Modernization of Electrical engineering labs

1. BY
JABEZ WINSTON.C(11EE16)
3rd year EEE
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2.  Measuring
 Connecting
 Power supply
 Miscellaneous
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3. Why do engineering college labs use old MC
and MI instruments? Why not digital meters?
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5. First of all , you cannot be remain
outdated.Second thing is you measure only
voltage/current/power with those instruments
and hence there is no scope of learning lot from
them .Just for the sake of academic purpose , one
or two experiments can be done using such
instruments.We are in age where things are
shrinking.Hence there is no point in having bulky
instruments anymore.
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6. Less accuracy
Poor resolution
Can be easily damaged if mishandled
High cost
Large size
Internal impedance is low in case of voltmeter.
For example , a (0-30V) MC voltmeter’s internal
resistance is only 30kΩ which increases the
chance of loading effect.
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7. Highly accurate
High resolution
Low cost
Auto-ranging feature in some multimeters
Smaller size
High internal impedance(commonly
1MΩ,occasionally 10M Ω and sometimes even
40MΩ)
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9. Problems continued…
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10. Autorange multimeters
Pocket size DMM
Capable of measuring
frequency,capacitance,AC
current,etc.,
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11.  Clamp meter capable of
measuring current upto
1000 A
 Manual ranging
multimeter
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12. The way we connect measuring
equipments,auxillary equipments,device or
machine should change.
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13. The problem of many
instruments!!2 voltmeters,6
ammeters!!
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14. Typical Machines Lab Table
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15. A voltmeter( preferably digital) can be permanently
connected across
R and Y(Both supply and machine)
R and N(Both supply and machine)
A1 and A2
(+) and (-)
A ammeter can be connected with (+),R,A1,F1 terminals
The obvious reason is that it is frequently required to
measure armature voltage , field current , line voltage ,
phase voltage , supply voltage
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16. This would be better…
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17. Simplified circuit
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18. Time is saved
More complicated experiments can be carried out
Monotonous connecting work is minimized and hence
learning is enhanced
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19. Why not use 100V or 120V AC and 100V DC for
experimental purposes?
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20. Lower voltages are safer
The supply voltage in USA is 120V 60Hz
The power supply is Japan is 100V(50Hz is Eastern
Japan and 60Hz in Western Japan)
If phase voltage is 115V,then line voltage is just 200V
If supply voltages are lower,you can experiment more
with less risk
If supply voltages are higher,the only less
experimenting is possible
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21. How about working with smaller motors and
generators like this
Rated voltage: 115V
Rated current:2.5 A
Power: ½ HP…..
We could save the scarce power like this!!!Starting and stopping
the motor would be easy.
How about using power electronic
devices to control voltage, current
instead of old 3 point starter ,
autotransformer , rotor resistance
starter???
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