The primary resistance of a 440/110-V transformer is 0.5 Ω and the secondary resistance is 0.04 Ω. When 440 V is applied to the primary and secondary is left open-circuited, 200 W is drawn from the supply. Find the secondary current which will give maximum efficiency and calculate this efficiency for a load having unity power factor.

The primary resistance of a 440/110-V transformer is 0.5 Ω and the secondary resistance is 0.04 Ω. When 440 V is applied to the primary and secondary is left open-circuited, 200 W is drawn from the supply. Find the secondary current which will give maximum efficiency and calculate this efficiency for a load having unity power factor.

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

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.57P: A two-winding single-phase transformer rated 60kVA,240/1200V,60Hz, has an efficiency of 0.96 when...

See similar textbooks

Similar questions

(a) An ideal single-phase two-winding transformer with turns ratio at=N1/N2 is connected with a series impedance Z2 across winding 2. If one wants to replace Z2, with a series impedance Z1 across winding 1 and keep the terminal behavior of the two circuits to be identical, find Z1 in terms of Z2. (b) Would the above result be true if instead of a series impedance there is a shunt impedance? (c) Can one refer a ladder network on the secondary (2) side to the primary (1) side simply by multiplying every impedance byat2 ?
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.
For an ideal transformer, the efficiency is (a) 0 (b) 100 (c) 50
All values of a transformer are proportional to its __________________ ___________________.
The primary resistance of a 440/110-V transformer is 0.5 ohms and the secondary resistance is 0.04 ohms. When 440 V is applied to the primary and secondary is left open-circuited, 200 W is drawn from the supply. Find the secondary current which will give maximum efficiency and calculate this efficiency for a load having unity power factor.
A 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?
The open circuit and short circuit tests of a transformer show 200 W and 142 W respectively. The primary voltage is 380 V when it has a current of 25 A and power factor of 0,8. Find the full load efficiency and also the efficiency under 30% load conditions.
A 50 kVA transformer has an efficiency of 98% at full load,0.8 p.f. and 97% at half full-load, 0.8 p.f. Determine the full-load copper loss and iron loss. Find the load at which maximum efficiency occurs and also maximum efficiency.
In A circuit with an ideal transformer, Calculate:1. The currents I1 and I2.2. The power supplied to the 25 Ω resistor.3. The apparent power of the source.4. Simulation in Multisim.
Two 6600/250-V transformers have the following short-circuit characteristics: Applied voltage 200 V, current 30 A, power input 1,200 W for one of the transformers; the corresponding data for the other transformer being 120 V, 20 A, and 1,500 W. All value are measured on the H.V. side with the L.V. terminals short-circuited. Find the approximate current and the power factor of each transformer when working in parallel with each other on the high and low voltage sides and taking a total load of 150 kW at a p.f. of 0.8 lagging from the high voltage bus bars.
4.- 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)
Q3-A) The all-day efficiency of 250 KVA transformer is 96.5% when it is loaded follows 10 hours 9 hours 5 hours 150 k W at p.f. 0.8 lag 180k W at p. f. 0.9 lag no- load 3120 If maximum efficiency of this transformer occurs at 80% of full-load. Find iron loss and full-load copper loss finansformar according to their application