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NEW ERA UNIVERSITYCOLLEGE OF ENGINEERING AND TECHNOLOGY
ELECTRICAL ENGINEERING DEPARTMENT
EE 552D
ELECTRICAL MACHINE DESIGN
W: 10:00AM 1:00PM
DESIGN II B
DESIGN OF MAGNETIC CIRCUIT OF DISTRIBUTION TYPE TRANSFORMER
(FROM ITEM 24 TO ITEM 32)
NAME: Molina,Gillian S. RATING:
COURSE: BSEE DATE OF START: SEP 13,
DOS: SEP 22, 2010
ENGR. REYNALDO DELA CRUZ
INSTRUCTOR
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I. OBJECTIVES1. To have preliminary calculations of winding design of primary and secondary
item 1 up to item 23.
2. To determine the final data of the primary an secondary winding design.II. EQUIPMENT NEEDED
1-calculator
1-design book manual
1-laptop or computer
1-other reference book
III. PROCEDURESItem 1: Itis proposed to design a core type transformer with rectangular coils.
A subsequentdesign, Art. 147, will be devoted to the calculation of a cruciform-
coretype of
transformer.
Description . This is a distribution transformer of standard type for maximum
outputrating. Itis oil immersed and self cooling, withouttape for voltage
adjustment.
Insulation tests(in tank with oil) ; voltage applied for 1 min
H.T. winding to L.T. winding and core, 10,000 volts
L.T. winding to core, 4,000 volts
The specified temperature rise of 55rC means that the temperature of the
windings, as measured by the resistance method, after the transformer has been
operating continuously at full load, will not be more than 55rC above the
temperature of the surrounding air.
Item 33. By the formula the efficiencies at unity factor are :
At full load , 1-36.6 + 92..3
5 000 + 129.2= 0.9748
At half=load, 1-36.9 + 23.1
2 500 + 60 = 0.9766
The calculated values for other loads are:
At 25 percent overload, 0.9718
At full load, 0.9769
At full load, 0.9668
The maximum efficiency occurs when the total copper losses are equal to the
core loss, under which condition the fraction of rated load is.
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V. DATA AND RESULTItem
No.
Summary of Calculation
24.25.
26.
27.
28.
29.
30.
31.
32.
Dimension of window, in..Total flux, maxwells...
Flux density in core under windings, lines per
sq in..
Cross section of iron in core under windings,
in2
Width of stamping in core under windings, in.
Gross thickness of core, in
Watts loss in iron (compare with guarantee),lbs..
Total wt. of iron in core, lbs.
Total full load losses,
watts
16 1/4 x 5 1/21,000,000
85,000
41
4 1/2
619.84
268.22269.206
1036
Design Calculation
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Item No. 24: Dimension of Window, in
11 1/2 x 61/4
Item No. 25: Total Flux, maxwells
1,000,000 Maxwells
Item No. 26: Flux density in core under winding.
Bg = 85,000 Lines/in2
Item No. 27: Cross section of iron in core under winding.
= 0.9 (S x L) = 0.9x38.32x19.16
= 660 in.
Item No. 28: Width of stamping in core under windings.
L=4.5 or 4 in
Item No. 29: Gross thickness of core
S =38.32 in
Item No.30: Total wt. of iron in core
Wt of iron = 0.28(SFxSxM) x2 (H+M+S+L)
= 0.28(0.9 x 19.16 x 38.32) x2(5.145+10.16+38.32+38.32)
= 843.84 lbs.
Item No. 31: Wattss loss in iron (compare w/ guarantee)
Watts/lbs = 268.22 watts
Item No. 32 Total Full load losses, watts
= 268.22 + .986 = 269.206 watts
VI. GRAPH AND TABLE
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VII. REMARKS
VIII. CONCLUSIONTherefore I conclude that in this design of magnetic circuit it is very difficult
because of they have a less complex or variable. Thus also I conclude that the
emf voltage induced by the alternating flux in the primary and secondary coils will
be directly proportional to the number of turns in the perspective windings.
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