# What is an electrodynamics instrument and its working principle

## What is an electrodynamics instrument

Electrodynamic instrument is an instrument that depends on its operation on the reaction between the current in one or more movable coils and the current in one or more fixed coil. Describe the working principle of electrodynamic power factor meter. [7 marks]

## Describe the working principle of electrodynamic instrument.

Electrodynanometer is used extensively in measuring power. It may be used to indicate dc and ac power for any waveform of voltage and current. Electrodynamometer employs a pair of stationary coils instead of the permanent magnet. The Electrodynamometer used as a voltmeter or an ammeter has fixed coils and the movable coil connected in series, usually to measure power dissipation wattage, two regular meters power required, one connected as a voltmeter and the other one as an ammeter. Since product of voltage and current is power. However by using electrodynamometer, a single motor can read the wattage directly. An electrodynamometer-watt meter consists of stationery coils L1 and L2 connected as an ammeter in series with the circuit being measured, while the movable coil L3 with a suitable multiplier resistor is connected as a voltmeter across the component or circuit being measured. The amount of rotation of reflection of coil L3 and its pointer, is directly proportional to the current flowing through voltage across the movable coil L3. The result is that the rotation of L3 is actually proportional to the product of voltage and current, and the meter scale may be calibrated in watts. QUESTION FIVE Describe the working principle of wattmeter [4 marks] Describe the working principle of wattmeter Answer The current coils is connected in series with the line, and the voltage coil is connected across the line, both coils are wound on a metal frame of special design provided two magnetic circuit. A light aluminium disk is suspended in the air gap of the current to flow in the disk. The reaction of the voltage coil creates a torque [motor action] on the disk, causing it to rotate. The developed torque is proportional to the field strength of the voltage coil and the eddy current.nswer
Electrodynamic instrument is an instrument that depends on its operation on the reaction between the current in one or more movable coils and the current in one or more fixed coil.

## Describe the working principle of electrodynamic power factor meter.

Describe the working principle of electrodynamic power factor meter.
Electrodynanometer is used extensively in measuring power. It may be used to indicate dc and ac power for any waveform of voltage and current. Electrodynamometer employs a pair of stationary coils instead of the permanent magnet. The Electrodynamometer used as a voltmeter or an ammeter has fixed coils and the movable coil connected in series, usually to measure power dissipation wattage, two regular meters power required, one connected as a voltmeter and the other one as an ammeter. Since product of voltage and current is power. However by using electrodynamometer, a single motor can read the wattage directly.
An electrodynamometer-watt meter consists of stationery coils L1 and L2 connected as an ammeter in series with the circuit being measured, while the movable coil L3 with a suitable multiplier resistor is connected as a voltmeter across the component or circuit being measured. The amount of rotation of reflection of coil L3 and its pointer, is directly proportional to the current flowing through voltage across the movable coil L3. The result is that the rotation of L3 is actually proportional to the product of voltage and current, and the meter scale may be calibrated in watts.

## Describe the working principle of wattmeter

The current coils is connected in series with the line, and the voltage coil is connected across the line, both coils are wound on a metal frame of special design provided two magnetic circuit. A light aluminium disk is suspended in the air gap of the current to flow in the disk. The reaction of the voltage coil creates a torque [motor action] on the disk, causing it to rotate. The developed torque is proportional to the field strength of the voltage coil and the eddy current.

### 4 thoughts on “What is an electrodynamics instrument and its working principle”

1. Pretty great post. I simply stumbled upon your weblog and wished to mention that I have really loved browsing your blog posts. In any case I will be subscribing for your rss feed and I am hoping you write again very soon!

Scroll to Top