA, 2300V, 3phase, Y-connected alternator, which operates at rated output with a power factor of 80%. The DC armature resistance at 70°C between terminals is 0.08Ω. The field takes 70A at a 120V from the exciter equipment. Friction and windage loss are 15kW, iron loss is 35kW and stray load losses is 1.5kW. Assume the effective armature winding resistance is 1.5 times the DC value.

Determine the efficiency of 1500kVA, 2300V, 3phase, Y-connected alternator, which operates at rated output with a power factor of 80%. The DC armature resistance at 70°C between terminals is 0.08Ω. The field takes 70A at a 120V from the exciter equipment. Friction and windage loss are 15kW, iron loss is 35kW and stray load losses is 1.5kW. Assume the effective armature winding resistance is 1.5 times the DC value.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter2: Fundamentals

Section: Chapter Questions

Problem 2.21P: An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor...

See similar textbooks

Similar questions

A 25 MVA turbo-alternator is working on full load at a power factor of 0.8 and efficiency of97%. Find the quantity of cooling air required per minute at full load, assuming that 90% ofthe total losses are dissipated by the internally circulating air. The inlet air temperature is20° C and the temperature rise is 30° C. Given that specific heat of air is 0.24 and that 1 kg ofair occupies 0.8 m3.
Determine the efficiency of a 1500kVA, 2300 V, 3 phase, Y-connected alternator, which operatesat rated output with a power factor of 80%. The DC armature resistance at 70°C betweenterminals is 0.08 ohm. The field takes 70 A at 120 V from the exciter equipment. Friction andwindage losses are 15kW, iron loss is 35kW and stray load losses is 1.5kW. Assume the effectivearmature winding resistance is 1.5 times the DC value.
A 25 MVA turbo-alternator is working on full load at a power factor of 0·8 and efficiency of 97%. Find the quantity of cooling air required per minute at full load, assuming that 90% of the total losses are dissipated by the internally circulating air. The inlet air temperature is 20o C and the temperature rise is 33 30o C. Given that specific heat of air is 0·24 and that 1 kg of air occupies 0·8 m .
Two similar 6600 V, 3-phase alternators are running in parallel sharing equally a total load of 10,000 kW at a lagging power factor of 0.8, the two machines being similarly excited. If the excitation of one machine is adjusted so that its armature current is 438 A, find the armature current and power factor of the second machine if the steam supply is not changed. [Ans. cos Ꝋ2 = 0.568 (lag)]
A 3-phase, star -connected turbo-alternator, having a synchronous reactance of 10 Ω per phase and negligible armatureresistance, has an armature current of 220 A at unity p.f. The supply voltageis constant at 11 kV at constant frequency. If the steam admission is unchangedand the e.m.f. raised by 25%, determine the current and power factor.
National Power Corporation has A 3-phase, Wye -connected turbo-alternator, having a synchronous reactance of 10 Ω per phase and negligible armature resistance, has an armature current of 220 A at unity p.f. The supply voltage is constant at 11 kV at constant frequency. If the steam admission is unchanged and the e.m.f. raised by 25%, determine the current and power factor. [288.6 A , 0.762 (lag)]
A single-phase alternator connected to 6,600-V bus-bars has a synchronous impedance of 10Ω and a resistance of 1 Ω. If its excitation is such that on open circuit the p.d. would be 5000 V, calculate the maximum load the machine can supply to the external circuit before dropping out of step and the corresponding armature current and p.f. [2864 kW, 787 A, 0.551]
Determine the efficiency of a 1,500 kVA, 2500V, 3 phase, Y-connected alternator which operates at rated output with a power factor of 80%. The dc armature resistance between terminals is 0.80 ohm. The field takes 70 A at 120 V from the exciter equipment. Friction and windage losses are 15 kW, iron loss is 35 kW and stray load losses are 1.5 kW. Assume the effective armature winding resistance is 1.2 times the DC value.
A 100KVA, 3000V, 60Hz, 3-phase, wye connected alternator operates at rated KVA at a power factor of 86.6%. The de armature winding resistance between terminals is 1.24Ω. The field current of 40A produces a short circuit current of 200A and and open circuit emf of 1040V. What will be the open circuit voltage circuit voltage across two terminals (in Volts) at 0.866 pf leading if the effective armature winding resistance is 1.15 of the dc resistance.
Determine the efficiency of a 1500kVA, 2300 V, 3 –phase, Y – connected alternator which operates at rated output with a power factor of 80%. The DC armature resistance at 70º C between terminals is 0.08 ohm. The field takes 70 A at 120 V from the exciter equipment. Friction and windage losses are 15kW, iron loss is 35kW and stray load losses is 15 kW. Assume the effective armature winding resistance is 1.5 times the DC value. a. 94.56 % b. 90.31 % b. 93.35 % d. 92.62 %
A 500-V, 50-kVA, single-phase alternator has an effective resistance of 0.2 Ω. A field current of 10A produces an armature current of 200A on short-circuit and emf of 450V on open circuit. Calculate (a) the synchronous impedance and reactance and (b) the full-load regulation with 0.8 p.f. lagging.
Calculate for full-load and unity p.f., the natural period of oscillation of a 50-Hz, 10,000-kVA, 11-kV alternator driven at 1500 r.p.m. and connected to an infinite bus-bar. The steady short-circuit current is four times the full-load current and the moment of inertia of the rotating mass is 17,000 kg-m2. ANSWER IS [1.148 second]