What are basic errors that can be seen dynamometer type instruments?
Errors in Dynamometer Type Wattmeter :
- Errors Due to Mutual Inductance :
- Errors Due to Connections :
- Eddy Current Errors :
- Errors Due to Stray Magnetic Fields :
- Errors Due to Vibration of Moving System :
- Temperature Error :
- Errors Due to Voltage Coil Inductance :
- Errors Due to Voltage Coil Capacitance :
What are the constructional parts of dynamometer type wattmeter?
Construction of Dynamometer Type Wattmeter A dynamometer type wattmeter primarily consists of two coils called fixed coil and moving coil. The fixed coil is splitted into two equal parts, which are placed parallel to each other. The two fixed coils are air-cored to avoid hysteresis effects when used on AC.
What are stray magnetic field errors in wattmeter?
Stray magnetic fields Because of air cored coils, any surrounding magnetic field will easily interfere with main fields inside and cause an error. A steel cylinder is placed around the coils to shield them.
Which is not the cause of error in the wattmeter?
Wattmeter reading is not affected by temperature. Explanation: Wattmeter reading is affected by change in temperature. Resistance of the pressure coil and the spring stiffness are affected by the changes in temperature.
What is the limitation of Electrodynamometer type wattmeter?
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.
What is Electrodynamometer type wattmeter?
An electrodynamometer or simply Dynamometer wattmeter is an instrument that is universally used for the measurement of DC as well as AC electric power. It works on the principle of dynamometer i.e. a mechanical force acts between two current carrying conductors.
Which of the following would cause error in wattmeter reading?
Explanation: Due to mutual inductance between the current and pressure coil in a wattmeter, errors are introduced.
Why sensitivity of a Electrodynamometer instrument is low?
These instruments have a low torque/weight ratio and hence the low sensitivity. Low torque/weight ratio gives increased frictional losses. These errors must be minimized, if high accuracy is desired.
Which coil is fixed in Electrodynamometer type wattmeter?
Construction of Electrodynamometer The moving coil is connected across the load through a series multiplier resistance (R) and carries a current (I2) proportional to the load voltage. The fixed coil is called as Current Coil and the moving coil is called as Potential Coil.
What are the errors in dynamometer type wattmeter state a few?
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 errors in Electrodynamometer wattmeter discuss its compensation methods?
Errors in Electrodynamometer Type Wattmeter
- Errors in the pressure coil inductance.
- Errors may be due to pressure coil capacitance.
- Errors may be due to mutual inductance effects.
- Errors may be due connections.
- Error due to Eddy currents.
- Errors caused by vibration of moving system.
- Temperature error.