## Torque Equation in Electrodynamometer Instruments

Electrodynamometer Instruments are widely used as an ammeter, voltmeter and wattmeter. This instrument can measure AC as well as DC quantities. This means that the torque in electrodynamometer instruments must have a finite value and unidirectional for AC and DC quantity unlike PMMC instruments. In...

## Non-uniform Scale of Electrodynamometer Type Instrument

Unlike a PMMC instrument, the electrodynamometer type instrument has non-uniform scale. The non-uniform scale of this instrument can be explained by the equation of deflection. As we know that the deflection in electrodynamometer type ammeter and voltmeter is given as Ɵ = KI2dM/dƟ for ammeter...

## Electrodynamometer Wattmeter – Construction

Electrodynamometer Wattmeter are often used for the measurement of power consumption. The construction of such instrument similar to the construction of electrodynamometer type ammeter and voltmeter. An electrodynamometer wattmeter have two types of coils. One coil is fixed and another coil is moving. The fixed...

## Working Principle of Electrodynamometer Wattmeter

Electrodynamometer Wattmeter consists of two coils, pressure coil (PC) and current coil (CC). Pressure coil is connected across the circuit whose power is to be measured and current coil is connected in series. Thus circuit voltage is impressed across the PC and CC carries the...

## Creeping in Energy Meters

Creeping in energy meters is phenomena due to which the disc of energy meter rotates even in absence of any load current in the current coil (CC) and only pressure coil (PC) is energized. The necessary condition for creeping is that PC must be energized....

## Difference between Electrodynamometer Wattmeter and Low Power Factor Wattmeter

Electrodynamometer wattmeter and Low Power Factor (LPF) wattmeters are mostly similar in construction and operation, except for the following modifications are carried out in the electrodynamometer wattmeter to convert it into a LPF wattmeter: Pressure coil resistance is kept low to increase the torque. Compensating...

## How a Capacitor does Stores Charge?

A capacitor is a device for storing charge. It is usually made up of two plates separated by a thin insulating material known as the dielectric. One plate of the capacitor is positively charged, while the other has negative charge. The charge stored in a...

## Why CT Secondary Shall Never be Kept Open?

The most important precaution which shall be taken care while working with a CT is that its secondary should never be kept open. In this post we will discuss this aspect of CT. As we know that Current Transformers (CTs) are always used with secondary...