Example 32.10. A single-phase transformer has 500 turns on the primary and 40 turns on the secondary winding. The mean length of the magnetic path in the iron core is 150 cm and the joints are equivalent to an air-gap of 0.1 mm. When a p.d. of 3,000 V is applied to the primary, maximum flux density is 1.2 Wb/m². Calculate (a) the cross-sectional area of the core (b) no-load secondary voltage (c) the no-load current drawn by the primary (d) power factor on no-load. Given that AT/cm for a flux density of 1.2 Wb/m² in iron to be 5, the corresponding iron loss to be 2 watt/kg at 50 Hz and the density of iron as 7.8 gram/cm³.

Example 32.10. A single-phase transformer has 500 turns on the primary and 40 turns on the secondary winding. The mean length of the magnetic path in the iron core is 150 cm and the joints are equivalent to an air-gap of 0.1 mm. When a p.d. of 3,000 V is applied to the primary, maximum flux density is 1.2 Wb/m². Calculate (a) the cross-sectional area of the core (b) no-load secondary voltage (c) the no-load current drawn by the primary (d) power factor on no-load. Given that AT/cm for a flux density of 1.2 Wb/m² in iron to be 5, the corresponding iron loss to be 2 watt/kg at 50 Hz and the density of iron as 7.8 gram/cm³.

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 3.9P

See similar textbooks

Similar questions

Consider an ideal transformer with N1=3000andN2=1000 turns. Let winding 1 be connected to a source whose voltage is e1(t)=100(1| t |)volts for 1t1ande1(t)=0 for | t |1 second. A2- farad capacitor is connected across winding 2. Sketch e1(t),e2(t),i1(t),andi2(t) versus time t.
For a short-circuit test on a 2-winding transformer, with one winding shorted, can you apply the rated voltage on the other winding? (a) Yes (b) No
An ideal transformer has no real or reactive power loss. (a) True (b) False
For an ideal transformer, the efficiency is (a) 0 (b) 100 (c) 50
Match the following: (i) Hysteresis loss (a) Can be redud by constructing the core with laminated sheets of alloy steel (ii) Eddy current loss (b) Can be reduced by the use of special high grades of alloy stl as core material.
For an ideal 2-winding transformer, an impedance Z2 connected across winding 2 (secondary) is referred to winding 1 (primary) by multiplying Z2 by (a) The turns ratio (N1/N2) (b) The square of the turns ratio (N1/N2)2 (c) The cubed turns ratio (N1/N2)3
A single-phase transformer has 500 turns on the primary and 100 turns on the secondary. The mean length of the flux path in the core is 2.0 m and the joints are equivalent to an air-gap of 0.1 mm. The value of the magnetic field strength for 1.21 T in the core is 400 A/m, the corresponding core loss is 1.8 Watts/kg at 50 Hz and the density of the core is 7850 kg/m3. The cross-sectional area of the core is 0.0187 m2. If the maximum value of the flux density is to be 1.21 T when the nominal rated voltage is applied at 50Hz, calculate the magnitude of the primary current, in amperes, if a load current of 135 A is being supplied at a lagging power-factor of 0.85. Neglect the leakage impedances in the transformer windings.
The core of a transformer operating at 50 Hz has an eddy current loss of 100 W/m3 and the corelaminations have a thickness of 0.50 mm. The core is redesigned so as to operate with the same eddycurrent loss but at a different voltage and at a frequency of 250 Hz. Assuming that at the new voltage themaximum flux density is one-third of its original value and the resistivity of the core remains unaltered,determine the necessary new thickness of the laminations. Clear and detailed solution.
A single-phase transformer has 480 turns on the primary and 90 turns on the secondary. The mean length of the flux path in the core is 1.8 m and the joints are equivalent to an airgap of 0.1 mm. The value of the magnetic field strength for 1.1 T in the core is 400 A/m, the corresponding core loss is 1.7 W/kg at 50 Hz and the density of the core is 7800 kg/m3. If the maximum value of the flux density is to be 1.1 T when a p.d. of 2200 V at 50 Hz is applied to the primary, calculate: a. the cross-sectional area of the core; b. the secondary voltage on no load; c. the primary current and power factor on no load
. A 400/230V, 50Hz, single phase transformer has 200 turns on high voltage side. Find turns ratio, transformation ratio, and number of turns on low voltage winding. Also find the flux developed in the core
I need the answer quickly
A transformer has primary and secondary turns of 1250 and 125 respectively. It has core cross-sectionof 36 cm2 and its rms flux density is to be limited to 1.4 T (to prevent core saturation). Whatmaximum 50 Hz voltage can be applied on the primary side and the corresponding open-circuitsecondary voltage?The core has a mean length of 150 cm and its relative permeability can be assumed to be 8000. Whatwould be the rms exciting current when the transformer’s primary winding is excited at a voltage ascalculated above? Also calculate the magnetizing susceptance as seen from primary and secondarysides.If the transformer were to be excited at 60 Hz, 1. What should be the maximum primary voltage for thecore flux density limit not to be exceeded? 2. What would be the magnetizing susceptance as seen oneach side in this case?