MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC...
Transcript of MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC...
![Page 1: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/1.jpg)
MAGNETIC MEASUREMENTS
• The measurement of different magnetic phenomena is known as magnetic measurements
• The magnetic phenomena to be measured are – Flux
– Flux density
– Magnetising force
– Perrmeability
– B-H Curve
33
![Page 2: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/2.jpg)
TYPES OF TESTS
• Study of magnetic measurements are classified as:
– DC tests or ballistic tests
– AC tests – done at high frequencies
– Steady state tests – to measure air gap flux
34
![Page 3: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/3.jpg)
DC OR BALLISTICS TESTS
• For determining
– Flux/ flux density of a magnetic specimen
– B-H Curves
– Plotting Hysteresis loop
35
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 4: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/4.jpg)
MEASUREMENT OF FLUX/FLUX DENSITY
36
![Page 5: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/5.jpg)
MEASUREMENT OF FLUX/FLUX DENSITY
• Ring specimen is wound with a coil
• Coil carries current I
• Coil is connected in series with resistance R and calibrating coil to BG – Ballistic Galvanometer
• Current through the coil is reversed so that an emf is developed in the coil
• That emf is measured by BG
37
![Page 6: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/6.jpg)
MEASUREMENT OF FLUX/FLUX DENSITY
38
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 7: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/7.jpg)
MEASUREMENT OF FLUX/FLUX DENSITY
• Θ – throw of galvanometer
• Gq- galvanometer constant
39
![Page 8: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/8.jpg)
MEASUREMENT OF MAGNETISING
FORCE (H)
40
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 9: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/9.jpg)
MEASUREMENT OF MAGNETISING FORCE (H)
41
![Page 10: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/10.jpg)
MEASUREMENT OF MAGNETISING FORCE (H)
• Magnetizing force can be determined by measuring H on the surface of material
• It is due to tangential forces on the surface are equal in magnitude on both sides
• Coil is position to measure flux density B
• If permeability is known then H can be found
42
![Page 11: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/11.jpg)
Determination of B-H Curve
• Two methods:
– Method of reversals
– Step by step method
43
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 12: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/12.jpg)
Determination of B-H Curve by METHOD OF REVERSALS
44
![Page 13: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/13.jpg)
Determination of B-H Curve by METHOD OF REVERSALS
Construction
• Ring shaped specimen is used
• Thin tape is put on ring
• Coil is insulated by paraffined wax and is uniformly wound over the tape
45
![Page 14: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/14.jpg)
Determination of B-H Curve by METHOD OF REVERSALS
Working
• Specimen is demagnetised
• Magnetising current I is set to small vlue
• BG switch K is closed and switch S is operated 20 times backward and forward – to bring the specimen to reproducible magnetic state
• Key K is opened
• Value of flux corresponding to reproducible magnetic state ie H is taken
46
![Page 15: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/15.jpg)
Determination of B-H Curve by METHOD OF REVERSALS
Working
• Value of B can be formulated by knowing relative permeability and value of H
• Flux is the ration of B (flux density) to area ofspecimen
• The above steps are repeated by various values of H upto maximum testing point
• B-H Curve is plotted from values of B and H
47
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 16: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/16.jpg)
Determination of B-H Curve by STEP BY STEP METHOD
48
![Page 17: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/17.jpg)
Determination of B-H Curve by STEP BY STEP METHOD
• No reversal of magnetizing current
• Current is given to the coil by a potential divider having number of tappings
• By varying the position of tapping, current I can be varied so H can be increased upto desired maximum value
49
![Page 18: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/18.jpg)
Determination of B-H Curve by STEP BY STEP METHOD
Working
• Initially switch S1 is open
• Tapping is put at position 1
• Key K is open
• Switch S1 is closed
• Deflection in the galvanometer is noted – B(flux density)
• Current I is also noted
50
![Page 19: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/19.jpg)
Determination of B-H Curve by STEP BY STEP METHOD
Working
• Procedure is repeated in taping 2, 3, etc…
• Value of B and current is noted
• 𝐻 =𝑁𝐼
𝑙
• By knowing value of current I, H is found
• From the above values B-H Curve is plotted
51
![Page 20: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/20.jpg)
Determination of B-H Curve by STEP BY STEP METHOD
52
![Page 21: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/21.jpg)
COMPARISON OF BAR AND RING SPECIMENS
Ring specimen Bar specimen
Ballistic tests gives high accuracy Ballistic tetss gives less accuracy
End effects are absent End effects are present
Free from errors due to magnetic leakage Errors are there due to magnetic leakage
Uniform winding should be there Uniform winding is easy
Magnetic flux density is not same at inner and outer portions
Uniform magnetic flux density all over the specimen
60
![Page 22: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/22.jpg)
PERMEAMETERS
