What is the limitation of Electrodynamometer type wattmeter?
Answers
Disadvantages. (i) They have a low torque/weight ratio and hence have a low sensitivity. (ii) Low torque/weight ratio gives increased frictional losses. (iii) They are more expensive than either the PMMC or the moving iron type instruments.
Errors Caused by Mutual Inductance Effect: In between pressure and current coil, the mutual inductance produces an error. Eddy Current Error: It creates own magnetic field in the coil, which effects the main current flowing through the coil. Stray Magnetic Field Error: The main magnetic field is disturbed due to this.
What are the advantages of electrodynamometer?
As the instrument coils are air cared, so these instruments are free from hysteresis and eddy current errors.
These instruments can be used on both a.c. and d.c. and since they have a precision grade accuracy, they are very useful as transfer instruments.
Electrical Engineering ⇒ Topic : Advantages and Disadvantages of Dynamometer Type
These types of instruments can be used for both DC as well as ac currents.
Since iron is absent in the working parts of the instruments, these instruments are free.
from hysteresis and eddy current errors.
Answer:
Disadvantages. (i) They have a low torque/weight ratio and hence have a low sensitivity. (ii) Low torque/weight ratio gives increased frictional losses. (iii) They are more expensive than either the PMMC or the moving iron type instruments.
Explanation:
please mark me as brainlist and thanks if useful