# LPF WATTMETER PDF

So LPF(Low Power Factor) Wattmeter is used in OPEN CIRCUIT TEST of Transformer. In short circuit test the secondary winding of transformer. Low Power Factor wattmeters are specially designed to measure power at low power factor. error due to inductance of of pressure coil is large at low power a UPF wattmeter be used to measure power delivered to. LPF wattmeter is used to measure power in inductive circuits. Inductive circuits have the property of lagging power factor and hence these. Author: Paolo Hermiston I Country: Congo Language: English Genre: Education Published: 23 May 2016 Pages: 663 PDF File Size: 27.80 Mb ePub File Size: 17.26 Mb ISBN: 627-5-87321-208-4 Downloads: 60931 Price: Free Uploader: Paolo Hermiston I ### Low Power Factor Wattmeter

LPF wattmeter is used to measure power in inductive circuits. Lpf wattmeter circuits have the property of lagging power factor and hence these wattmeters are used. lpf wattmeter If the connection b is used, then the power lpf wattmeter in the pressure coil circuit is also included in the meter readings. Thus it is necessary to compensate for the pressure coil current in a low power factor wattmeter.

The pressure coil current Ip lpf wattmeter through it. The field induces in the compensating coil is because of the current Ip. The field of the compensating coil and the current coil opposes each lpf wattmeter. Thus the error occurs in the pressure coil is neutralized. Compensation For Inductance of Pressure Coil The small amount of inductances is present lpf wattmeter the pressure coil of the Wattmeter.

This inductance causes the error in the reading. The lpf wattmeter coil is used in the circuit for compensating the inductance error occurs in the Wattmeter. What is Low Power Factor Wattmeter?

## Low Power Factor Wattmeter

In this category two cases diagrams arises and these are shown below: In the first category both the ends of the pressure coil is connected to supply side i. The supply voltage is equal to the voltage across the pressure coil. Lpf wattmeter coil is used to compensate the Pressure coil current.

lpf wattmeter

Capacitor is connected across the pressure coil lpf wattmeter reduce the error due to pressure coil lpf wattmeter. Control torque is made very less for high deflection. Why a LPF Wattmeter is needed? As the name suggests the low power factor meter are the instruments that measures lower values of power factor accurately.

There is a requirement of low power factor meter because, the usage of ordinary electrodynamometer wattmeter to measure power factor of a low pf load gives inaccurate results.