• Permeameters are instruments used to plot B-H
curves of straight magnetic specimens
• It gives true value of H in the relation
𝐵 = μ𝐻
• It generally consists of steel frame to which bar
type magnetic specimen is connected
61
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 23: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/23.jpg)
PERMEAMETERS
Perm
eam
eter
s Hopkinson
permeameter
Ewing double bar permeameter
Illovici Permeameter
Burrow’s permeameter
Fahy’s Simplex Permeameter
National physical laboratory (England) form Permeamter
62
![Page 24: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/24.jpg)
Hopkinson’s Permeameter (Bar and Yoke Method)
63
![Page 25: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/25.jpg)
Hopkinson’s Permeameter (Bar and Yoke Method)
• Test coil is wound on central part of specimen
• Bar is clamped between two halves of massive iron yoke
64
![Page 26: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/26.jpg)
Hopkinson’s Permeameter (Bar and Yoke Method)
65
![Page 27: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/27.jpg)
Hopkinson’s Permeameter (Bar and Yoke Method)
66
![Page 28: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/28.jpg)
Hopkinson’s Permeameter (Bar and Yoke Method)
67
![Page 29: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/29.jpg)
Hopkinson’s Permeameter (Bar and Yoke Method)
• Flux density B is measured by Ballistic Galvanometer
68
![Page 30: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/30.jpg)
EWING DOUBLE BAR PERMEAMETER
69
![Page 31: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/31.jpg)
EWING DOUBLE BAR PERMEAMETER
• Two similar bar specimens under test
• Two pairs of magnetisng coils, one pair exactly half length of other, axial length is same
• Bar specimens are fixed into two yokes
• Position of yokes on the bars can be adjusted
• Tests are done at length l and l/2
70
![Page 32: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/32.jpg)
EWING DOUBLE BAR PERMEAMETER
71
![Page 33: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/33.jpg)
EWING DOUBLE BAR PERMEAMETER
72
![Page 34: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/34.jpg)
EWING DOUBLE BAR PERMEAMETER
73
![Page 35: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/35.jpg)
EWING DOUBLE BAR PERMEAMETER
• Flux density B is measured by ballistic galvanometer
• B-H curves are plotted for full and half lenghts
74
Edited with the trial version of Foxit Advanced PDF Editor
To remove this notice, visit:www.foxitsoftware.com/shopping
![Page 36: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/36.jpg)
BURROW’S PERMEAMETER
80
![Page 37: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/37.jpg)
BURROW’S PERMEAMETER
• S1- bar specimen to be tested
• S2- similar specimen
• M1,M2- magnetising windings
• A1,A2, B2,B2- compensating windings for elimination of leakage at joints
• C, C’- similar search coils
• D1, D2 – search coils having half number of turns of C, C’
81
![Page 38: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/38.jpg)
BURROW’S PERMEAMETER
82
![Page 39: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/39.jpg)
BURROW’S PERMEAMETER Working
83
![Page 40: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/40.jpg)
BURROW’S PERMEAMETER
84
![Page 41: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/41.jpg)
FLUXMETERS
• A special type of ballistic galvanometer
– Very small control torque
– High electromagnetic damping
• Grassot fluxmeter
92
![Page 42: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/42.jpg)
FLUXMETERS Grassot flux meter
93
![Page 43: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/43.jpg)
FLUXMETERS Grassot flux meter
Construction
• Small cross section carrying coil C
• Cross section is suspended in narrow air gap of permanent magnet
• Current is injected to the coil through annealed silver springs
94
![Page 44: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/44.jpg)
FLUXMETERS Grassot flux meter
Construction
• Pointer is fixed to moving system
• Scale of pointer is calibrated in terms of flux turns
• Flux meter is designed by Grassot
95
![Page 45: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/45.jpg)
FLUXMETERS Grassot flux meter
• Spirals of silver spring makes controlling torque minimum
• Since controlling torque is minimum, pointer takes some time to come back to zero position
• Readings are obtained by taking by the deflection between initial and final positions of pointer
96
![Page 46: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/46.jpg)
FLUXMETERS Grassot flux meter
• Resistance of coil is minimum
• Inductance of coil is large
97
![Page 47: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/47.jpg)
FLUXMETERS Grassot flux meter
• Let ϕ1 − 𝑖𝑛𝑡𝑒𝑟𝑙𝑖𝑛𝑘𝑖𝑛𝑔 𝑓𝑙𝑢𝑥 𝑖𝑛 𝑖𝑛𝑖𝑡𝑖𝑎𝑙
position
ϕ2 − 𝑖𝑛𝑡𝑒𝑟𝑙𝑖𝑛𝑘𝑖𝑛𝑔 𝑓𝑙𝑢𝑥 𝑖𝑛 𝑓𝑖𝑛𝑎𝑙
position
98
![Page 48: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/48.jpg)
FLUXMETERS Grassot flux meter
• Let Ɵ1 − 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑑𝑒𝑓𝑙𝑒𝑐𝑡𝑖𝑜𝑛
Ɵ2 − 𝑓𝑖𝑛𝑎𝑙 𝑑𝑒𝑓𝑙𝑒𝑐𝑡𝑖𝑜𝑛
99
![Page 49: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/49.jpg)
FLUXMETERS Grassot flux meter
100
![Page 50: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/50.jpg)
FLUXMETERS Grassot flux meter
Advantages
• Deflection is same irrespective of change in flux
• Portable
101
![Page 51: MAGNETIC MEASUREMENTStijubaby.weebly.com/uploads/4/3/6/9/4369784/module_4_part1.pdf · MAGNETIC MEASUREMENTS •The measurement of different magnetic phenomena is known as magnetic](https://reader036.fdocuments.in/reader036/viewer/2022071504/6124f9932bbcc449b419cdde/html5/thumbnails/51.jpg)
Differences
102