Can anyone help me with describing the operation of the following ?

[Slidey]

The principle of operation of a moving coil instrument

The principle of operation of an electrodynamic wattmeter

Explain the principle of operation of a kWhr meter


If anyone can direct me to information that can help me out or answer these questions they would be greatly appreciated.

 

[telectrix]

wickedpedia,

 

[Brightspark2]

Google?...

 

[pencilpusher]

Homework?

 

[Slidey]

Homework?

Yes mate. Struggling to find decent information I can read and write my own on!

 

[tazz]

Ok if we use a resistor of say 1.5 ohm but high wattage say 100amp the resistor would vertually be a piece if metal strip.....This is commonly call a shunt. if we place this shunt in series of our supply and powered circuit, we get a very slight volt drop. if we measure the voltage across this shunt we will get a reading in mv proportional to the current being drawn. So now we have an amp meter, rescaled from mv to amps. If you now know the current, and you measure the voltage you can calculate the wattage. modern methods use inductive coils but maybe this will give you an idea of now how to calculate

 

[Richard Burns]

Try the preview of this book from page 73 onward, this may help explain the principles.

 

[Knobhead]

Click HERE

 

[Knobhead]

Ok if we use a resistor of say 1.5 ohm but high wattage say 100amp the resistor would vertually be a piece if metal strip.....This is commonly call a shunt. if we place this shunt in series of our supply and powered circuit, we get a very slight volt drop. if we measure the voltage across this shunt we will get a reading in mv proportional to the current being drawn. So now we have an amp meter, rescaled from mv to amps. If you now know the current, and you measure the voltage you can calculate the wattage. modern methods use inductive coils but maybe this will give you an idea of now how to calculate

Shunt ammeters are normally only used for DC.