The Principle Work of Electrodynamometer ( Revision advice needed if some information are wrong)

[Electrokids]

Electrodynamometer

Electrodynamometer is a device that we can use for measuring volts, current, and power. But mostly this used for measuring power in the circuit. For the construction of electrodynamometer wattmeter we gonna need some important part for this stuff to work.

• Moving coil, Moving coil is the component that carrying pointer which will move because of current flows on it and controlled by spring. this will connected parallel with the voltage source and the current flows through them is directly proportional to the supply voltage.The flows of currents control with the help of resistor which connects in series with the moving coil.

• Fixed Coil , connected in series with the load It is considered as a current coil because the load current flows through it. For making the construction easy the fixed coil divide into two parts. And these two elements are parallel connected to each other.

• Control – The control system provides the controlling torque to the instruments. The gravity control and the spring control are the two types of control system. Out of two, the Electrodynamometer Wattmeter uses spring control system. The spring control system is used for the movement of the pointer.

• Scales and pointers – The instruments use a linear scale because their moving coil moves linearly. The apparatus uses the knife edge pointer for removing the parallax error which causes because of oversights.

• Damping – The damping is the effect which reduces the movement of the pointer. In this Wattmeter the damping torque produces because of the air friction. The other types of damping are not used in the system because they destroy the useful magnetic flux.

The Electrodynamometer Wattmeter has two types of coils; fixed and the moving coil. The fixed coil connects in series with the circuit whose power consumption use to be measured. The supply voltage applies to the moving coil. The resistor controls the current across the moving coil, and it is connected in series with it.

The pointer is fixed on the moving coil which is placed between the fixed coils. The current and voltage of the fixed and moving coil generate the two magnetic fields. And the interaction of these two magnetic fields deflects the pointer of the instrument. The deflection of the pointer is directly proportional to the power flows through it.

Note : The principle of this is similiar with galvanometer but the different is in this kind of measuring tools the magnetic field are generated from 2 fixed coil which placed in the right side and left side of the moving coil.

source : What is Electrodynamometer Wattmeter? - Definition, Construction, Working, Theory & Errors - Circuit Globe - https://circuitglobe.com/electrodynamometer-wattmeter.html

 

[marconi]

Some questions to check your understanding of how a dynamometer works:
1. Why does the current flow through the fixed coils?
2. Why are there two fixed coils?
3. How would you calibrate the meter for zero and scaling?
4. Does the meter read real power or apparent power?
5. Does it matter if the supply voltage changes?
6. Does the meter read instantaneous or average power?
7. Will gravity have any influence? How could you remove the effect of gravity?j
8. What are the physical effects the meter uses?

 

[Electrokids]

Some questions to check your understanding of how a dynamometer works:
1. Why does the current flow through the fixed coils?
2. Why are there two fixed coils?
3. How would you calibrate the meter for zero and scaling?
4. Does the meter read real power or apparent power?
5. Does it matter if the supply voltage changes?
6. Does the meter read instantaneous or average power?
7. Will gravity have any influence? How could you remove the effect of gravity?j
8. What are the physical effects the meter uses?

thank you . i will take this as a note for me to learn more about electrodynamometer