What is difference between LPF and UPF wattmeter?
Table of Contents
- 1 What is difference between LPF and UPF wattmeter?
- 2 What is Electrodynamometer wattmeter?
- 3 What is a low power factor wattmeter working?
- 4 What is a low power factor wattmeter working and construction detail?
- 5 When measuring power with an Electrodynamometer wattmeter in a circuit have a low power factor?
- 6 What is the limitation of Electrodynamometer type wattmeter?
What is difference between LPF and UPF wattmeter?
Answer: LPF wattmeter is used to measure power in inductive circuits. As secondary side is short circuited the entire coil will be purely resistive in nature.So the power factor will be unity. So UPF(Unit Power Factor) Wattmeter is used in SHORT CIRCUIT TEST of Transformer.
What is Electrodynamometer wattmeter?
Definition: Electrodynamometer wattmeter is an instrument whose working is related to the reaction between magnetic fields of the fixed coil and moving coil which is connected across the voltage (current is directly proportional to voltage).
What is the constructional difference between the current coil and pressure coil of Electrodynamometer type wattmeter and induction type wattmeter?
Difference Between Dynamometer Wattmeter and Induction Type Wattmeter :
| Electrodynamometer Wattmeter | Induction Type Wattmeter |
|---|---|
| The current coil is split into two parts, but a single pressure coil. | Both current and pressure coils split into two parts each, placed on each of two arms of the two magnets. |
What is low power factor?
A low p.f. means a higher load current than necessary and accompanying higher line losses. Inductive loads are the main cause of a low p.f., with induction motors the major contributors. The motor may have some reserve capacity.
What is a low power factor wattmeter working?
A low power factor (LPF) wattmeter is an instrument used to measure power in low power factor circuits. This type of wattmeters is employed for power measurement in circuits whose power factor is less than 0.5.
What is a low power factor wattmeter working and construction detail?
Definition: The instrument that measures the low value of power factor accurately is known as the Low Power Factor Wattmeter (LPFW). The low power factor meter is used for measuring the power of the highly inductive circuit. It is also used in the resistive circuit which has a power factor range from 0.5 to 1.
When measuring the power with an Electrodynamometer wattmeter in a circuit have a low power factor?
when measuring power with the electrodynamometer wattmeter in a circuit having a low power factor : the current coil should be connected on the load side. the current coil should be connected on the supply side. the pressure coil should be connected on the load side.
What are the advantages of Electrodynamometer?
1)As the instrument coils are air cared, so these instruments are free from hysteresis and eddy current errors. 2)These instruments can be used on both a.c. and d.c. and since they have a precision grade accuracy, they are very useful as transfer instruments.
When measuring power with an Electrodynamometer wattmeter in a circuit have a low power factor?
What is the limitation of Electrodynamometer type wattmeter?
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. This action makes the instruments costly.