Comwave Institute of sarhad University. uncertainty calculation in sum, product, quotient, difference, power . Electromechanical Instruments

1. Instrumentation and Measurements by David A Bell
Presented By: Engr. FAZAL UR REHMAN
Lecturer Electrical KPTEVTA
Visiting Lecturer COMWAVE INSTITUTE ISLAMABAD

2. Today's Topics
“ELECTROMECHANICAL INSTRUMENTS”
a) Some important Topics From past papers
b) Permanent Magnet Moving Coil Instrument
c) Galvanometer
d) DC Ammeter

3. Some Exam Topics From

13. Permanent Magnet Moving Coil
Instrument
 Current Flow in the coil is responsible for Deflecting
Force which move pointer from zero.
 Spiral spring at the pivot of pointer provides
Controlling Force which brings back the pointer to 0.
 Eddy current in the core of coil provide damping
force which dampen the oscillations of pointer.

21. Galvanometer

24. DC Ammeter

26. Shunt Resistance

27.  Numerical Example

31. Ayrton Shunt

32. Any Question???